記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本野生動物医学会  

<p>　日本のツキノワグマ（<i>Ursus thibetanus</i>）は，ミトコンドリアDNA（mtDNA）のDループ領域における約700bpの配列に基づいたハプロタイプの解析により，分子系統が3系統（東部，西部，南部クラスター）に分かれていることが明らかとなっている。2012年，環境省は九州のツキノワグマ個体群について，1941年の記録を最後に信頼できる記録や情報が無いことから絶滅を宣言した。現在，九州のツキノワグマ個体群に関する試料および遺伝的な解析結果は非常に少ない状況であることから，九州のツキノワグマの分子系統学的な特徴は不明確である。本個体群の分子系統を明らかにすることは，アジア大陸から日本へのツキノワグマ個体群の軌跡を理解する上で重要な情報になるだろう。本研究では，九州の様々な場所で発見された4つの古い骨の試料を用いて，Dループ領域の約700bpの配列に基づいたハプロタイプを解析した。その結果，九州のツキノワグマについて2つの新しいハプロタイプを検出することに成功した。これら新しいハプロタイプは，両方とも西部クラスターに属するものであった。本研究の結果は，中国地方西部と九州の間でツキノワグマが連続的に分布していたこと，および生息地の分断後に遺伝的変異が生じたことを示唆した。また，これらの結果はアジア大陸から日本列島へのツキノワグマの移動に関する先行研究の考察を支持するものであった。</p>

DOI： 10.5686/jjzwm.28.35

DOI： 10.5686/jjzwm.28.35

CiNii Research

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）   出版者・発行元：一般社団法人 日本質量分析学会  

DOI： 10.5702/massspec.s23-05

CiNii Research

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Limnology and Oceanography: Methods  

This study aimed to assess whether benzalkonium chloride (BAC) addition to water samples could be used as a disinfectant in the radiocarbon (14C) analysis of dissolved inorganic carbon (DIC). We investigated the effectiveness of BAC addition in inhibiting 14C changes in DIC due to microbial activity during water preservation. The DIC and 14C concentration of natural waters (groundwater, seawater, river water, and lake water) without BAC increased by 1.4–3.3 mg L−1 and 1.8–4.2 percent modern carbon (pMC) for 2 weeks, and 2.2–7.9 mg L−1 and 3.0–11.9 pMC for 4 weeks, respectively, while none of the BAC-treated water samples, excluding seawater, exhibited changes in DIC or 14C concentration. Although slight increases in DIC and 14C concentrations in seawater with BAC treatment were observed, 0.4 mg L−1 and 0.4 pMC for 2 weeks, and 1.6 mg L−1 and 1.5 pMC for 4 weeks, respectively, these changes were 20–40% lower than that in seawater without BAC treatment. Furthermore, carbon contamination into the sample water due to BAC decomposition and BAC-induced microorganism decomposition was negligible in 14C analysis, albeit using BAC solution without atmospheric CO2 contamination could be a significant issue. Our results demonstrate that BAC is an effective inhibitor of biological DIC changes for 14C analysis of freshwater samples, although slightly less effective in seawater.

DOI： 10.1002/lom3.10508

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Scopus

記述言語：日本語   出版者・発行元：Lithos  

The Late Neoproterozoic basement is exposed in the Mahabad area of northwest Iran, and it is classified into three main groups. The first is metamorphic rocks that include gneiss, schist, phyllite, and slate. The second is sedimentary rocks, which comprise shale, sandstone, and dolomite and the third is igneous rocks including granite, rhyolite, felsic tuff, and ignimbrite, which are the subject of this research. Zircon U[sbnd]Pb ages for three igneous samples show that crystallization occurred at 558–552 Ma in the late Neoproterozoic (Ediacaran). The felsic magmatic rocks have SiO2 contents of 64.3 to 78.9 wt%, Al2O3 contents of 12.0 to 16.8 wt%, low TiO2 contents (0.08 to 0.69 wt%), and large variations in K2O (0.05 to 5.46 wt%) and Na2O (1.17 to 6.70 wt%). The felsic magmatic rocks are enriched in light rare earth elements (REEs) such as La and Sm, have flat heavy REE patterns, and strong negative Eu anomalies. They are mainly weakly to strongly peraluminous and calc-alkalic to alkali-calcic rocks. A wide range of initial 87Sr/86Sr(556Ma) ratios (0.7056 to 0.7203) and negative εNd(t) values (−6.0 to −2.9) do not show clear trends of mixing/contamination among mantle, slab fluids, and/or altered oceanic crust. The Mahabad magmatic rocks were produced mainly by partial melting of graywacke, psammite, and shale at high temperatures (~800 °C), based on the zircon saturation index. S-type like granites usually form in syn- to post-collisional systems, but the Mahabad felsic rocks, which have almost the same ages as the associated sedimentary rocks, were generated in an extensional regime according to geochemical discrimination diagrams. This can be explained as follows: sediments were deeply buried during the late Neoproterozoic amalgamation of microcontinents at a subduction zone along the northern boundary of Gondwana, and then erosion of the roof and/or thinning owing to extension led to upwelling of the asthenosphere and intrusion of mafic magma, which was responsible for partially melting the buried metasedimentary rocks to generate S-type like granites and felsic volcanic rocks.

DOI： 10.1016/j.lithos.2022.106658

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Scopus

記述言語：日本語   出版者・発行元：一般社団法人 日本質量分析学会  

DOI： 10.5702/massspec.s22-19

CiNii Research

記述言語：日本語  

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： doi: 10.5575/geosoc.2022.0021

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p> 本発表では、これまであまり古海洋研究に用いられてこなかった深海サンゴのトクササンゴを活用した研究の展望を紹介する。トクササンゴは、枝状のカルサイト骨格を持ち浅海から深海まで汎世界的に分布するサンゴで、南大洋インド洋区コンラッドライズから採取された深海サンゴの大部分を占めていた。これまで深層の古海洋研究に用いられてきたアラゴナイト質の単体サンゴは、寿命が100年程度でU-Th年代の誤差範囲より短いことから、サブサンプリングの際に部位を考慮する必要が無いとされている。一方でトクササンゴは寿命が数百から1000年以上と長いため、本研究では¹⁴C年代測定、微量元素濃度の定量分析、U-Th年代測定を行い、サブサンプリング方法とその時間解像度の検討を行った。</p>

DOI： 10.14862/geochemproc.69.0_157

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>名古屋港で多量に採集された炭酸塩コンクリーションは、カニ・ウニ・貝といった生物遺骸が核となっており、化石全体がコンクリーション化している。本研究では、これらの生物の死亡年代、コンクリーションの形成年代を正確に求めることを目的とした。貝殻とウニ殻のδ13Cから生物よりも古い年代を示す代謝由来と生物と同じ年代を示す海水DIC由来の割合を求め、海水DICの14C年代を求めたところ、生物の死亡年代として7,340−7,050 cal BPが得られた。コンクリーション部の14C年代は、古い有機炭素の影響を除くと7,530−7,270 cal BPとなり、生物の死亡年代とほぼ同じとなった。この年代は大上ほか(2009)が報告している河口付近が海進から海退に転じたとする年代とほぼ同じであり、名古屋港のコンクリーションは、海水準が最も高く、流れが澱んだ環境において急速に形成したと考えられる。</p>

DOI： 10.14862/geochemproc.69.0_41

CiNii Research

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>大気エアロゾル中の炭素成分(有機炭素、元素状炭素、炭酸塩炭素等)の発生源を明らかにすることは、大気汚染の対策や、地球の気候変動の解明につながる。イラン国内では、特に都市部の大気汚染が深刻になっているが、エアロゾルの炭素成分分析はほとんどされていない。半乾燥地域のイランの大気エアロゾルには、炭素粒子だけでなく土壌粒子などの砂塵性のエアロゾルも多く含まれており、炭素成分だけでなく無機元素成分も併せて把握することがこの地域のエアロゾル発生源解析において重要である。本研究では、イラクとの国境に近い、イラン・クルディスタン州の都市大気エアロゾル中の¹⁴C濃度、δ¹³C、無機元素濃度の分析から、同地域の都市大気エアロゾルの発生源について明らかにすることを目的とした。その結果、冬季はFCの寄与が他の期間に比べて大きく、3月以降になるとnon-FCの寄与が大きいことが分かった。また、春季にはイラクなど西方から飛来した土壌粒子の増加が推察された。</p>

DOI： 10.14862/geochemproc.69.0_141

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>群馬県前橋－高崎地域の基盤を構成する前橋泥流堆積物、長野県の佐久－軽井沢地域の基盤を構成する塚原泥流堆積物に含まれる巨石のSr同位体比(87Sr/86Sr)結果から、これらの泥流は、浅間火山活動初期の山体である黒斑火山の崩壊によりもたらされたことが明らかになってきている。また、泥流堆積物に混入する樹木片の14C年代から、今から約2.7万年前の最終氷期に、山体崩壊による泥流が発生したことが明らかになってきている(佐藤ほか, 2017, 2019, 2020, 2021, 2022)。本発表では、これらの結果を紹介する。</p>

DOI： 10.14862/geochemproc.69.0_200

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>イラン高原はアルプス・ヒマラヤ造山帯の一部と考えられており、北のパレオテチス縫合帯とネオテチス縫合帯の２つの大きな縫合帯の間に位置している。イランにおけるマグマ活動の大部分は、この２つの大洋の誕生から消滅と密接に関係している。ゴンドワナ北部のアラビアプレートからイラン小大陸が分裂し、新生代に再度合体するのは、典型的なウィルソンサイクルとして考えることができる。</p>

DOI： 10.14862/geochemproc.69.0_116

CiNii Research

記述言語：日本語   出版者・発行元：Communications Earth and Environment  

The hadal zone at trenches is a unique region where forearc mantle rocks are directly exposed at the ocean floor owing to tectonic erosion. Circulation of seawater in the mantle rock induces carbonate precipitation within the deep-sea forearc mantle, but the timescale and rates of the circulation are unclear. Here we investigated a peculiar occurrence of calcium carbonate (aragonite) in forearc mantle rocks recovered from ~6400 m water depth in the Izu–Ogasawara Trench. On the basis of microtextures, strontium–carbon–oxygen isotope geochemistry, and radiocarbon analysis, we found that the aragonite is sourced from seawater that accumulated for more than 42,000 years. Aragonite precipitation is triggered by episodic rupture events that expel the accumulated fluids at 10−2–10−1 m s−1 and which continue for a few decades at most. We suggest that the recycling of subducted seawater from the shallowest forearc mantle influences carbon transport from the surface to Earth’s interior.

DOI： 10.1038/s43247-021-00317-1

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Scopus

記述言語：日本語   出版者・発行元：Lithos  

Late Neoproterozoic basement of the Soursat complex to the southeast of Shahin-Dej, NW Iran, spans an area wider than 100 km2 and is cut by Paleogene monzonite and granodiorite bodies. Zircon U-Pb dating yields monzonite and granodiorite crystallization ages of 54.7 ± 3.8 Ma and 57.7 ± 2.9 Ma, respectively. The monzonite group has relatively high MgO (2.40–7.01 wt%), Cr (37.5–233 ppm) and Ni (30.6–177 ppm), and high Sr/Y (103−132) and La/Yb (68.0–102) similar to low silica-adakites (LSA). The granodiorite group has low MgO (<1 wt%), Ni (<10 ppm) and Cr (<33 ppm), and high Sr/Y (192–361) and La/Yb (37.3–156) ratios, and are consistent as high silica-adakites (HSA). The monzonite and granodiorite have 87Sr/86Sr(i) values of 0.7045 to 0.7047 and 0.7053 to 0.7058, and εNd(t) values of +1.1 to +1.8 and − 1.9 to −0.8, respectively. The differing chemical compositions and Sr-Nd isotope ratios of these two groups of coeval adakites suggest different sources. Upon consideration of the geodynamic evolution of NW-Iran during the Cenozoic, we infer a two-stage melting process. LSA melts were first produced due to partial melting of delaminated lithosphere and then modified by fractional crystallization in the lower crust. Subsequently, HSA melts were generated during partial melting of lower crustal mafic segments in the hot root zone.

DOI： 10.1016/j.lithos.2021.106438

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Scopus

記述言語：日本語   出版者・発行元：Radiocarbon  

Tsunamis are huge disasters that can significantly damage benthic organisms and the sea-bottom environment in coastal areas. It is of great ecological importance to understand how benthic ecosystems respond to such destructive forces and how individual species are affected. Investigating the effect of such disasters on animals that are seldom caught alive is particularly difficult. Bivalve mollusks are especially suitable for investigating how a tsunami affects coastal benthic species because they preserve an environmental record in their shells that can be extended back in time by crossdating the records of multiple individuals. Here we studied dead shells of Mercenaria stimpsoni, a long-lived clam, and precisely determined the time of death by using nuclear bomb-induced radiocarbon (bomb-14C) and by counting annual growth increments. First, a quasi-continuous, regional bomb-14C record was created by analyzing the shells of 6 live-caught M. stimpsoni individuals. Then 27 dead shells collected from the seafloor of Funakoshi Bay were 14C-dated and analyzed. The results showed that the huge tsunami that struck northeastern Japan on 11 March 2011 caused mass mortality of this bivalve in Funakoshi Bay. Nine of the 27 clams died during the March 2011 tsunami, probably by starvation after burial by tsunami deposits or exposure above the seafloor as a result of sediment liquefaction during the earthquake. The dating method used in this study can help us understand how long-lived marine organisms with low population density are affected by huge natural disasters such as a tsunami.

DOI： 10.1017/RDC.2021.98

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Scopus

記述言語：日本語   出版者・発行元：Radiocarbon  

We developed a simple and cost-effective method for extracting carbon from dissolved inorganic carbon (DIC) in water samples without a carrier gas. This method only slightly modifies the existing vacuum line for CO2 purification in radiocarbon research laboratories by connecting several reservoirs and traps. The procedure consists of repeated cycles of CO2 extraction from water into the headspace of the reaction container, expansion of the extracted gas into the vacuum line, and cryogenic trapping of CO2. High CO2 yield (∼98%) was obtained from a variety of water samples with a wide range of DIC concentrations (0.4-100 mmol·L-1, in the case of 1.2 mgC). The δ13C fractionation depended on the CO2 yield, while the 14C concentration was constant within the error range, regardless of the CO2 yield. The average δ13C discrepancy between the results of this method and direct analyses made using the GC-IRMS was 0.02 ± 0.06‰. The standard deviations (1σ) in fraction of modern carbon (F14C) ranged from 0.0002 to 0.0004 for waters below 0.01 of F14C, and below 0.8% of F14C values for waters above 0.1. We conclude that this method is useful for effectively extracting CO2 from DIC in water and yields accurate 14C data.

DOI： 10.1017/RDC.2021.48

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Scopus

記述言語：日本語  

DOI： 10.3390/min11070717

Web of Science

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1093/petrology/egab022

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Isolated silica concretions in calcareous sediments have unique shapes and distinct sharp boundaries and are considered to form by diagenesis of biogenic siliceous grains. However, the details and rates of syngenetic formation of these spherical concretions are still not fully clear. Here we present a model for concretion growth by diffusion, with chemical buffering involving decomposition of organic matter leading to a pH change in the pore-water and preservation of residual bitumen cores in the concretions. The model is compatible with some pervasive silica precipitation. Based on the observed elemental distributions, C, N, S, bulk carbon isotope and carbon preference index (CPI) measurements of the silica-enriched concretions, bitumen cores and surrounding calcareous rocks, the rate of diffusive concretion growth during early diagenesis is shown using a diffusion-growth diagram. This approach reveals that ellipsoidal SiO2 concretions with a diameter of a few cm formed rapidly and the precipitated silica preserved the bitumen cores. Our work provides a generalized chemical buffering model involving organic matter that can explain the rapid syngenetic growth of other types of silica accumulation in calcareous sediments.

DOI： 10.1038/s41598-021-83651-w

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人日本地球化学会  

The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdusan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. Meanwhile, trace-element analysis using the inductively coupled plasma mass spectrometry (ICP-MS) technique for the volcanic glass shards and bulk samples of the B-Tm tephra is still limited. Here we give a detailed description of major- and trace-element compositions for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan to identify the tephras. The depth profiles of the major and trace elements show the significant peaks for the K₂O and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REE compositions. The trace-element compositions of the glass shards and bulk sediments show a strong tool for distinguishing the B-Tm tephra from other Japanese tephras.

DOI： 10.2343/geochemj.2.0619

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Scopus

CiNii Research

CiNii Research

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

<p>玄能石は、長さ数cm～十数cmの双角錐型、またはそれが複数組み合わさってできるX字型や金平糖型をした、イカイト（ikaite: CaCO₃6H₂O）の方解石（CaCO₃）仮晶である。海底堆積物中では、低温（＜7℃）かつ高リン酸イオン濃度の条件下で、イカイトは双角錐型などの結晶を形成する。この条件が崩れると、イカイト結晶は安定に存在することができず、粒状方解石の集合体へと変化し、その結果、玄能石が形成する。イカイトが持つこの特徴から、玄能石は特に低温環境を示す指標として用いられ、古環境復元に活用されてきた。 玄能石は、地層中に直接胚胎されることもあれば、球状～長球状の方解石質コンクリーションに内包された状態（＝玄能石コンクリーション）で産することもある。玄能石および玄能石コンクリーションは、ともに、世界中の様々な時代の堆積岩から産出する。また、国内では、玄能石は始新世～更新世の少なくとも35の地層で確認され、玄能石コンクリーションのタイプは、そのうち少なくとも19の地層から産出する（村宮・吉田, 2020, 深田地質研究所年報, 21号, 47–58.）。このように、玄能石および玄能石コンクリーションの分布は時間的にも空間的にも広く、このことは決して特殊な地質現象ではないことを示している。しかし、その形成プロセスは、未だ不明な点が多く、特に次のような疑問が残されていた。（1）イカイトとコンクリーションの炭素源は何か。（2）なぜ、ある時点でイカイト結晶の形成から方解石質コンクリーションの形成に切り替わるのか。（3）なぜ、玄能石の周囲にコンクリーションが形成する場合としない場合があるのか。本研究では、この疑問を解決し、玄能石および玄能石コンクリーションの形成プロセスを明らかにするため、国内の複数の地層を対象に、両者の産状調査・断面観察・薄片観察・各種分析を行った。 その結果、多くの玄能石コンクリーションには合弁の二枚貝化石、スナモグリ化石、<i>Chondrites</i>様の生痕化石群集が含まれることが分かった。また、合弁の二枚貝化石を含む玄能石も発見された。二枚貝化石が含まれる玄能石および玄能石コンクリーションでは、二枚貝の殻口部がちょうど玄能石の中心部に位置し、この部分から形成が始まったことを示唆する。玄能石コンクリーションには親生元素であるリン（P）が周辺母岩の数倍以上濃集している。玄能石内部を詳しく調べると、リンはイカイトに由来する粒状方解石には含まれず、粒状方解石の間隙を埋める方解石セメント部分にリン酸カルシウムとして濃集していることが分かった。また、玄能石およびコンクリーションは、ともに負の炭素同位体比（δ¹³C）で特徴づけられる。 この一連の証拠は、玄能石の先駆物であるイカイト結晶とそれを覆うコンクリーションの両方が、生物遺骸起源の炭素がソースとなり形成されたことを示している。これに加えて、玄能石の微細な構造と、元素分布の特徴から、玄能石コンクリーションは次のようなプロセスで形成したと考えられる。1）堆積物中に埋没した生物遺骸が分解し、周辺堆積物中に重炭酸イオンとリン酸イオンを供給する。この時、分解に伴う腐食酸の生成によって間隙水pHが低下し、リン酸イオンは間隙水に溶解する。2）この高リン酸イオン濃度環境下で、生物遺骸起源の重炭酸イオンからイカイトが形成する。3）分解の進行に伴って腐植酸の生成量が低下し、間隙水pHが上昇すると、リン酸イオンがリン酸カルシウムとして沈殿して間隙水から取り除かれる。これ以降は、生物遺骸起源の重炭酸イオンは方解石としてイカイトの周辺に沈殿して、コンクリーションが急速に形成される。4）その後の埋没・続成過程でイカイトは粒状方解石に変化し、玄能石となる。この玄能石コンクリーションの形成プロセスは、コンクリーションを伴わない玄能石および、玄能石を伴わないコンクリーションの形成も矛盾なく説明できる。つまり、２）の段階までにすべての炭素がイカイトの形成に消費されると、コンクリーションは形成せず、イカイトのみが形成する。こうしてコンクリーションを伴わない玄能石が形成する。一方、間隙水のpHが十分に低下せず、高リン酸イオン環境が整わなかった場合、あるいは間隙水温度がイカイトの沈殿には高すぎた場合、すべての炭素は方解石として沈殿し、結果として玄能石を伴わないコンクリーションが形成される。本研究で明らかになったこの一連の形成過程は、玄能石コンクリーションの産状が、初期続成過程における間隙水pHの指標になりうることを示している。（引用文献：村宮・吉田, 2020, 日本の玄能石と玄能石コンクリーション：産出地層の堆積環境．深田地質研究所年報, 21号, 47–58.）</p>

DOI： 10.14863/geosocabst.2021.0_003

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

<p>炭酸カルシウム（CaCO₃）を主成分とする炭酸塩コンクリーションは海成堆積岩に普遍的に産出する．炭酸塩の炭素同位体組成（δ¹³C），コンクリーション周辺の堆積構造，コンクリーション成長モデルなどから，これらの炭酸カルシウムは，内包される生物の軟体組織部分を起源とする炭酸（HCO₃^–）と堆積物中の間隙水に含まれる海水中のカルシウムイオン（Ca²⁺）が反応し，堆積後数ヶ月〜数年の短期間に急速に形成されたことが明らかになっている^1,2．この炭酸カルシウムは，海底下の地層中で成長する際，Caと化学的挙動が類似したストロンチウム（Sr）も海水中から取り込む．一般に，海成炭酸塩（岩）に含まれるSrの同位体比（⁸⁷Sr/⁸⁶Sr）は，過去の海水のSr同位体比の変動曲線³との対比に基づき，堆積年代を推定することに利用されている（Sr同位体層序年代）．コンクリーション中の炭酸塩に含まれるSrは，続成作用や変質作用の影響が小さければ，堆積当時の海水中のSr同位体比を保持することとなり，年代指標に成り得ると考えられる．本研究では，石灰岩層などの堆積年代の決定に用いられているSr同位体層序を，炭酸塩コンクリーションに適用し，その有効性について検討した．</p><p>　試料は，富山県八尾地域と宮崎県の宮崎平野〜鵜戸山地に広がる宮崎層群に産出するコンクリーションである．八尾地域の中新統黒瀬谷層に産出するツノガイ（<i>Fissidentalium </i>spp.）化石を含むコンクリーション（6試料）と化石を含まないコンクリーション（5試料），ツノガイの貝殻部分（4試料），新第三紀中新世（約1100万年前）〜第四紀更新世（約150万年前）の海成層（宮崎層群）に産出するコンクリーション（13試料）を分析に供した．コンクリーション中のカルサイトを希酢酸で溶出させ，カルサイトフラクションから陽イオン交換樹脂カラムでSrを単離した．Sr同位体比は名古屋大学の表面電離磁場型質量分析計VG Sector 54-30で測定した．</p><p>　分析の結果，八尾地域のツノガイ化石を含むコンクリーションのカルサイト部分の ⁸⁷Sr/⁸⁶Srは0.70865–0.70867とほぼ一定であり，ツノガイの貝殻部分の⁸⁷Sr/⁸⁶Sr = 0.70865–0.70868とも一致した．また，化石を含まないコンクリーションのカルサイト部分の ⁸⁷Sr/⁸⁶Srは0.70865–0.70868であり，これらもツノガイの貝殻部分の値と一致した．Sr同位体層序年代を求めたところ，ツノガイの貝殻部分の年代は16.86±0.34 Maであり，ツノガイ化石を含むものと含まないものの両グループの ⁸⁷Sr/⁸⁶Srの平均値から求めた年代は17.02±0.27 Maであった⁴．このコンクリーションのSr同位体層序年代は，珪藻化石層序・古地磁気層序（15〜17 Ma）⁵や凝灰岩層のジルコンのU–Pb，FT年代（16.4±1.2 Ma〜17.6±0.3 Ma）⁶などから得られている堆積年代とも一致している．これは，炭酸塩コンクリーションが地層の堆積直後に形成されたことを示しており，堆積直後に急速にコンクリーションが形成されたというこれまでの研究結果とも矛盾しない．</p><p>　一方，宮崎層群のコンクリーションのSr同位体層序年代は，化石層序などから得られている堆積年代と大きく異なる年代値となった．すなわち，宮崎層群の炭酸塩コンクリーション中のSrは堆積当時の海水のSr同位体比を反映していない．また，八尾地域のコンクリーションのδ¹³C_VPDB値は–19.2〜–15.9‰と低く，生物の軟体組織部分を起源とする炭素成分を示唆しているが¹，宮崎層群のコンクリーションのδ¹³C_VPDB値は–6.5〜+1.1‰と高く，海水の無機炭酸を起源とする炭素成分を示唆している．ストロンチウムと炭素の同位体組成の結果は，宮崎層群のコンクリーションのカルサイト部分の起源物質が八尾地域のコンクリーションとは異なっていることを示しており，コンクリーション形成時の間隙水の性質の違い，形成後の変質の程度の違いなどを反映している可能性がある．</p><p>　本講演では，炭酸塩コンクリーションの産状，微量元素組成のデータも併せて，Sr同位体による年代決定が可能な炭酸コンクリーションの選別についてさらに議論する．</p><p>¹ Yoshida <i>et al.</i>, <i>Sci.Rep. </i>5, 14123 (2015); ² Yoshida <i>et al.</i>, <i>Sci.Rep. </i>8, 6308 (2018); ³ McArthur <i>et al., </i>In: The Geologic Time Scale 1, 127-144 (2012); ⁴ Yoshida <i>et al.</i>, <i>Sci.Rep. </i>9, 1003 (2019); ⁵ 柳沢, <i>地調月報</i> 50, 139-165 (1999); ⁶ 中嶋ほか, <i>地質雑</i> 125, 483-516 (2019)</p>

DOI： 10.14863/geosocabst.2021.0_007

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

<p>球状コンクリーションには、カルシウム、鉄、シリカを主成分とするものがあり、多くは球状をなす[1~4]。鉄コンクリーションについては、火星のコンクリーション（ブルーベリー）のアナログとして[3]、またシリカコンクリーションについては、石油の熟成過程で形成されることなどが明らかとなっている[4]。とくにカルシウムを主成分とするコンクリーションについては、数億年〜完新世の海性堆積岩中から発見され、保存良好な生物遺骸（化石など）を内包するなど1900年代初頭から知られていたものの、詳細な成因については不明のままであった。その成因や形成速度について国内外の数百に及ぶ試料を調査・分析し、それらの共通性質として、コンクリーション内部のCa濃度がほぼ一定でδ¹³Cが低く有機物炭素由来であること、元素プロファイルからCaCO₃の濃集・沈殿が、コンクリーションの縁（反応縁;Reaction Front）で生じつつ、炭素起源の生物を取り巻くように内部から外へと急速に成長すること、を明らかにした[1,2]。このプロセスは、コンクリーションの縁（反応縁）の幅（L cm）と、堆積物中の炭素（重炭酸イオン）の 拡散係数（D cm²/s）及び反応速度（V cm/s）が 'D = LV' という単純化した関係式で示され、「拡散成長速度ダイアグラム」として表すことができる。このダイアグラムから、全てのコンクリーションの形成速度を見積もることが可能であり[2,5,6]、直径1メートルサイズでも形成速度は数年程度と見積もられる。これは、コンクリーションが未固結海底堆積物中で形成されたとする堆積学的証拠と矛盾しない[2,6]。またコンクリーションは非常に緻密で、露出した後も風化に強く、内部化石の保存状態も良好である。これは、炭酸カルシウムが堆積物中の空隙をシーリングし、後世的な風化プロセスの進行を抑制するためである[5]。このプロセスを工学的に応用できれば、非常に短期間で長期的なシーリングが実施可能となる。</p><p></p><p><u><b>コンクリーションのシーリング状態・工学的評価</b></u></p><p>球状コンクリーションは、周辺地層の約10〜20倍の50〜60wt%のCaCO₃を含む。この割合は，海底堆積物 の初期空隙率に近い値を示し、コンクリーションが未固結堆積物中で形成されたことと整合的である。コンクリーションの空隙率は、その多くが5%以下と非常に緻密で、透水係数も10^-12m/sオーダーと花崗岩に匹敵するものも認められる。このような緻密なシーリング状態が、コンクリーション中の化石の長期保存を可能にすると考えられる[2,5,7]。 </p><p></p><p><u><b>コンクリーション化剤の開発</b></u></p><p>コンクリーション化プロセスの応用として、地下岩盤中での水みちなどの空隙をシーリングさせるための‘コンクリーション化剤(コンクリーションシード(略称コンシード))’を積水化学工業と共同で開発してきた（特許第6889508号）。このコンクリーション化剤の利点は、１）従来の物理的圧入法と異なり、元素の拡散・沈殿によりミクロンオーダー以下の微細な空隙もシーリングが可能。２）元素の拡散によるシーリングであることから、地下水の(高)間隙水圧の影響を受けない。３）地下水中の自然由来の重炭酸イオンやカルシウムイオンも活用可能であり、持続的かつ長期的なシーリングが可能、という点である。</p><p></p><p><b><u>応用化のための原位置実証試験</u></b></p><p>開発したコンクリーション化剤を用いた実証試験を、北海道幌延深地層研究センターにおいて実施中である。最新の結果として、地下坑道周辺の掘削に伴う緩み領域(EDZ)岩盤の透水性が、コンクリーション化剤の注入により数ヶ月で約2オーダー低下し、周辺母岩とほぼ同様の透水性にまで改善されつつあることが示されている。今後、コンクリーション化剤の注入孔をオーバーコアリングし、コンクリーション化の進行度合いを各種実験/分析によって検証する。将来的には、岩盤中の割れ目帯や断層破砕帯などの大規模水みちのほか、既存トンネルの修復、さらにはCCSや石油廃孔の長期シーリングなどへも応用する計画である。</p><p></p><p>文献[1] Yoshida et al. (2015) Scientific Reports, [2] Yoshida et al. (2018) Scientific Reports, [3] Yoshida et al. (2018) Science Advances, [4] Yoshida et al. (2021) Scientific reports, [5] Muramiya et al. (2020) Sedimentary Geology, [6] Yoshida et al. (2019) Scientific Reports, [7] Yoshida et al. (2020) Geochemical Journal.</p>

DOI： 10.14863/geosocabst.2021.0_009

CiNii Research

記述言語：日本語   出版者・発行元：Journal of Asian Earth Sciences  

Intrusive bodies with a wide-ranging geology are distributed in the central part of the Sanandaj-Sirjan zone (C–SaSZ) in southern Ghorveh, western Iran. The zircon U–Pb ages were dated at 154–146 Ma, and were characterized by low 87Sr/87Sr(i) ratios and high 143Nd/144Nd(i) ratios that ranged from 0.7035 to 0.7061 and 0.51245 to 0.51271, respectively (positive εNd(t) values). Magma differentiation and mixing formed different magmatic rocks that range widely from gabbro to granite in the Meiham–Shirvaneh area in southern Ghorveh. However, there was no clear evidence to support the slab role for the enrichment of large-ion lithophile elements (LILEs) and light rare–earth elements (LREEs) in this area. Meanwhile, there is a possibility that some ocean island basalt-like melt, which has been reported in the Ghorveh area for the same period, was involved in the minor enrichment of LILEs and LREEs. The high development of the released depleted mantle melts, with a minor role played by crustal components, accelerated the thinning of the continental crust in an extensional regime such as continental rift in the C–SaSZ during the Jurassic. This rift was responsible for the sequential injection of mafic magma with a wide range of magma mixing and mingling in southern Ghorveh during the Late Jurassic. As a result, we observed a wide range of intrusive rocks from gabbro to granite with different compositions, which included some clear mixing and hybrid textures. This finding demonstrated how the released mantle melt formed a thicker crust in western Iran.

DOI： 10.1016/j.jseaes.2020.104469

Web of Science

Scopus

記述言語：日本語   出版者・発行元：Mineralogy and Petrology  

Three types of amphibolites were found around a large serpentinite body in the basement of the Ohmachi Seamount in the Izu-Bonin-Mariana arc: epidote-albite amphibolite, epidote-garnet amphibolite, and garnet-zoisite amphibolite. The epidote-albite amphibolite shows a mid-ocean ridge basalt geochemical affinity based on whole-rock chemistry and Nd and Sr isotopes. The epidote-garnet amphibolite originated in an arc tectonic setting and contains relict glaucophane, showing blueschist-facies metamorphism (MD1) prior to amphibolite-facies recrystallization (MD2) that formed barroisite and paragonite. The Rb–Sr garnet-whole-rock isochron (289 ± 58 Ma) could represent the timing of blueschist-facies metamorphism. In contrast, the Rb-Sr barroisite-paragonite isochron of 67 ± 13 Ma is an errorchron or mixed age due to insufficient equilibrium with the whole-rock Sr isotope composition, with no geologic significance. The garnet-zoisite amphibolite formed in a mid-oceanic ridge setting and preserves relicts of eclogite-facies paragenesis (MR2a), including zoisite, kyanite, omphacite, and magnesiohornblende, followed by amphibolite-facies metamorphism (MR2b) represented by actinolite and then by a later MR3 event that resulted in the formation of edenite and pargasite. The Rb–Sr mineral isochron (244 ± 28 Ma) defined by zoisite + magnesiohornblende/actinolite + edenite/pargasite represents the time at which the rock recrystallized in the amphibolite facies (MR2b) or cooled (MR3) through ~ 500 °C (the closure temperature of amphibole), indicating that eclogite-facies metamorphism occurred before ca. 244 Ma. The two Permo-Triassic isochron ages (289–244 Ma) indicate that the high-pressure metamorphism of the basement in the Ohmachi Seamount occurred by ancient subduction rather than along the modern subduction zone. The different protoliths and P–T conditions of amphibolites exposed in the serpentine mélange of the Ohmachi Seamount represent a mixture of rocks exhumed to the Earth’s surface from various depths in the subducted complex, which are interpreted as evidence for a fossil subduction channel preserved in a modern intra-oceanic arc.

DOI： 10.1007/s00710-020-00705-z

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sedimentary Geology  

Spherical carbonate concretions are present in sedimentary strata of varying geological ages worldwide. Recent studies reveal that calcium carbonate concretions form very rapidly around dead organisms after burial in the seabed. However, the formation mechanism of spherical dolomite concretions in marine sediments, particularly the carbon source and the reason for their spherical shape, are still moderately known. This study aims to elucidate their formation process and diagenetic evolution through the characterization of the structure, mineralogical composition, and geochemistry in and around a concretion. Here, detailed studies were conducted on a gigantic dolomite concretion approximately 170 cm in diameter, which formed in tuffaceous fine sandstone of the Morozaki Group in Chita Peninsula, Japan. The Ca and Mg distributions in and around the concretion show that it rapidly formed by outward diffusion of bicarbonate from the carbon source in its center. The δ13C values ranging from +4.4‰ to +7.5‰ and large volume of dolomite cement indicate that the dolomite concretion formed at shallow depth from methanogenic organic matter decomposition during rapid sedimentation. Heulandite occurred only in the surrounding rock matrix comprising altered volcanic glasses because of high temperature during deep burial up to 2–4 km depth. This gigantic dolomite concretion properly preserves its evolution and changes in the superimposed post-depositional environment. This study shows that gaining a better understanding of spherical dolomite concretions can potentially help reveal the burial process of sediments during early diagenesis.

DOI： 10.1016/j.sedgeo.2020.105664

Web of Science

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人日本地球化学会  

<p>Various granitoid bodies from the Neoproterozoic to Late Cenozoic intruded in the Sanandaj-Sirjan zone (SaSZ) in western Iran. In this research, we have compiled data for rare earth elements (REEs) concentration in the granitoid bodies which we have collected in the northern part of the SaSZ in this decade. The abundances of ∑REEs in a part of the granitoids are over 500 and even 2000 ppm. Although most of the granitoids such as Ebrahim Atar, Panjeh, Ghorveh, Kangareh, and Ghalaylan have low or normal values of ∑REEs and are not hopeful for future exploration, some hopeful bodies such as the Mobarak Abad granitoid in the east of Sanandaj and the Hassansalaran A-type granites in the east of Saqqez are recognized as REEs potential for future exploration. The chemical compositions of the REEs-enriched granites such as the Hassansalaran A-type and Mobarak Abad granites infer that the granites were generated in an extensional tectonic regime. Our finding shows that the granitic rocks which are related to the within plate tectonic setting in the SaSZ, NW Iran, can be considered as good potential for REEs exploration in the future.</p>

DOI： 10.2343/geochemj.2.0584

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記述言語：日本語   出版者・発行元：Dentistry Journal  

Streptococcus mutans, a bacterium that causes dental plaques, forms a biofilm on tooth surfaces. This biofilm can cause gingivitis by stimulating the gingival margin. However, there is no established treatment for biofilm removal. Hainosan (Painongsan), a traditional Japanese Kampo formula, has been used to treat gingivitis. Therefore, we investigated the biofilm suppressive effects of the hainosan extract (HNS) and its components on S. mutans. We conducted scanning electron microscopy and confocal laser microscopy analyses to clarify the anti-biofilm activities of HNS and its crude drugs. We also performed a quantitative RT-PCR assay to assess the biofilm-related gene expression. HNS showed a significant dose-dependent suppressive effect on biofilm formation. Both the scanning electron microscopy and confocal laser microscopy analyses also revealed the significant inhibitory effects of the extract on biofilm formation. Transmission electron microscopy analysis showed that HNS disrupted the surface of the bacterial wall. Furthermore, HNS reduced the hydrophobicity of the bacteria, and suppressed the mRNA expression of β-glucosyltransferase (gtfB), glucosyltransferase-SI (gtfC), and fructosyltransferase (ftf). Among the constituents of hainosan, the extract of the root of Platycodon grandiflorum (PG) showed the strongest biofilm suppression effect. Platycodin D, one of the constituent natural compounds of PG, inhibited S. mutans-associated biofilm. These findings indicate that hainosan eliminates dental plaques by suppressing biofilm formation by S. mutans.

DOI： 10.3390/DJ8030071

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Radiocarbon  

We studied a suitable procedure for preparing of water samples used in radiocarbon intercomparisons involving dissolved inorganic carbon (DIC). The water samples must have inter-batch consistency and stable 14C concentrations and no sterilizing agent (e.g., HgCl2) should be added, in order to avoid the production of hazardous material. Six water samples, containing widely different amounts and types of salts, DIC, and 14C concentrations (1-100 pMC), were prepared in order to assess the procedure. Sample consistency was investigated through δ13C and chemical compositions; their low variabilities indicate that our procedure can be applied to radiocarbon intercomparison. A specific sample preparation protocol was developed for this kind of applications.

DOI： 10.1017/RDC.2019.104

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Radiocarbon  

In our research on traditional clothing and accessories in the Ryukyu Islands of Japan, we have collected cloth fragments from traditional Ryukyuan costumes and other fabric products for radiocarbon (14C) dating. In this study, the cloth samples from historical costumes of noro priestesses (two samples), men and women from high-status families (five samples), and non-costume cloth products (seven samples), belonging to the traditional hereditary religious system of the ancient Ryukyu Kingdom, which lasted from approximately the 14th century AD to 1829 were analyzed. One extra sample originated from a silk shawl known as a Manila shawl. The oldest among the 15 samples dates back to the mid-15th century, but some newer ones belong to the unclear calibrated age range of AD 1650-1950. The measured dates are very consistent with the historical record, suggesting that acetone and acid-alkali-acid treatments are an adequate cleaning method for radiocarbon dating of silk and cotton samples produced in the late Middle Age and later.

DOI： 10.1017/RDC.2019.105

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Radiocarbon  

This study characterized cremated bone to better understand isotope exchanges during burial, using archeological samples. The cremated bones of Jokei, a Buddhist monk (AD 1155-1213), found in an urn from the Jisho-in Temple, Nara Prefecture, Japan, were used for the analysis. 14C dates were determined for eight of Jokei bone fragments of different colors (black, gray, and white). The white fragments had the highest X-ray diffractometry (XRD) crystallinity index (CI) values (0.89-1.05), Fourier-transform infrared spectroscopy (FTIR) splitting factor values (IRSF) of 5.3-7.1, and the lowest Ba concentrations. The calibrated date of the white bone fragments is 1152-1216 cal AD, consistent with Jokei's lifespan, showing these fragments yield reliable 14C ages. Meanwhile, the black and gray fragments, which probably experienced lower temperatures during cremation, had lower CI and IRSF values of 0.25-0.46 and 4.2-4.9, respectively, and higher Ba concentrations. The black and gray fragments tended to show unreliable younger 14C dates and higher 87Sr/86Sr values close to the soil value due to soil contamination. The results in this study indicate that it is important to check crystallinity of apatite and soil contamination using chemical indexing methods such as Ba capture, to clarify the reliability of 14C dates for cremated bone samples.

DOI： 10.1017/RDC.2019.97

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記述言語：日本語  

DOI： 10.1016/j.actaastro.2019.09.025

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記述言語：日本語   出版者・発行元：Journal of Ethnopharmacology  

Ethnopharmacological relevance: In traditional Chinese medicine (TCM), honey has been used as an additive in the heat-processing of herbal medicines to enhance their immunostimulatory activities. Aim of the study: We investigated the immunostimulatory activity of heated honey in vitro and in vivo. Materials and methods: For the in vitro study, we compared the differences among the inducible effects of honey subjected to various heating conditions on granulocyte colony-stimulating factor (G-CSF) secretion from the cultured enterocytes and investigated the active ingredient. For the in vivo study, we conducted a survival test of mice infected by Streptococcus pyogenes with and without oral administration of heated honey. Results: We found that heating the honey induced the appearance of G-CSF secretions from the cultured enterocytes, and that this appearance depended on the heating temperature and time. No G-CSF secretions appeared when honey was not heated. Mice infected with Streptococcus pyogenes that were fed heated honey revealed prolonged survival. The active ingredient in heated honey was a high-molecular compound with about 730 kDa. When this compound was hydrolyzed, galactose, glucose, rhamnose, α-ribofuranose β-ribofuranose 1,5′:1′,5-dianhydride, and 5-hydroxymethylfurfural were generated. Conclusions: Heated honey reveals immunostimulatory activity both in vitro and in vivo. These results support the scientific evidences of the TCM theory.

DOI： 10.1016/j.jep.2018.09.019

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記述言語：日本語   出版者・発行元：BioScience Trends  

Streptococcus pyogenes causes several infectious diseases such as tonsillitis, cellulitis, and streptococcal toxic shock syndrome. As antibiotics are used for the general treatment of S. pyogenes infection, cases of treatment failure due to drug-resistant bacteria have increased. Lonicera caerulea var. emphyllocalyx (LCE) has been used as a folk medicine in northern Japan (Hokkaido). In this study, we investigated the antibacterial effect of methanol extracts of the fruit, stem, and leaf of LCE (LCEEs) against S. pyogenes using disk diffusion assay. As LCEE (fruit) had the strongest antibacterial activity among the three LCEEs, we focused on functional analysis of antibacterial effects of LCEE (fruit). LCEE (fruit) suppressed the growth of S. pyogenes in a dose-dependent manner. Morphological analysis by transmission electron microscopy demonstrated that LCEE (fruit) damaged the shape of S. pyogenes. Microplate and confocal laser microscopy analysis showed that biofilm formation was also suppressed by LCEE (fruit) in a dose-dependent manner. To further evaluate the surface structure of these biofilms, we performed hydrophobic analysis, which demonstrated that LCEE (fruit) reduced the hydrophobicity of the bacterial surface structure. Our data demonstrated that LCEE (fruit) had anti-bacterial and anti-biofilm effects on S. pyogenes in vitro, suggesting that the direct anti-bacterial effects of the LCEE (fruit) may be useful for treatment of local S. pyogenes infection.

DOI： 10.5582/bst.2019.01005

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記述言語：日本語   出版者・発行元：BioMed Research International  

Porphyromonas gingivalis is an important pathogenic anaerobic bacterium that causes aspiration pneumonia. This bacterium frequently forms biofilms in the oral cavity and in respiratory tract-associated medical devices. Bacterial colonization that occurs in association with this biofilm formation is the main reason for incurable aspiration pneumonia. The Lonicera caerulea var. emphyllocalyx (LCE) fruit has been used in folk medicine in Hokkaido, the northern part of Japan. The aim of this study was to elucidate one of the antimicrobial mechanisms of LCE methanol extract (LCEE) - the inhibitory effect of LCEE on biofilm formation by P. gingivalis. Our results show that LCEE significantly reduced biofilm formation by three different P. gingivalis isolates in a concentration- and time-dependent manner that were quantified by the adsorption of safranin red. When LCEE was added to biofilms already formed by P. gingivalis, LCEE did not degrade the biofilm. However, treatment with LCEE significantly promoted the removal of existing biofilm by vibration compared to that of control. We also confirmed biofilm formation in LCEE-treated P. gingivalis in tracheal tubes using scanning electron microscopic (SEM) analysis. Cyanidin 3-O-glucoside (C3G), one of the components of LCE, also inhibited the formation of biofilm by P. gingivalis in a concentration-dependent manner. Our results reveal that LCEE may be an effective antibacterial substance for P. gingivalis-induced aspiration pneumonia because of its role in the suppression of bacterial biofilm formation in the oral cavity.

DOI： 10.1155/2019/3547858

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記述言語：日本語   出版者・発行元：BioMed Research International  

Streptococcus pyogenes (S. pyogenes) causes several infectious diseases such as tonsillitis, cellulitis, and streptococcal toxic shock syndrome. The general treatment of S. pyogenes infection is by using β-lactam antibiotics; however, the cases of treatment failure were increasing as serious problems. Lonicera caerulea var. emphyllocalyx (LCE) has been used in the folk medicine in the northern part of Japan, the northern part of China, Korea, and Russia. In this study, we investigated the efficacy of three parts (fruit, stem, and leaf) of Lonicera caerulea var. emphyllocalyx extract (LCEEs) against murine S. pyogenes infection. Oral administration of LCEEs increased the mortality in murine model, and the extracts of its stems and leaves were more effective than the fruit extract significantly. Murine splenocytes and mesenteric lymph nodal cells treated with LCEEs suppressed the excess production of inflammatory cytokine such as TNF-α in comparison to those from untreated cells. LCEEs stimulated the differentiation of pluripotent hematopoietic stem cells in those murine lymph nodal cells. It also activated the proliferative response of murine lymph nodal cells. We also found that the stem and leaf extracts seemed to be more effective than the fruit extract in those phenomena. The concentration of lignins in LCEE prepared from the stems was larger than that from leaves, and that was larger than that from the fruits. Our data suggest that LCE, especially the stems and the leaves, may be useful for the treatment of S. pyogenes infection.

DOI： 10.1155/2019/1797930

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Science Advances  

Spherical Fe-oxide concretions on Earth, especially in Utah, USA, have been investigated as an analog of hematite spherules found in Meridiani Planum on Mars to support interpretations of water-rock interactions in early Mars. Although several formation mechanisms have been proposed for the Fe-oxide concretions on Earth, it is still unclear whether these mechanisms are viable because a precise formation process and precursor of the concretions are missing. This paper presents evidence that Fe-oxide concretions in Utah and newly found Fe-oxide concretions in Mongolia had spherical calcite concretions as precursors. Different formation stages of calcite and Fe-oxide concretions observed, both in Utah and Mongolia, indicate that calcite concretions initially formed within eolian sandstone strata and were dissolved by infiltrating Fe-rich acidic waters to form spherical FeO(OH) crusts due to pH buffering. The similarity between these Fe-oxide concretions on Earth and the hematite spherule occurrences in Meridiani Planum, combined with evidence of acid sulfate water influences on Mars, suggest that the hematite spherules also formed from dissolution of preexisting carbonate spherules possibly formed under a dense carbon dioxide early martian atmosphere.

DOI： 10.1126/sciadv.aau0872

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Geology  

The strontium isotope value (87Sr/86Sr) is often used to identify the origins of agricultural products and the movements of ancient people. Maps delineating the distribution of 87Sr/86Sr values can therefore be of great use. Previous 87Sr/86Sr distribution maps of stream sediments covering small areas of Japan largely reflect the 87Sr/86Sr values of underlying bedrock. It remains unclear, however, whether the 87Sr/86Sr values of stream sediments may also reflect the 87Sr/86Sr values of the nearby vegetation and fauna. We sought to resolve this question by investigating the relationship between 87Sr/86Sr values in biological samples and in geological samples from the sites from which the biological samples grew. The geological samples consisted of soil samples from 2 paddy fields and 13 bed sediment samples (grain size <180 μm) from streams surrounding the paddy fields. All were collected from regions underlain by Inagawa granite bedrock, i.e., granite geology, around Toyota, Aichi Prefecture, Japan. The biological samples consisted of 4 rice plants and 1 wild boar bone, all collected in or near the same paddy fields. In the geological samples, the 87Sr/86Sr values of water-extracted Sr (water-soluble Sr) and ammonium-acetate-extracted Sr (exchangeable Sr) fractions in paddy soils were almost the same as each other (0.7098–0.7100) and slightly lower than the 87Sr/86Sr values of bulk Sr fractions (0.7099–0.7106). The 87Sr/86Sr values of biological samples (0.7098–0.7100) were also similar to those of the water-soluble Sr and exchangeable Sr fractions in paddy soils, though they varied among the parts of plants analyzed. This indicates that exchangeable Sr is absorbed by plants from soils through nutrients and water, and ingested by herbivorous animals from soils through plants and water. The 87Sr/86Sr values of bulk Sr in paddy soils ranged somewhat widely, while those from stream sediments collected around paddy fields were less variable (0.7099–0.7100). The difference in 87Sr/86Sr values between the paddy soils and stream sediments, samples similarly derived from Inagawa granite bedrock, may be related to the variable degree of weathering, and ultimately to the mineral composition, of the samples. This difference, however, was smaller than the range of 87Sr/86Sr values observed in the watershed geology. We therefore propose that in a silicate-dominated geology of the type typical of Japan, an 87Sr/86Sr spatial distribution map (using both exchangeable Sr and bulk Sr fractions in stream sediments) can provide useful guidance for identifying the geographic origins of food or for serving other related purposes.

DOI： 10.1016/j.chemgeo.2018.03.013

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記述言語：日本語   出版者・発行元：Evidence-based Complementary and Alternative Medicine  

Streptococcus pyogenes (S. pyogenes) is a species of Gram-positive coccoid bacteria having many virulence factors. Its capsule and exotoxins can cause upper respiratory tract infections such as sinusitis. The general treatment for S. pyogenes-induced sinusitis is administration of antibiotics such as penicillin and macrolides; however, a serious problem associated with these antibiotics is their attenuated effect. Shin'iseihaito (Xinyiqingfeitang), a formula of Japanese traditional Kampo medicine and traditional Chinese medicine, has been used for the treatment of sinusitis. In general, formulas of Japanese traditional Kampo medicine are orally administered. This is in contrast to certain formulas of traditional Chinese medicine, which are being recently administered intramuscularly or intravenously. Regarding these traditional Chinese medicine formulas, the injection methodology is reported to be more effective than oral intake. In this study, we compared the efficacy between orally and intramuscularly administered Shin'iseihaito against S. pyogenes-induced sinusitis. We evaluated the antibacterial effect of Shin'iseihaito extract (SSHT) against S. pyogenes by K-B disk diffusion assay. Furthermore, we investigated the nasal colonization of S. pyogenes, determined cytokine (TNF-α, IL-1β, and IL-6) levels, and conducted a splenocyte proliferative assay in a murine sinusitis model. SSHT displayed direct anti-S. pyogenes activity. Intramuscular administration of SSHT decreased the nasal colonization of S. pyogenes compared with oral administration. Thymidine uptake analysis revealed that the proliferation of splenocytes from S. pyogenes-infected mice under intramuscular SSHT treatment was upregulated compared to that of splenocytes from S. pyogenes-infected mice under oral SSHT treatment. We also found that TNF-α, IL-1β, and IL-6 levels in the nasal discharge from intramuscularly treated S. pyogenes-infected mice were lower than those from orally treated mice. Our findings suggest that intramuscular administration of Shin'iseihaito may be useful for the treatment of murine S. pyogenes-induced sinusitis.

DOI： 10.1155/2018/8901215

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記述言語：日本語   出版者・発行元：Evidence-based Complementary and Alternative Medicine  

Streptococcus pneumoniae (S. pneumoniae) causes sinusitis. The general treatment of S. pneumonia sinusitis is by using antibiotics; however, one of their serious problems is the attenuation of their effect. Shin'iseihaito (Xinyiqingfeitang), a formula of Japanese traditional Kampo medicine, has been used for the treatment of sinusitis in Japan. In this study, we investigated the efficacy of Shin'iseihaito against S. pneumoniae-caused sinusitis in mice. Oral administration of Shin'iseihaito extract (SSHT) decreased the nasal colonization of S. pneumoniae in both prophylactic and therapeutic treatments, respectively, and the former was more effective than the latter. Histopathological analysis revealed that the epithelial tissue from S. pneumoniae-infected nose under SSHT treatment recovered the tissue destruction in comparison to infected nose. We also confirmed this result by scanning electron microscopic analysis. Murine peritoneal macrophages from SSHT-treated mice had significant phagocytic activity in comparison to those from untreated group. We also found that tumor necrosis factor-α, interleukin-1β, interleukin-6, and monocyte chemotactic protein-1 levels and the migration of macrophages from S. pneumoniae-infected mice with the treatment with SSHT were increased compared to those from untreated group. Our data suggest that Shin'iseihaito may be useful for the treatment of S. pneumoniae-induced sinusitis.

DOI： 10.1155/2017/4293291

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記述言語：日本語   出版者・発行元：BioMed Research International  

Streptococcus pneumoniae (S. pneumoniae) is the important pathogen that causes otolaryngeal diseases such as sinusitis. S. pneumoniae frequently forms the biofilm to prevent severe circumstances such as antimicrobial agents. Shin'iseihaito (xinyiqingfeitang) is a formula of Japanese traditional Kampo medicine that has 9 crude drugs and provides the medicinal usage for sinusitis. The objective of the present study is to reveal the mechanism of antibiofilm activity by Shin'iseihaito extract (SSHT). SSHT significantly inhibited the formation of biofilm from S. pneumoniae ATCC 49619 in dose- and time-dependent manners. SSHT also significantly suppressed the biofilm formation by other five different cps types of S. pneumoniae clinical isolates. We found that the extracts of 8 out of 9 components in Shin'iseihaito had the inhibitory effects of biofilm formation, and the extract of the root of Scutellaria baicalensis had the strongest effect among the ingredients of Shin'iseihaito. We found that the capsule of SSHT-treated S. pneumoniae was significantly thinner than that of the untreated group and that SSHT reduced the hydrophobicity of bacterial cell surface. Our results suggest that Shin'iseihaito may be a useful agent for the treatment of S. pneumoniae-induced sinusitis because of the inhibition of biofilm formation of S. pneumoniae.

DOI： 10.1155/2017/4575709

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記述言語：日本語   出版者・発行元：Journal of Traditional and Complementary Medicine  

Shin'iseihaito (Magnolia Flower Lung-Clearing Decoction; 辛夷清肺湯 xīn yí qīng fèi tāng), a formula of traditional Japanese kampo medicine (日本漢醫 rì běn hàn yī) and traditional Chinese medicine (TCM; 中醫 zhōng yī), has been used for the treatment of chronic sinusitis. The objective of this study was to evaluate the anti-allergic effect of shin'iseihaito on murine allergic reaction induced by nasal sensitization using ovalbumin (OVA) as an antigen. Extract of shin'iseihaito (SSHT) could reduce the eosinophil, serum IgE and interleukin (IL)-4 levels, while increased the interferon (IFN)-γ levels in allergic mouse. Furthermore, allergic-murine serum treated with SSHT could not activate passive cutaneous anaphylaxis (PCA) reaction in murine model. Thus, our study showed that SSHT may possess anti-allergic activity. We suggested that SSHT may contribute to inhibit the exacerbation of allergic reaction induced by nasal sensitization.

DOI： 10.1016/j.jtcme.2015.06.001

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記述言語：日本語   出版者・発行元：Journal of Infection and Chemotherapy  

We report an immunocompromised child who experienced two episodes of bacteremia due to Streptococcus pyogenes. Random amplification of polymorphic DNA profiles, emm genotypes, superantigen profiles, antimicrobial susceptibility, and resistance-related genes were investigated, and the results showed different profiles between the two isolates. This is the first report describing recurrent bacteremia caused by different strains of S. pyogenes.

DOI： 10.1016/j.jiac.2015.12.014

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>我々は、Sr同位体比(⁸⁷Sr/⁸⁶Sr)を指標とした、農作物・考古学試料(土器・骨など)の産地・生育地推定を目指し、＜180 ?mの細粒河川堆積物を用いた広域Sr同位体比分布図の作成を進めてきた。これまで、Sr同位体比分布図には、背景地質の違いを忠実に反映した変動が認められることを報告してきた。しかし、岩石の代わりに河川堆積物を用いること(風化における同位体比分別問題)、細粒砂を試料に用いること(粒度問題)、動植物組織へのSr取り込み過程時の同位体比分別、など実際に起源分析に適応する前に、解決すべき問題が多く残されていた。そこで、本研究では、花崗岩、堆積岩、安山岩、変成岩など様々な岩種が出現する松山地方重信川水系を例に、河川水・湧水や粒度別に分けた河川堆積物試料を対象に、背景地質の影響、粒径効果、可溶性成分と溶存性成分のSr同位体比の関係などについて詳細な検討を行った。</p>

DOI： 10.14862/geochemproc.63.0_182

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>水試料の溶存無機炭素(DIC)の炭素同位体分析を行うにあたっては，生物活動による同位体比の変化を抑えるため，毒物添加が一般的である．しかし，管理された研究区域以外では，毒物の使用が困難な場合が多く，その他の生物活動の影響を排除する手法が必要である．ここでは，いくつかの手法の有効性について検証した結果を報告する．</p>

DOI： 10.14862/geochemproc.63.0_73

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記述言語：日本語   出版者・発行元：Pharmacognosy Journal  

Objective: Shin'iseihaito (Xin yi qing fei tang in Chinese, SSHT), a formula in traditional Japanese Kampo medicine and Chinese medicine comprising nine crude drugs, Gypsum, Ophiopogon Tuber, Scutellaria Root (SR, root of Scutellaria baicalensis), Gardenia Fruit, Anemarrhena Rhizome, Lilium Bulb, Magnolia Flower, Loquat Leaf, and Cimicifuga Rhizome, is commonly used to treat sinusitis associated with purulent nasal discharge and reddish nasal mucosa. We evaluated anti-bacterial activity of SSHT extract on Streptococcus pneumoniae, the major cause of bacterial sinusitis. Materials and Methods: Sterile paper disks impregnated with SSHT extract or each extract of its component were placed on sheep blood agar plates inoculated with Streptococcus pneumoniae (ATCC 49619). The diameter of inhibitory zone was measured after 20-24 h incubation. Results: SSHT extract and each water extract of Ophiopogon Tuber, SR, Gardenia Fruit, Anemarrhena Rhizome, Lilium Bulb, Magnolia Flower, and Cimicifuga Rhizome showed significant antibacterial activity against Streptococcus pneumoniae, and SR extract exhibited the largest inhibitory zone. SR extract was partitioned into AcOEt, BuOH, and water layer, and water layer was further separated into 80% EtOH soluble and insoluble fraction. Among them, only 80% EtOH soluble fraction was exhibited antibacterial activity. In this fraction, we found baicalin as the major compounds, and baicalin exhibited antibacterial activity against Streptococcus pneumoniae in concentrationdependent manner. Conclusion: SSHT has antibacterial activity against Streptococcus pneumoniae, and SR and its major constituent baicalin contribute to the antibacterial activity of SSHT against Streptococcus pneumoniae.

DOI： 10.5530/pj.2016.1.4

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

水試料にSrCl2等を添加して炭酸塩の沈殿を生じさせ、沈殿に酸を添加してCO2を抽出する方法（沈殿法）は数mg/Lから数千mg/Lという幅広いDIC濃度を示す陸水を扱う際に便利であり、また、沈殿生成まで行なっておけば、CO2抽出は後でまとめて可能なため、多試料のルーチン分析に適する利点がある。しかし、沈殿法は、沈殿成長に時間を要するため、化学処理に時間がかかるうえ、塩分の多い海水など、水試料の化学組成によっては沈殿が生成しにくく、炭素回収率が低いことがあるという欠点を有している。そこで、本研究においては、炭素回収率が低い原因を明らかにするとともに、14Cならびにδ13C分析値に与える影響について調べた。その結果、水試料中のCa、MgイオンがSrCO3沈殿生成を阻害していること、また、海水においてはSrSO4の沈殿が大量に生成しており、硫酸イオンが沈殿生成を阻害している可能性が示唆された。

DOI： 10.14862/geochemproc.62.0_293

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記述言語：日本語   出版者・発行元：African Journal of Traditional, Complementary and Alternative Medicines  

Background: Streptococcus pneumoniae (pneumococcus) causes various serious diseases including sinusitis, pneumonia, and meningitis. One serious problem observed recently with pneumococcal therapy is attenuation of the antibiotic effect because of the emergence of antibiotic-resistant pneumococcus. Shin’iseihaito, a traditional Japanese medicine based on ancient Chinese medicine, has been used for treatment of otolaryngeal diseases in Japan. The objective of this study was to examine the anti-infectious effects of shin’iseihaito and its related mechanism. Materials and Methods: We evaluated the beneficial effect of shin’iseihaito extract (SSHT) against pneumococcus-infected murine model. The colonization of bacteria, blood and bronchoalveolar lavage (BAL) killing activity, the levels of inflammatory cytokine and IgA were investigated. Results: The pneumococcus from blood was not found in both SSHT-treated mice and untreated mice. However, the pneumococcal colonization of lung was significantly (p<0.05) lower after SSHT administration compared with untreated mice. Blood bactericidal assay showed that no significant difference (p=0.07) was observed in the anti-bacterial effect between SSHT-treated mice and untreated mice. However, BAL bactericidal assay showed that the survival rate of pneumococcus using the BAL from SSHT-treated mice was significantly (p<0.05) lower than that using the BAL from untreated mice. We also found increased levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IgA in pneumococcus-infected mice treated with SSHT. Conclusions: SSHT decreased the colonization rate after pneumococcal infection and up-regulated BAL bactericidal activity through modulation of inflammatory cytokines and IgA. Our data also suggest SSHT may be useful for the treatment of pneumococcal infection.

DOI： 10.4314/ajtcam.v12i6.13

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記述言語：日本語   出版者・発行元：Journal of Infection and Chemotherapy  

The aim of this study was to assess the efficacy, safety, and concentration of meropenem in cerebrospinal fluid when meropenem (2 g every 8 h) was administered to Japanese adult patients with bacterial meningitis. Five Japanese patients (mean age 60.6 years [range 35-71]) were enrolled. Infection with Streptococcus pneumoniae (three patients), Streptococcus salivarius (one patient), and Staphylococcus aureus (one patient) was confirmed by cerebrospinal fluid culture. Meropenem (2 g every 8 h) was administered to all five patients. Treatment duration ranged from 14 to 28 days (mean 22.6 days). All the patients were successfully treated. The concentration of meropenem in cerebrospinal fluid ranged from 0.27 to 6.40 μg/ml up to 8.47 h and was over 1 μg/ml 3 h after starting meropenem infusion. In each patient, the present study confirmed for the first time that the concentration of meropenem in cerebrospinal fluid exceeded the minimal inhibitory concentration for these pathogens. Eleven clinical and laboratory adverse events considered to be related to meropenem were observed in all patients, but no serious adverse event and no discontinuance of treatment due to adverse events occurred. Thus meropenem appeared to be a well-tolerated and effective agent for Japanese adult patients with bacterial meningitis. 2 g every 8 h of meropenem was delivered to CSF and its concentration was exceed in MICs for the detected pathogens. © 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jiac.2014.04.013

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記述言語：日本語   出版者・発行元：PLoS ONE  

Previous studies have revealed the association between SNPs located on human leukocyte antigen (HLA) class II genes, including HLA-DP and HLA-DQ, and chronic hepatitis B virus (HBV) infection, mainly in Asian populations. HLA-DP alleles or haplotypes associated with chronic HBV infection or disease progression have not been fully identified in Asian populations. We performed trans-ethnic association analyses of HLA-DPA1, HLA-DPB1 alleles and haplotypes with hepatitis B virus infection and disease progression among Asian populations comprising Japanese, Korean, Hong Kong, and Thai subjects. To assess the association between HLA-DP and chronic HBV infection and disease progression, we conducted high-resolution (4-digit) HLA-DPA1 and HLA-DPB1 genotyping in a total of 3,167 samples, including HBV patients, HBV-resolved individuals and healthy controls. Trans-ethnic association analyses among Asian populations identified a new risk allele HLA-DPB1*09:01 (P = 1.36x10-6; OR = 1.97; 95% CI, 1.50-2.59) and a new protective allele DPB1*02:01 (P = 5.22x10 -6; OR = 0.68; 95% CI, 0.58-0.81) to chronic HBV infection, in addition to the previously reported alleles. Moreover, DPB1*02:01 was also associated with a decreased risk of disease progression in chronic HBV patients among Asian populations (P = 1.55x10-7; OR = 0.50; 95% CI, 0.39-0.65). Trans-ethnic association analyses identified Asian-specific associations of HLA-DP alleles and haplotypes with HBV infection or disease progression. The present findings will serve as a base for future functional studies of HLA-DP molecules in order to understand the pathogenesis of HBV infection and the development of hepatocellular carcinoma. © 2014 Nishida et al.

DOI： 10.1371/journal.pone.0086449

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記述言語：日本語   出版者・発行元：Coastal Engineering Journal  

At 14:46 local time on March 11, 2011, a magnitude 9.0 earthquake occurred off the coast of northeast Japan. This earthquake generated a tsunami that struck Japan as well as various locations around the Pacific Ocean. With the participation of about 300 researchers from throughout Japan, joint research groups conducted a tsunami survey along a 2,000 km stretch of the Japanese coast. More than 5,200 locations have been surveyed to date, generating the largest tsunami survey dataset in the world. The inundation height and run-up height were surveyed by laser, GPS, and other instruments, and the tidal correction has been accurately adjusted using a tidal database and a numerical simulation for Tohoku, an area where tide gauges were destroyed by the tsunami. Based on the survey dataset, the regional and local scale analyses were conducted to understand the basic characteristics of this event. Maximum run-up heights greater than 10 m are distributed along 500 km of coast in direct distance. The affected area of this event was several times larger than historically recorded in Tohoku. The mean inundation height in the southern Sanriku region is 1015 m and there are several peaks of inundation along the coast from the northern to middle part of Sanriku. © 2012 World Scientific Publishing Company and Japan Society of Civil Engineers.

DOI： 10.1142/S0578563412500015

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記述言語：日本語   出版者・発行元：Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS  

The aim of this research is to develop an information support system for tele-auscultation. In auscultation, a doctor requires to understand condition of applying a stethoscope, in addition to auscultatory sounds. The proposed system includes intuitive navigation system of stethoscope operation, in addition to conventional audio streaming system of auscultatory sounds and conventional video conferencing system for telecommunication. Mixed reality technology is applied for intuitive navigation of the stethoscope. Information, such as position, contact condition and breath, is overlaid on a view of the patient's chest. The contact condition of the stethoscope is measured by e-textile contact sensors. The breath is measured by a band type breath sensor. In a simulated tele-auscultation experiment, the stethoscope with the contact sensors and the breath sensor were evaluated. The results show that the presentation of the contact condition was not understandable enough for navigating the stethoscope handling. The time series of the breath phases was usable for the remote doctor to understand the breath condition of the patient. © 2013 IEEE.

DOI： 10.1109/EMBC.2013.6610583

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記述言語：日本語   出版者・発行元：Radiocarbon  

To study the effect of ultrafiltration on the radiocarbon ages of relatively poorly preserved bones in Japan, we analyzed the 14C dates of high-molecular-weight (HMW) gelatin samples and compared them with those of other extracted organic fractions, unfiltered gelatin samples extracted from NaOH-treated or NaOH-untreated collagen, and XAD-purified hydrolysates of animal fossil bones (~4600 BP; gelatin yield of 2-4%) from the Awazu underwater archaeological site, Shiga, Japan. NaOH-treated, unfiltered gelatins and XAD-purified hydrolysates showed statistically similar 14C ages to those of HMW gelatins. The 14C ages of the HMW gelatins were the oldest and similar to those of wood collected from the same layer as the bones, and the NaOH-treated, unfiltered gelatins gave 14C ages within the acceptable margins of error; therefore, ultrafiltration was effective for accurate 14C dating, while NaOH-treated gelatin without ultrafiltration was also sufficient to obtain accurate 14C dates on the animal bones. The 14C ages of human skeletons (~750 BP; gelatin yield of 2-11%) from 5 individuals excavated from an archaeological site in Yuigahama, Kamakura, Japan, showed statistically the same 14C ages as NaOHtreated, unfiltered gelatins and HMW gelatins within the margins of error, although HMW gelatins were likely to give slightly older ages than unfiltered gelatin with a yield of less than ~3%. These results indicate that unfiltered gelatins extracted from fossil bones of gelatin yield more than ~3% can produce accurate 14C ages without the need for ultrafiltration. Ten bone fragments from 3 humans showed the same 14C ages for each individual, suggesting that any bone part from an individual can be used to obtain a representative age. The 14C ages of tooth enamels of 2 individuals were 35 and 70 yr older than their bone ages. Death dates obtained from these age gaps agreed with those determined by morphology. © 2013 by the Arizona Board of Regents on behalf of the University of Arizona.

DOI： 10.2458/azu_js_rc.55.16334

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記述言語：日本語   出版者・発行元：Limnology  

We describe the limnological features of six glacier-fed rivers located at an altitude of over 4,000 m in Southern Tibetan Plateau, China, based on diurnal observations of the water environment and biota in the summer of 2010. The rivers showed significant diurnal changes in water level, temperature, and turbidity; clear and cool streams in the morning changed to cloudy rapid flow in the afternoon, and water temperature was elevated under strong light conditions where riparian forest did not cover the surface of the water. On the other hand, the pH and dissolved oxygen saturation did not show any diurnal fluctuations, which indicates low periphytic algal productivity. The aquatic insect communities were poor both in diversity and density, and the dominant life forms (from a functional feeding group perspective) were collectors, which depend on allochthonous organic matter; scrapers, which depend on autochthonous algal production, were scarce. We therefore suggest that diurnal or seasonal high waters transport products from marginal pools along dried riverbeds or from ponds on flood plains, and may serve as the source of organic matter in glacier-fed rivers. © 2012 The Japanese Society of Limnology.

DOI： 10.1007/s10201-012-0378-4

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記述言語：日本語   出版者・発行元：Pathology International  

Invasive diseases such as toxic shock syndrome caused by Streptococcus pyogenes (S. pyogenes) are re-emerging infectious diseases. The mechanism of pathogenesis is not completely understood although the virulence of this organism has been analyzed using animal model systems, particularly using mice. The analysis of the progression of infection, however, is difficult. Computed tomography (CT) scanning is an extremely powerful technique that we applied to the mouse model of cutaneous infection with S. pyogenes. Two or three days after subcutaneous administration of bacteria, high density reticular areas were detected in the lung by CT. Histopathological examination of the lung was performed to examine the results of CT. Increased numbers of cytokeratin-positive epithelial cells, probably alveolar type II epithelial cells, were detected but no remarkable increase of inflammatory cell infiltrates was observed. Our results show that the pathological lesions of the lung in this model, wherein relatively few numbers of neutrophils were in the alveoli, are well correlated with the lung of a part of streptococcal toxic shock syndrome patients. Therefore, CT may be useful in assessing the progression of S. pyogenes infection, particularly in the pathological lesions of the lung in this model. © 2011 The Authors. Pathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.

DOI： 10.1111/j.1440-1827.2011.02756.x

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記述言語：日本語   出版者・発行元：Radiocarbon  

We investigated the radiocarbon ages and carbon and nitrogen isotope ratios of human skeletal remains from burials at the Yuigahama-minami and Chusei-Shudan-Bochi sites in the Yuigahama area (Kamakura, Japan), which we believe are associated with the great attack on Kamakura by Nitta Yoshisada in AD 1333. The human bones produced enriched δ13C and δ15N values that could be affected by consumption of protein from marine fish and/or mammals with high δ13C and δ15N, and therefore older apparent 14C ages. We thus estimated the marine reservoir effect on human skeletons to determine their true ages. The IsoSource isotope mixing model was employed for reconstructing percentages of marine protein in the human diet, and calibrated calendar dates for the 14C ages were calculated using the marine percentages. At the Yuigahama-minami site, most skeletons from individual burials now date to the last phase of the Kamakura period or the early part of the Muromachi period, while skeletons from mixed human-animal multiple burials date to the latter part of the Kamakura period. The humans from the individual burials, consisting of normal ratios of adult males, could have died a natural death, though the site could also have been used to inter victims of the battle of 1333. The humans from mixed human-animal burials, consisting of a high proportion of infants, were not victims of the 1333 battle, but the site may have been used to inter victims of the Kamakura earthquake in 1293, which resulted in a catastrophic tsunami. On the other hand, the skeletons from multiple burials in the Chusei-Shudan-Bochi site all date to the middle Kamakura period. Coupled with the fact that most humans in the site are male but show no evidence of injuries by sword cuts, it is likely that burials of the Chusei-Shudan-Bochi site could have been a collective interment following the Jinji earthquake in 1241, the Shoka earthquake in 1257, or the Shoka famine in 1258 in the middle Kamakura period. The results of this study indicate that humans from burials in the Yuigahama region were not necessarily victims of the attack by Nitta Yoshisada on Kamakura, but instead were likely victims of natural disasters such as large earthquakes and severe famines, which often occurred in the middle Kamakura period. © 2012 by the Arizona Board of Regents on behalf of the University of Arizona.

DOI： 10.1017/s0033822200047287

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記述言語：日本語   出版者・発行元：Microbiology  

The virulence of Streptococcus pyogenes depends on proteins that are produced by this bacterium. The production of virulence proteins depends on environmental factors, and two-component regulatory systems are considered to be involved in sensing these factors. One of the environmental factors is acid stimuli. We established knockout strains in all speculated two-component regulatory sensor proteins of the M1 clinical strain of S. pyogenes and examined their relevance to acid stimuli. The parental strain and its derived knockout strains were cultured in a medium adjusted to pH 7.6 or 6.0, and their growth in broth was compared. The spy1622 sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1622 two-component sensor protein is involved in sensing acid stimuli. To further examine the role of the Spy1622 two-component sensor protein in virulence, blood bactericidal assays and mouse infection model experiments were performed. We found that the spy1622 knockout strain was less virulent than the parental strain, which suggests that the Spy1622 two-component sensor protein could play an important role in virulence. © 2011 SGM.

DOI： 10.1099/mic.0.050534-0

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記述言語：日本語   出版者・発行元：PLoS ONE  

Background: Streptococcus pyogenes (S. pyogenes) causes various serious diseases including necrotizing fasciitis and streptococcal toxic shock syndrome. One serious problem observed recently with S. pyogenes therapy is attenuation of the antibiotic effect, especially penicillin treatment failure and macrolide resistance. Hainosankyuto, a traditional Japanese medicine based on ancient Chinese medicine, has been used for treatment of infectious purulent diseases in Japan. In this study, we investigated the protective and therapeutic efficacy of Hainosankyuto against S. pyogenes-skin infection. Methodology/Principal Findings: A broth microdilution method revealed that Hainosankyuto did not show a direct anti-bacterial effect against S. pyogenes. Force-feeding Hainosankyuto to infected mice for 4 consecutive days increased the survival rate and reduced the size of local skin lesions compared with mice fed PBS. Although we did not find the significant recovery of survival rate in Hainosankyuto administration only after S. pyogenes infection, the sizes of ulcer lesion were significant smaller after Hainosankyuto administration compared with mice fed PBS. No difference was observed in the anti-bacterial effect of Hainosankyuto between macrolide-susceptible and -resistant strains. Blood bactericidal assay showed that the survival rate of S. pyogenes using the blood from Hainosankyuto -treated mice was lower than that using the blood from untreated mice. We also found increased levels of IL-12, IFN-γ and a decreased level of TNF-α in the serum of S. pyogenes-infected mice treated with Hainosankyuto. Mouse peritoneal macrophage from Hainosankyuto-treated mice had significant phagocytic activity and increased mRNA levels of IL-12, IFN-γ and decreased mRNA level of TNF-α compared with control macrophage. Conclusions/Significance: Hainosankyuto increased survival rate after S. pyogenes infection and up-regulated both blood bactericidal activity and macrophage phagocytic activity through modulation of inflammatory cytokines. Our data also suggest Hainosankyuto may be useful for the treatment of S. pyogenes infection more prophylactically than therapeutically. © 2011 Minami et al.

DOI： 10.1371/journal.pone.0022188

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記述言語：日本語   出版者・発行元：Kansenshōgaku zasshi. The Journal of the Japanese Association for Infectious Diseases  

We determined temporary changes in group B Streptococcus antimicrobial susceptibility and serotype distribution from perinatal strains. We examined invasive microbiological isolates from neonates with early-onset group B streptococcal disease (n = 14), and colonized isolates from those born uneventfully (n = 55) and from the genital tracts of pregnant and puerperal women (n = 198), collected between 1999 and 2009. All isolates were susceptible to penicillin. No significant differences were seen in susceptibility of 12 antimicrobial agents examined between invasive and colonized isolates. MIC50, MIC90, and resistance did not differ between stage I (1999-2005) and II (2006-2009) isolates. Serotype distribution significantly differed, however, serotypes III and Ia predominated among invasive isolates, while serotypes Ib and VI were common among their colonized counterparts. These findings suggest that to date, penicillin remains effective in intrapartum prophylactic use in colonized pregnant women.

DOI： 10.11150/kansenshogakuzasshi.85.155

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記述言語：日本語   出版者・発行元：Radiocarbon  

A new continuous sediment core (PY608W-PC; 3.8 m length) for reconstruction of climatic and environmental changes in the southeastern Tibetan Plateau was taken from the eastern part of Lake Pumoyum Co in August 2006. Sediment layers of the lower part of PY608W-PC (380-300 cm depth) were composed mainly of relatively large plant residues (up to ~3 cm in length) with an admixture of fine sand and sandy silt. The large plant residues disappeared at ~300-290 cm depth in core PY608W-PC and were replaced by silt-silty clay. The large plant residues from the lower part of PY608W-PC could be aquatic, because the plant residues were extremely enriched in 13C (up to -3.0‰, -5.6 ± 2.3‰ on average). On the other hand, the plant residue concentrates (PRC fractions) from the upper part of the core (290-0 cm in depth) could be terrestrial C3 plants (δ13C = -21.8 ± 1.7‰ on average). Radiocarbon dating was performed on the large plant residues and PRC fractions from the PY608W-PC sediment core, which represented the chronology from ~19,000 cal BP to present. © 2010 by the Arizona Board of Regents on behalf of the University of Arizona.

DOI： 10.1017/S0033822200046518

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記述言語：日本語   出版者・発行元：Current Microbiology  

Streptococcus pyogenes is indigenous to the human pharynx and causes acute pharyngitis. Balanoposthitis is an inflammatory disease of the glans and the foreskin. However, balanoposthitis caused by S. pyogenes is not widely recognized as a sexually transmitted disease. In addition, bacteriological features of the isolates causing balanoposthitis are unclear. The four S. pyogenes strains isolated from adult balanoposthitis were examined. We performed emm typing, T antigen typing, RAPD assay, PCR assay for the streptococcal pyrogenic exotoxin-related genes and antibiotic-resistant genes, and antibiotic susceptibility assay. All four strains were suspected to be transmitted by penile-oral sexual intercourse, were found to be different by genetic analysis, and also harbored some antibiotic-resistant factors. We propose that S. pyogenes should be considered as a causative agent of sexually transmitted disease. The drug resistant S. pyogenes must be taken into account when balanoposthitis patients are treated with antibiotic. © 2010 Springer Science+Business Media, LLC.

DOI： 10.1007/s00284-010-9581-x

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記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

For combustion of organic samples, a closed tube-combustion (CTC) method is generally used, but this method requires much time and labor. The AMS facility at the Center for Chronological Research, Nagoya University, has established a CO2 production and purification system using an elemental analyzer (EA) connected to cryogenic traps. This system enables faster combustion and CO2 purification of samples than does the conventional CTC method. We compared measured carbon yields, δ13C values and 14C activities between EA and CTC samples of carbon standards of various sample quantities. This newly developed EA system had low background 14C activity due to sample preparation; the background activity was similar to that observed for the CTC method. The EA system also showed high precision and accuracy for δ13C and 14C measurements. The EA sample data obtained from conventional quantities (>1 mg carbon) of standards showed good agreement with the results obtained by the CTC method and with the consensus values, though background contamination was detected for samples containing <0.5 mg carbon. Oxalic acid standards containing <0.5 mg carbon that were analyzed by the CTC method tended to have widely varying values of carbon yield, δ13C and 14C activity, suggesting that the CO2 produced by combustion might have been prone to adsorption to an inner wall of the combustion tube, to CuO or to both, and that the CO2 produced in the CTC method might have decomposed. © 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2009.10.063

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記述言語：日本語   出版者・発行元：APMIS  

Streptococcal toxic shock syndrome (STSS) is a re-emerging infectious disease in Japan and many other developed countries. Epidemiological studies have revealed that the M1 serotype of Streptococcus pyogenes is the most dominant causative isolate of STSS. Recent characterization of M1 isolates revealed that the mutation of covS, one of the two-component regulatory systems, plays an important role in STSS by altering protein expression. We analyzed the M1 S. pyogenes clinical isolates before or after 1990 in Japan, using two-dimensional gel electrophoresis (2-DE) and pulsed-field gel electrophoresis (PFGE). PFGE profiles were different between the isolates before and after 1990. Markedly different profiles among isolates after 1990 from STSS and pharyngitis patients were detected. Sequence analysis of two-component regulatory systems showed that covS mutations were detected not only in STSS but also in three pharyngitis isolates, in which proteins from the culture supernatant displayed the invasive type. The mutated CovS detected in the pharyngitis isolates had impaired function on the production of streptococcal pyrogenic exotoxin B (SpeB) analyzed by 2-DE. These results suggest that several covS mutations that lead to the malfunction of the CovS protein occurred even in pharyngeal infection. © 2010 APMIS.

DOI： 10.1111/j.1600-0463.2009.02574.x

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記述言語：日本語   出版者・発行元：BMC microbiology  

BACKGROUND: NAD-glycohydrolase (NADase) secreted by M-1 group A streptococcal (GAS) isolates are suspected as one of the virulence factors to cause severe invasive disease including streptococcal toxic shock-like syndrome (STSS). M-1 GAS strains were divided into three groups based on NADase activity: high activity, low activity and no activity in our previous report. RESULTS: The representative high activity isolates taken from STSS patients showed higher virulence compared with isolates from the low activity group, when used to infect mice. The knockout mutant of the nga gene, which encodes NADase also showed reduced virulence in a mouse infection study. The cloned nga gene was able to significantly complement the lost virulence. In addition, the solution containing purified recombinant IFS, which is an inhibitor of NADase, partially rescued mice infected with S. pyogenes. CONCLUSIONS: These results indicate that NADase is important for the virulence of S. pyogenes in vivo and is the potential target to suppress the virulence.

DOI： 10.1186/1471-2180-10-144

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記述言語：日本語   出版者・発行元：FEMS Microbiology Letters  

Streptococcus salivarius inhibits the growth of Streptococcus pyogenes in vitro. Streptococcus pyogenes has various virulence factors, including the streptococcus inhibitor of complement (SIC). Although SIC inhibits the activity of the peptides LL-37 and NAP1, the relationship between SIC and the bacteriocin-like inhibitory substance (BLIS) has not been elucidated. Here, we evaluated whether S. salivarius BLIS affects S. pyogenes SIC. We created three Δsic mutant strains from three S. pyogenes strains and performed deferred antagonism assays. The test strains were BLIS-positive S. salivarius JCM5707 and BLIS-negative S. salivarius NCU12. Deferred antagonism assays with JCM5707 showed that the inhibitory zones in the three Δsic mutant strains were wider than those in the three wild-type strains. Streptococcus pyogenes was cultured in BLIS-containing broth and the change in SIC in the supernatant was assessed by two-dimensional gel electrophoresis (2-DE). The 2-DE analysis of S. pyogenes exoproteins with the JCM5707 supernatant showed reduced SIC compared with those without the JCM5707 supernatant. Changes in sic mRNA levels affected by S. salivarius BLIS were evaluated by a reverse transcriptase-PCR. The sic mRNA level was affected more by the BLIS-positive S. salivarius than by the BLIS-negative strain. Our result indicates that SIC plays a role in the inhibition of S. salivarius BLIS. © 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

DOI： 10.1111/j.1574-6968.2009.01696.x

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記述言語：日本語   出版者・発行元：IEEJ Transactions on Power and Energy  

This paper describes the results of the experiments of wind turbine blades with rocket triggered lightning. A number of wind power stations have been projected and planted. Lightning damage to wind turbines has been an increasing problem recently. So development on protection of wind power plants from lightning is necessary to be fully run for the future. In the experiments, the 1.8 m long blade was struck by the lightning discharge triggered by rocket. For the blade kept dry inside, the very strong discharge of positive peak current 28 kV, total charge 520 Coulombs, was triggered, but the breakdown did not occur through the blade into inside. Another blade polluted by salty wet inside was struck by the lightning discharge of negative peak current of 4kA with 0.5 Coulombs. The lightning was small, nevertheless, the blade was broken at the upper edge and the blade was disconnected by crack. For the protection of blade, the blade surface was covered with stainless steel plate. The blade itself was safe when the big positive lightning discharged, while most part of stainless steel cover was burned out. Supplement breakdown tests of wind turbine blade were carried out with lightning impulse voltage in laboratory. As a result, it became clear that the blade kept dry inside was an effective lightning protection of wind turbine blades. © 2009 The Institute of Electrical Engineers of Japan.

DOI： 10.1541/ieejpes.129.689

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記述言語：日本語   出版者・発行元：Hepato-Gastroenterology  

Background/Aims: Crohn's disease is often refractory and some patients require repeated surgical treatment. Nutritional therapy with an elemental diet has been reported effective in improving nutritional state and suppressing inflammation, and might be expected to assist in minimizing the need for surgery. We evaluated the relationship between an elemental diet and the period that patients spent without intestinal resection. Methodology: A total of 153 patients with Crohn's disease who visited our hospital from July, 1999 to July, 2005 were enrolled. The relationship between the caloric content of an elemental diet and surgery as an endpoint was examined using Cox regression analysis. Cumulative non-operation rates were calculated by the Kaplan-Meier method. Statistical significance was determined using the log-rank test. Results: Among patients with jejunoileal involvement, patients receiving an elemental diet providing 900 kcal or more per day showed a statistically significant improvement in cumulative non-operation rate. Among those without jejunoileal involvement, in contrast, the cumulative non-operation rate did not differ among those receiving an elemental diet of less or more than 900 kcal per day. Conclusions: The use of an elemental diet of 900 kcal per day may be effective in avoiding surgery in patients with jejunoileal lesions. This diet may be useful in improving long-term convalescence in these patients. © H.G.E. Update Medical Publishing S.A.

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DOI： 10.1016/j.ijid.2008.05.702

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記述言語：日本語   出版者・発行元：Hepato-Gastroenterology  

A 73-year-old woman presented with massive bloody stools while undergoing hospitalization for multiple myeloma. Colonoscopy and transrectal double-balloon enteroscopy revealed multiple punched-out ulcers throughout the entire colon and in the distal ileum. Cytomegalovirus was detected in the biopsy specimens of both the colonic and ileal mucosa and in the peripheral blood, which lead the diagnosis of CMV enterocolitis. The patient's gastrointestinal bleeding was temporarily improved by the administration of ganciclovir, though she died thereafter due to progression of the primary disease. We herein report the effectiveness of transrectal double-balloon enteroscopy for the diagnosis of cytomegolo-virus enterocolitis. © H.G.E. Update Medical Publishing S.A., Athens-Stuttgart.

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記述言語：日本語   出版者・発行元：General Thoracic and Cardiovascular Surgery  

Thymoma and thymic carcinoma are the representative tumors arising from the thymic epithelium. Thymoma is well known for association with autoimmune diseases including myasthenia gravis, suggesting its biological activity. Herein, recent progress in research of thymoma is reviewed with reference to its immunological function. Myasthenia gravis is frequently associated with WHO type B1 and B2 thymomas. These types of thymomas hold a significant number of CD4+CD8+ double-positive T cells, and at the same time, the neoplastic epithelial cells express HLA-DR molecules at a slightly reduced level compared with the normal thymus. The impaired expression of HLA-DR molecules in neoplastic epithelial cells of thymomas possibly affects positive selection of CD4+CD8- single-positive T cells and may result in alteration of its repertoire. The function of thymoma neoplastic cells as the cortical epithelium of the thymus and the morphological resemblance of thymomas to the cortex suggest that thymoma is of cortical epithelial origin; this might imply that thymoma lacks the functional medulla where professional antigenpresenting cells are engaged in negative selection. These findings suggest that thymoma generates autoreactive T cells causing autoimmunity. Further investigation on immunological function of thymoma is supposed to elucidate the pathogenesis of thymoma-related autoimmunity and the high affinity of thymoma with myasthenia gravis. In addition, studying the biology of thymoma is also expected to contribute to further understanding of T-cell development and immunological tolerance in the human, because thymoma can be considered an acquired thymus. © 2008 The Japanese Association for Thoracic Surgery.

DOI： 10.1007/s11748-007-0185-8

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記述言語：日本語   出版者・発行元：Microbiology  

The NADase (Nga) of group A streptococci (GAS) has been implicated in the pathogenesis of diseases such as streptococcal toxic shock-like syndrome (STSS) and necrotizing fasciitis. In this study we found that the proportion of NADase-positive strains among clinical isolates in Japan has increased over time. The GAS strains studied could be divided into three groups: strains lacking NADase activity, strains with low NADase activity, and strains with high NADase activity. The older strains, isolated before 1989, belonged to the 'no activity' group. Analysis using GST-Nga recombinants revealed that nga alleles of representative older strains encode inactive Nga. Mutational analysis of the GST-Nga recombinants suggested that residue 330 could be associated with reduced activity, based upon deduced amino acid sequences. We also investigated NADase activity of streptococcal strains other than GAS. All group G streptococcal isolates from STSS patients possessed nga genes encoding active enzymes. © 2007 SGM.

DOI： 10.1099/mic.0.2007/009555-0

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記述言語：日本語  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

We tried to estimate paleotemperatures from two chosen fossils by measuring d/l aspartic acid ratios and radiocarbon ages of the XAD-2-treated hydrolysate fractions in the fossils. The d/l aspartic acid ratio was measured with a gas chromatograph and radiocarbon dating was performed using a Tandetron AMS system at Nagoya University. The radiocarbon age of a fossil mammoth molar collected from Bykovsky Peninsula, eastern Siberia, was found to be 35,170 ± 300 BP as an average value for the XAD-treated hydrolysate fractions. The aspartic acid in the mammoth molar showed a little evidence of racemization, which might be due to in vivo racemization during the lifetime and then suggests negligible or no postmortem racemization during burial in permafrost. From four animal bone fossils collected from a shell mound excavated at the Awazu submarine archeological site in Lake Biwa, Shiga, Japan, the racemization-based effective mean temperature was calculated to be 15-16 °C using the d/l aspartic acid ratio of about 0.11 and the 14C age of 4500 BP for the XAD-2-treated hydrolysate fractions in the fossils. The average annual temperature was estimated to be 11-12 °C, which approximates to the temperature that the fossils experienced during burial at the site. Although the application of racemization ratios in fossils as paleotemperature indicators is surrounded with many difficulties, the results obtained in this study suggest its feasibility. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2007.01.201

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記述言語：日本語   出版者・発行元：日本建築学会  

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記述言語：日本語   出版者・発行元：Tree-Ring Research  

14C wiggle-matching was applied to two wood samples closely related to geological and archaeological events with associated dendrochronological dates, to demonstrate the accuracy of 14C dating with accelerator mass spectrometry (AMS). Wiggle-matching on charred wood with bark, excavated from a pyroclastic mud-flow deposited by the huge 10th Century eruption of the Baitoushan Volcano, revealed the eruption age as cal A.D. 935 +8/-5 with 95% confidence. This date is consistent with the eruption age of A.D. 912 to A.D. 972 estimated by dendrochronology on two wooden boards that had clear stratigraphical connections to the B-Tm tephra deposit in Japan, an ash fall layer formed by the eruption of the Baitoushan Volcano. The date is also consistent with an A.D. 937-938 date estimated by the analysis of varved sediments from Lake Ogawarako in Aomori prefecture. The other wooden board collected from the Mawaki archaeological site in Ishikawa prefecture was wiggle-matched as 783 +13/-11 cal B.C. with 95% confidence, which is consistent with the dates of 830 cal B.C. to 759 cal B.C. obtained for seven wooden poles from the same wooden structures as the wooden board. These results are highly encouraging for obtaining accurate dates on wood when dendrochronology cannot be used. Copyright © 2007 by the Tree-Ring Society.

DOI： 10.3959/1536-1098-63.1.37

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記述言語：日本語   出版者・発行元：Meteoritics and Planetary Science  

We examined an improved system for extraction of carbon from meteorites, using a vacuum-tight RF melting method. Meteorite samples mixed with an iron combustion accelerator, including a specific amount of carbon (0.052%), were combusted in a RF furnace (LECO HF-10). 14CO2 extracted from the meteorite was diluted with a known amount of nearly 14C-free CO2, evolved from the iron accelerator on combustion. The 14C activities of the recently fallen Holbrook (L6) and Mt. Tazerzait (L5) meteorites were measured by this method. The mean value was 56.5 ± 3.0 dpm/kg, which is similar to the values reported for recently fallen L6 chondrites. Furthermore, terrestrial ages were measured for four Antarctic meteorites: 1.8 ± 0.5 kyr for Yamato (Y-) 75097 (L6), 1.8 ± 0.5 kyr for Y-75108 (L6), and 0.1 ± 0.1 kyr for Y-74192 (H5). For Y-74190 (L6), an apparent age of 0.8 ± 0.5 kyr was calculated. After consideration of the shielding effect by using 22Ne/21Ne values, we obtained about 1.8 kyr for the terrestrial age of this chondrite. The five samples Y-74190, Y-75097, and Y-75108, together with Y-75102 (L6) and Y-75271 (L6), have been reported to be paired and fragments of an L-chondrite shower (Honda 1981; Takaoka 1987). The result of this work and literature data for the latter two samples confirmed that they are paired. More discussion and experimental work are needed for other recently fallen meteorites, both for L and H chondrites, and a correction for the shielding effect should be done to determine a more reliable terrestrial age. © The Meteoritical Society, 2006.

DOI： 10.1111/j.1945-5100.2006.tb00480.x

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：Tellus, Series B: Chemical and Physical Meteorology  

Diurnal variation in the atmospheric CO2 concentration and the carbon isotopic composition (Δ14C and δ13C) was measured in a forest in an urban area on 9 February 1999. The carbon isotope approach used in the present study differentiated between the quantitative contributions from anthropogenic and biogenic CO2 sources in the urban atmosphere. The anthropogenic (fossil fuel) and biogenic (soil respiration) contributions was estimated, and they ranged from 1 to 16% and from 2 to 8% of the total atmospheric CO2. The diurnal variation of the anthropogenic CO2 was the major cause of the total atmospheric CO2 variation, while the biogenic CO2 remained relatively constant throughout the day. Estimating the contribution of soil respired CO2 provided the mean residence time of soil respired CO2 within the forest atmosphere.

DOI： 10.1034/j.1600-0889.2002.00231.x

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：Schizophrenia Research  

DOI： 10.1016/S0920-9964(00)00049-9

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記述言語：日本語   出版者・発行元：Radiocarbon  

We have constructed a system to extract carbon from meteorites using a vacuum-tight RF melting method in order to study radiocarbon activities in meteorites. The extraction system was examined using iron standards of known carbon content. The carbon extraction efficiencies and 14C ages of the iron standards by this method were compared with the results obtained previously by our older melting system and a wet oxidation method. Higher collection efficiencies of about 90% for the iron samples of relatively high carbon content were achieved by the new system. The efficiency of extracting a small amount of carbon is also near 90% after improving the extraction procedure. The 14C ages of the iron standards were compared to the ages by the wet method. The results indicate that contamination by modern carbon is negligible in the system. Furthermore, terrestrial 14C ages of two Antarctic meteorites, Y-75102 and ALH-77294, from the Yamato and Allan Hills ice fields, respectively, were determined. The age of Y-75102 is estimated 4.0 ± 1.0 ka, and the age of ALH-77294 is 19.5 ± 1.2 ka. The 14C ages on the meteorites roughly agree with the literature value. However, further study is needed in improvement on reducing a background value and of complete fusion of a meteorite in the extraction system. © 2001 by the Arizona Board of Regents on behalf of the University of Arizona.

DOI： 10.1017/s0033822200038091

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記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

The XAD-2 chromatography method was examined for its ability to efficiently eliminate exogenous organic matter from fossil bones and to improve the accuracy of radiocarbon (14C) dating and stable isotope determinations on bone proteins. The fossil bones used in the experiment were animal fossil bones collected from the Awazu submarine archaeological site, Shiga, Japan. For comparison, the gelatin-extraction method was also applied to the same samples. It was found that the gelatin-extraction method is sufficient for 14C dating on well-preserved bones, but insufficient on poorly preserved bones, containing less than 1% extractable gelatin. The XAD-2 resin is useful for the clean up of proteins especially from poorly preserved bones. The carbon stable isotope fractionation of around 1‰ by XAD-2 treatment on modern collagen standards was larger than reported previously. The isotopic variation by sequential extraction of bones probably originates from changes in the amino acid composition and seems to be less sensitive to the indication of the removal of organic contamination. © 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0168-583X(00)00397-9

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記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

In 1996/97, we installed a second-generation AMS system (model 4130-AMS) manufactured by HVEE, B.V., The Netherlands. Although we encountered a lot of problems during the installation and tuning up of the machine, our new system has now reached good stability and reproducibility in performing 14C/12C and 13C/12C measurements. According to the reproducibility tests conducted in January 1999, where six graphite targets prepared from HOxII standard material were measured, the standard deviation for 14C/12C reproducibility is around 1.6%e (comparable with counting statistics) and that for 13C/12C is 0.28%e. The background level of the AMS system was measured using a pure graphite (commercial graphite rod). It lies between 50 and 55 ka BP. We are still on the way to reduce the background. However, we are now prepared to start routine measurements of unknown-age samples. © 2000 Elsevier Science B. V. All rights reserved.

DOI： 10.1016/S0168-583X(00)00398-0

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記述言語：日本語   出版者・発行元：名古屋大学  

XAD-2 resin is considered the good materials to separate quantitatively the polar amino acids from the less polar fulvic and humic acids. To evaluate if XAD-2 treatment affects isotope values, δ ^<13>C and δ ^<15>N were measured on bulk sample by a simple preparation, gelatin-collagen extracted by usual method, decalcified bone powder and XAD-purified hydrolysates from a modern well-preserved ivory sample "IVRY-1". Among three fractions of bulk, gelatin-collagen and decalcified ivory powder, there are almost no difference in both δ ^<13>C and δ ^<15>N. On the other hand, XAD-treated hydrolysate has apparently more positive δ ^<13>C and δ ^<15>N values than the three fractions. However, it is doubt whether the result is due to isotope fractionation by XAD-2 treatment because the fulvic and humic contamination in the collagen might affect isotope values of bulk, gelatin-collagen and decalcified ivory powder. The C/N ratio in fulvic and humic phases is significantly more higher than collagen. In the next study, we have to study modern collagen standards or amino acid standards to evaluate if XAD-2 resin introduce isotope fractionation.

CiNii Research

記述言語：日本語   出版者・発行元：Journal of Magnetism and Magnetic Materials  

Fitting of quadratic curves to four defined subgroups of lanthanides shows that the tetrad effects in Ln3+ ionic radii with coordination number (CN) 6 are larger than those with CN 8. The features for the first tetrad are peculiar compared with other three subgroups, with both CN. The observed facts can be explained in terms of configuration of 4f electron clouds and their interaction with ligands. © 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(97)00957-8

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記述言語：日本語   出版者・発行元：General Pharmacology  

1. Dietary docosahexaenoic acid (DHA) suppressed the age dependent increase in systolic blood pressure and prolonged the average survival time of stroke-prone spontaneously hypertensive rats (SHRSP). 2. Dietary DHA (1% and 5% in diets) altered the circadian rhythm of SHRSP, causing significant increases in ambulatory activity during the dark period. At the onset of stroke, desynchronization with light and dark phases and new biological rhythms were noted in all of the control SHRSP (DHA 0%). DHA treated SHRSP did not show such behavioral changes. 3. These effects were accompanied by the increase of DHA and the decrease of AA levels in plasma and brain cortex. 4. It was concluded that dietary DHA suppresses the development of hypertension and stroke-related behavioral changes, resulting in prolongation of the SHRSP's life span.

DOI： 10.1016/S0306-3623(96)00487-9

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記述言語：日本語   出版者・発行元：Geochemical Journal  

Here is presented a mathematical method which enables us to evaluate the degrees of lanthanide tetrad effects from the data involving all of REE. Each of the four spans corresponding to four subgroups, La-Nd, Pm-Gd, Gd-Ho, and Er-La, is approximately fitted to a quadratic function and the resultant quadratic coefficient is employed as a numerical indicator for the tetrad effect. For the purpose of approximation by a quadratic function, the least-squares method it used under the constraint that the first and second quadratic curves intersect at the middle point between Pm and Sm, and that the third and fourth ones intersect at the middle Point between Ho and Er. Since, mathematically, the subject is a problem on the conditional extremum, the method of Lagrange undetermined multipliers should be used. It is noted that the degrees of four tetrad effects can be evaluated simultancously. This method can lead us to the mathematically well-defined estimation of the tetrad effect.

DOI： 10.2343/geochemj.31.125

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記述言語：日本語   出版者・発行元：International Immunology  

A variety of cytokines induce the tyrosine phosphorylation of signal transducers and activators of transcription (STATs). Activation of the same STAT proteins by distinct cytokines and activation of different STAT proteins by each cytokine are thought to contribute to redundancy and pleiotropy of cytokine actions respectively. STAT3 is rapidly tyrosine phosphorylated in response to IL-6, ciliary neurotrophic factor, oncostatin M, leukemia inhibitory factor, IL-11, granulocyte colony stimulation factor and epidermal growth factor. In this report we have isolated and characterized the mouse genomic structure of STAT3. The mouse STAT3 gene consisted of 24 exons which spanned > 37 kb. The structure of the mouse STAT3 gene was almost identical to that of the human STAT2 gene, including the number and size of exons, indicating that the exon-intron organization had already been accomplished before these two genes duplicated, and then these genes evolved to respond to different ligands. By molecular linkage analysis with interspecific backcross mice the STAT3 gene mapped at 1.4 cM proximal to D11Mit59 on mouse chromosome 11. The promoter region contained potential regulatory elements such as GATA, NF-IL-6, PEBPP, Sp-1, AP-2 binding sites, cAMP response element, CAAT box and E-box. Transient expression of constructs harboring the 5' flanking region of the STAT3 gene fused to the luciferase gene showed that a 160 bp sequence upstream of the transcription start site conferred a basal and an IL-6-inducible promoter activity.

DOI： 10.1093/intimm/8.8.1205

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記述言語：英語   出版者・発行元：一般社団法人日本地球化学会  

Isotopic data of Sm-Nd, La-Ce and Rb-Sr systems, rare earth element (REE) abundances and major element compositions are reported for the Archean Marble Bar Chert from the Towers Formation of the Salgash Subgroup, Warrawoona Group, Pilbara Block, Western Australia. The Marble Bar Chert records two Sm-Nd ages; 3.2 ± 0.3 Ga for red (or black) and white banded cherts and 2.5 ± 0.2 Ga for yellowish gray cherts. These ages contain relatively large uncertainties and are younger than 3.45 Ga U-Pb zircon ages previously reported for the Salgash Subgroup. The results imply some later perturbation in Sm-Nd system of these cherts after their formation. However, the older age of 3.2 ± 0.3 Ga is close to the U-Pb zircon ages for the Salgash Subgroup within analytical errors and therefore can be regarded as the formation time of the banded cherts. On the other hand, the younger age of 2.5 ± 0.2 Ga for the yellowish gray cherts is thought to reflect the time of later thermal events and the cherts do not retain their original chemical features. The 3.2 Ga Sm-Nd age for the Marble Bar banded cherts is the first Archean record obtained for the Archean cherts; their initial εnd value of ±1.0 ±3.0 holds the original nature at their formation without severe geochemical disturbance. The obtained mantle-like depleted or chondritic feature at 3.2 Ga for the banded cherts, together with their Si02 and Fe2 O3 * data and positive Eu anomalies in REE patterns, suggests substantially large contribution of hydrothermal solution derived from depleted- or chondritic-mantle to the cherts and inorganic origin of the cherts, which contrasts to Phancrozoic biogenic cherts. © 1995, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

DOI： 10.2343/geochemj.29.347

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：公益社団法人 日本コンクリート工学会  

Capturing atmospheric CO2 into cement-based materials is a way to set off the CO2 emissions of concrete production. This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured. The experimental results show that the 14C value of carbonated cement paste can be used as an indicator for tracing the origin of carbon.

DOI： 10.3151/jact.21.934

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記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

DOI： 10.5575/geosoc.2022.0021

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sedimentary Geology  

Glendonite is generally accepted as a calcite pseudomorph after ikaite (CaCO3·6H2O) and is commonly preserved in spherical carbonate concretions known as glendonite concretions in marine sedimentary rocks. Although they have widely attracted attention as environmental indicators, the detailed geochemical process underlying glendonite formation is not fully understood. Here to show the glendonite concretion formation process, we conducted detailed macro- and microscopic observations, carbon and oxygen isotopic analyses (δ13C and δ18O), chemical composition analyses, and elemental mapping of glendonite concretions from four Cenozoic marine sedimentary strata in Japan. The occurrence of glendonite and concretions around dead organisms such as bivalves, ghost shrimp, or soft-bodied organisms forming ichnofossils, and the negative δ13C values of glendonite concretions around −20‰ to −10‰ showed that organic matter in dead organisms served as a carbon source for both ikaite crystals and the surrounding concretions. Highly concentrated phosphorus and its distribution patterns in glendonite concretions showed that changes of phosphate concentration in porewater play a crucial role in the sequential formation process from ikaite crystallization to syngenetically surrounding calcite concretion growth. The sequential processes of glendonite concretion formation progressed rapidly owing to the supply of bicarbonate during the decomposition of organisms in marine sediments. Our work provides a phosphate concentration-controlled growth model of glendonite concretion involving organic decomposition that can be used to evaluate paleoporewater chemical conditions during early diagenesis.

DOI： 10.1016/j.sedgeo.2021.106075

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人日本地球化学会  

To understand seawater properties, such as water mass structure and mixing, geochemical analyses are useful. However, geochemical datasets for seawater that fully cover coastal areas of Hokkaido, North Japan are lacking. Here we report comprehensive geochemical analyses of seawater (salinity, δ18O, δD, and Δ14C) collected in August–September 2021 from coastal areas of Hokkaido as well as the west coast of Tohoku (Northeast Japan). These datasets are expected to improve our understanding of seawater properties around Hokkaido, thereby contributing to oceanography, climatology, biogeochemical cycles, and fishery science.

DOI： 10.2343/geochemj.GJ22021

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>この40年間のAMS(Accelerator Mass Spectrometry) 14C分析の飛躍的な発展は、加速器質量分析装置の開発だけでなく、試料処理法の開発・自動化、さらに、14C較正曲線(最新版はIntCal20)の古い年代域までの充実、高精度化など、さまざまな分野が上手く兼ね合わって進化したことによるものである。現在、AMS 14C研究は、年代測定だけでなく、地球科学、宇宙科学、環境動態解析、最近では生命科学や創薬科学などの広い研究分野で活用されている。超小型AMS装置での多核種測定の開発も進められ10Be、26Al、その他の重元素の測定も可能になっている。さまざまな分野の研究者が協力することにより、今後もさらにAMS研究が発展していくことが期待される。本発表においては、これらの14C-AMSの開発の歴史をたどり、将来展望を行う。</p>

DOI： 10.14862/geochemproc.68.0_206

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>骨の無機成分 (バイオアパタイト) は埋没中に土壌からの汚染を受けやすく、分析に使えないと考えられてきたが、高温 (＞600℃)で加熱された骨はアパタイトの結晶度が高まることにより、汚染を受けにくくなり、元の情報を保持し得ることがわかってきた。滋賀県多賀町の敏満寺遺跡石仏谷墓跡(A～Gの各調査区に複数の墓が存在)からは高温で焼かれた火葬骨が多数出土し、古文書などから12～15世紀の敏満寺に縁のある各階層の僧が埋葬されていると考えられている。本研究では、A区・D区・F区・G区から出土した火葬骨についてSr同位体比・微量元素濃度・放射性炭素年代測定を行い、その年代と食性について考察した。</p>

DOI： 10.14862/geochemproc.68.0_153

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p> 大気エアロゾルは、大気中に浮遊している微小な液体や固体粒子のことであり、その主成分は炭素成分である。エアロゾル中の炭素成分については、化石燃料起源炭素(FC)と非化石燃料起源炭素(non-FC)に分類する方法がある。大気エアロゾル中の炭素成分の¹⁴C濃度を測定することで炭素成分における FC(0 pMC)とnon-FC(100 pMC)の比を導出することができ、都市大気によるnon-FCの発生源の解析や季節毎の寄与の差異の推定が試みられている。 本研究では、特に冬季の大気汚染の問題が深刻なイラン国内で、イラクの国境に近いクルディスタン州の都市で2019年10月～2020年6月に採取した大気エアロゾル試料について、そのバルク試料の¹⁴C濃度、δ¹³Cを測定した。試料採取時の気象データ(風向、風速など)も考慮して、大気エアロゾル中の炭素成分の発生源、季節変動について考察する予定である。</p>

DOI： 10.14862/geochemproc.68.0_28

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>イラン北西部にはジュラ系～白亜系の石灰岩が広く分布するとともに、第三紀〜第四紀に形成されたトラバーチン(石灰岩質沈殿岩)が広く産出する。トラバーチンは、地下水が湧出する時、溶け込んでいた二酸化炭素が脱ガスし、溶存していたカルシウムが炭酸カルシウムを生成して沈殿することで形成される。この沈殿物は、湧水の化学組成、沈殿生成時の温度などを記録していることが期待される。この地域のトラバーチンについては、Zarasvandi et al. (2017)やMohammadi et al. (2019)などの先行研究があるが、トラバーチンの化学分析、炭素・酸素同位体分析が中心であり、古環境解析への利用を視野に入れた年代測定や、湧水とトラバーチンの両試料の分析結果の直接対比はほとんど行われていない。本研究では、放射性炭素14Cを利用して、イラン北西部に分布するトラバーチンの形成年代の推定を試みた。</p>

DOI： 10.14862/geochemproc.68.0_66

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>イラン北西部の地域にはジュラ系～白亜系の石灰岩が広く分布するとともに、第三紀〜第四紀に形成されたトラバーチン(石灰岩質沈殿岩)も広く産出する。この地域は第三紀～第四紀の火山活動が活発であり、金属・非金属の鉱床も多く存在する。この地域のトラバーチン湧水(地下水)にはヒ素などの重金属元素を高濃度に含むものがある。生活環境や健康の面からの水質調査が行われているが、この地域のトラバーチン湧水のヒ素を含む様々な溶存元素についての詳細な地球化学的検討はなされていない。本研究では、イラン北西部地域のトラバーチン湧水の溶存元素の起源解析を主要・微量元素の定量分析と同位体分析を利用して行った。その結果、湧水およびその溶存元素は石灰岩から溶解した成分に火山由来の成分が付加して形成されていることが推察された。</p>

DOI： 10.14862/geochemproc.68.0_125

CiNii Research

担当区分：筆頭著者   記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p> 考古遺跡から出土する骨遺物は、昔のさまざまな情報を直接我々に与えてくれる。骨コラーゲンは、放射性炭素(¹⁴C)年代測定や炭素・窒素同位体比を用いた生前の食性解析に有効である。しかし、骨コラーゲンにおいても、土壌腐植物質や微生物などの外来有機物によって汚染している場合があり、信頼性のある年代測定・同位体分析を行うには、骨コラーゲンからさらに汚染物質を除去する必要がある。本発表においては、いくつかの除去方法を用いて骨有機質の高精度¹⁴C年代を実施した例を紹介する。 さらに近年、火葬骨に対し、骨無機質のバイオアパタイトを用いて¹⁴C年代測定、安定Sr同位体比(δ⁸⁸Sr)、Sr/Ca、Ba/Caなどによる生前の食性解析などが行われつつある。本発表では、いくつかの火葬骨の分析結果についても紹介したい。</p>

DOI： 10.14862/geochemproc.67.0_193

CiNii Research

担当区分：最終著者   記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>天然水の溶存無機炭素(DIC)の放射性炭素(¹⁴C)濃度は、水の滞留時間、大気と海洋の炭素交換、海洋の水循環、炭素供給源などを特定するのに有用である。水試料のDICを抽出する方法として、近年、ヘッドスペース法が広まりつつある。ヘッドスペース法はDICのδ¹³C分析に有効であるが、より多くの炭素量(1 mg程度)を必要とする¹⁴C分析には不適である。また、キャリアガスが必要で、専用のガラス真空ラインを作る必要があるという欠点がある。そこで、本研究においては、ヘッドスペース法を改良し、キャリアガスを用いず、既存のガラス真空ラインを用いて¹⁴C分析が可能な抽出システムを開発した。本システムは、容積の異なる容器を用いることで、様々なDIC濃度の水の炭素抽出が可能である。本発表では、いくつかの条件で新手法の炭素収率、¹⁴C値の精度・再現性をチェックした結果を報告する。</p>

DOI： 10.14862/geochemproc.67.0_157

CiNii Research

担当区分：最終著者   記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>骨の無機成分 (バイオアパタイト) は埋没中に土壌からの汚染を受けやすく、分析に使えないと考えられてきたが、高温 (＞600℃)で加熱された骨はアパタイトの結晶度が高まることにより、汚染を受けにくくなり、元の情報を保持し得ることがわかってきた。滋賀県多賀町の敏満寺遺跡石仏谷墓跡(A～Gの各調査区に複数の墓が存在)からは高温で焼かれた火葬骨が多数出土し、古文書などから12～15世紀の敏満寺の僧侶や周辺住民が埋葬されていると考えられている。本研究では、A区・F区・G区から出土した火葬骨と、石仏谷墓跡周辺の地域を流れる河川から採取した河川堆積物及び河川水、石仏谷墓跡から採取した土壌のSr同位体分析から、生前の食性と居住地について考察した。さらに火葬骨の微量元素濃度結果に対する考察も行う予定である。</p>

DOI： 10.14862/geochemproc.67.0_198

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>イラン北西部の地域にはジュラ系～白亜系の石灰岩が広く分布するとともに、第三紀〜第四紀に形成されたトラバーチン(石灰岩質沈殿岩)も広く産出する。この地域は第三紀～第四紀の火山活動が活発であり、金属・非金属の鉱床も多く存在する。この地域のトラバーチン湧水(地下水)にはヒ素などの重金属元素を高濃度に含むものがある。生活環境や健康の面からの水質調査が行われているが、この地域のトラバーチン湧水のヒ素を含む様々な溶存元素についての詳細な地球化学的検討はなされていない。本研究では、イラン北西部地域のトラバーチン湧水の溶存元素の起源解析を主要・微量元素の定量分析と同位体分析を利用して行った。その結果、湧水中のヒ素濃度は、鉄や硫酸濃度との相関関係が見られ、特に火成活動が活発な地域においてヒ素濃度が高いことが明らかとなった。</p>

DOI： 10.14862/geochemproc.67.0_126

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p> 堆積岩中に普遍的に見られる炭酸カルシウムのコンクリーションは，内部に化石を含むものだけでなく，化石を含まないものもある．化石を含むものであればその地層の年代決定に活用できるが，化石を含まない場合，年代決定は困難である．本研究では，石灰岩層などの年代決定に広く用いられているSr同位体層序を，炭酸カルシウム(CaCO3)を主成分とするコンクリーションに適用し，その堆積年代の決定を試みた．試料は，富山県八尾地域の中新統黒瀬谷層に産出するツノガイ化石を含むコンクリーションと化石を含まないコンクリーションを用いた．コンクリーションのカルサイト部分とツノガイの貝殻部分(アラゴナイト)に含まれるSrの同位体比を測定し，海水Sr同位体変動曲線との対比からそれぞれのSr同位体層序年代を求めた．</p>

DOI： 10.14862/geochemproc.67.0_166

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>Travertine is calcium carbonate precipitated from groundwater and spring water, and is widely distributed in northwest Iran. It is one of the suitable samples which can reconstruct paleoenvironment on land with a high resolution.In this study, I first determine the formation age of the travertine and then reveal its source by a series of data of 14C, δ13C, δ18O, 87Sr/86Sr and major- and trace-elemental compositions.</p>

DOI： 10.14862/geochemproc.67.0_200

CiNii Research

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

The preservation of unpoisoned water samples was investigated by radiocarbon analysis with five kinds of natural waters. Although refrigerated and shielded from light, the unpoisoned samples underwent carbon isotopic changes, even after short periods of storage (e.g., 5 days). Examinations of the isotopic changes during long-term preservation (580 or 860 days) revealed 14C increases to be approximate 10 pMC and δ13C decreases to be −5.4‰. Performance tests on the sample bottles suggested that PAN (polyacrylonitrile) and glass were suitable materials for long-term preservation.

DOI： 10.1016/j.nimb.2018.11.029

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記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>We have elucidated retention of primary Sr isotopic ratios in source rocks to sediments and sedimentary rocks during repeated sedimentation recycling. Twenty-three fine stream sediments (<180 μm) in Awajishima Island were used for the study. The ⁸⁷Rb/⁸⁶Sr and ⁸⁷Sr/⁸⁶Sr of stream sediments originated from Cretaceous Ryoke granitic rocks and Cretaceous sedimentary rocks (Izumi Group) were similar to those of the respective source rocks. Incidentally, the ⁸⁷Rb/⁸⁶Sr-⁸⁷Sr/⁸⁶Sr of stream sediments in Awajishima Island suggests that Cretaceous felsic igneous rocks are the dominant source of clastics in Izumi Group. Stream sediments derived from Neogene and Quaternary sediments, which are originated from granitic rocks and Izumi Group, had comparable isotopic ratios to those of the respective primitive source rocks. Accordingly, ⁸⁷Rb/⁸⁶Sr and ⁸⁷Sr/⁸⁶Sr can be retained during the repeated recycling process of sediments and sedimentary rocks. Stream sediment is presumed to consist of clastics supplied from respective lithologies according to their exposed areas. However, ⁸⁷Sr/⁸⁶Sr of stream sediment is not comparable to the values calculated from exposed areas of lithologies and isotopic data of parent rocks. The result suggests that amount of sedimentation denudation and production differs among different lithologies and is not simply proportional to their exposed areas.</p>

DOI： 10.14934/chikyukagaku.53.59

CiNii Research

記述言語：日本語   出版者・発行元：Scientific Reports  

The publication date was omitted from the original PDF version of this Article. This error has now been corrected in the PDF version; the HTML version was correct from the time of publication.

DOI： 10.1038/s41598-019-40680-w

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Isolated spherical carbonate concretions are frequently observed in finer grained marine sediments of widely varying geological age. Recent studies on various kinds of spherical carbonate (CaCO3) concretions revealed that they formed very rapidly under tightly constrained conditions. However, the formation ages of the isolated spherical carbonate concretions have never been determined. Here we use 87Sr/86Sr ratios to determine the ages of these spherical concretions. The studied concretions formed in the Yatsuo Group of Miocene age in central Japan. Some formed post-mortem around tusk-shells (Fissidentalium spp.), while other concretions have no shell fossils inside. The deformation of sedimentary layers around the concretions, combined with geochemical analyses, reveal that Sr was incorporated into the CaCO3 concretions during their rapid formation. Strontium isotopic stratigraphy using 87Sr/86Sr ratios of all concretions indicates an age of 17.02 ± 0.27 Ma, with higher accuracy than the ages estimated using micro-fossils from the Yatsuo Group. The results imply that the 87Sr/86Sr ratio of isolated spherical carbonate concretions can be applied generally to determine the numerical ages of marine sediments, when concretions formed soon after sedimentation. The 87Sr/86Sr age determinations have high accuracy, even in cases without any fossils evidence.

DOI： 10.1038/s41598-019-38593-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

<p></p>

DOI： 10.14863/geosocabst.2019.0_566

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>近年、多年地下氷(アイスウェッジ)の安定同位体比から完新世の冬季気温が復元可能であることが報告され、代替古環境プロキシとしての永久凍土の可能性が注目されている。地下氷に保存された過去の気候変動や水文環境変化を読み解くうえで、まず、地下氷の形成年代を正確に決定することが重要である。そこで本研究では、地下氷試料に対し、これまで一般的に年代測定に用いられてきたPOCに加えて、DOC、DICの¹⁴C年代を測定し、どの炭素成分が最も正確な形成年代を示すかを調べた。用いた試料は、シベリアのSyrdakh、およびChurapchaの露頭から採取された地下氷である。その結果、地下氷の ¹⁴C年代は、POC＞植物片・粗粒DOC・(細粒DOC)＞DIC・(細粒DOC)の順に若くなる傾向が見られた。発表においては、地下氷の各炭素成分が何の年代を示しているのかを考察し、地下氷の形成年代を正確に決定するには、どの炭素成分を用いるのが最も有効であるのかを議論する。</p>

DOI： 10.14862/geochemproc.66.0_87

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>Travertine is calcium carbonate precipitated from spring water, groundwater and so on and is widely distributed in northwest Iran. In this study, we first determine the formation age and then reveal the origin and formation process of the Iranian travertine by a multi-proxy geochemical analysis to evaluate a potential of the travertine deposits for paleoclimatic and paleoenvironmental implications. </p>

DOI： 10.14862/geochemproc.66.0_99

CiNii Research

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Geology  

Quantitative electron probe microanalysis (EPMA) of trace elements using wavelength dispersive spectrometers (WDS) requires high probe current and/or accelerating voltage and long X-ray sampling times to measure weak X-ray signals from target materials. The X-ray count rate of a standard material is extremely high when measured under the same conditions. Consequently, the accuracy of the dead time correction becomes a significant issue for quantification. Accurate dead time correction requires an exact knowledge of the X-ray counting system, including the behavior of the proportional counter and electronic circuits. Each spectrometer has a specific dead time that depends on factors such as electronic circuit design, counter bias, and X-ray energies. The dead time also changes with aging degradation. A pseudo-fixed dead time correction circuit with non-extendable approximation is described that prevents systematic errors in quantitative EPMA caused by inappropriate dead time corrections. The circuit, which is added to the output of the single channel analyzer, includes one extendable and two non-extendable dead time generators with dead times of 0.68 μs, 1.08 μs, and 1.92 μs, respectively. The behavior of the whole system can be treated as non-extendable for most applications, with a dead time of approximately 2.01 μs. The pseudo-fixed dead time circuit suppresses systematic error of the dead time correction to 0.6% or less when the original dead time is between 0.8–2.0 μs and the true X-ray count rate is < 200 kcps. This makes it possible to perform accurate dead time corrections without periodic measurement of the dead time throughout the life of the proportional counter by implementing a high-precision crystal oscillator in the system.

DOI： 10.1016/j.chemgeo.2017.12.030

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Isolated spherical carbonate concretions observed in marine sediments are fascinating natural objet trouve because of their rounded shapes and distinct sharp boundaries. They occur in varied matrices and often contain well preserved fossils. The formation process of such concretions has been explained by diffusion and rapid syn-depositional reactions with organic solutes and other pore water constituents. However, the rates, conditions and formation process of syngenetic spherical concretions are still not fully clear. Based on the examination of different kinds of spherical concretions from several locations in Japan, a diffusion based growth diagram was applied to define the generalized growth conditions of spherical concretions formed around decaying organic matter. All analytical data imply that the spherical concretions formed very rapidly, at least three to four orders of magnitude faster than previously estimated timescales. The values indicate that spherical concretions are preferentially grown within clay- to silt-grade marine sediments deposited in relatively deep (a few tens of metres) environments dominated by diffusive solute transport, very early in diagenesis.

DOI： 10.1038/s41598-018-24205-5

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Geophysical Research: Oceans  

The excess radiocarbon produced by nuclear bomb testing in the atmosphere in the 1950s–1960s (bomb-14C) is used as a tracer in the surface ocean, extending our understanding of geophysics and biogeochemical cycles. However, there is no bomb-14C record for the high-latitude western North Pacific Ocean because of the paucity of long-lived marine calcifying organisms equivalent to reef-building corals. The shells of Stimpson's hard clam, Mercenaria stimpsoni, potentially provide such a record because the clam's lifespan is very long (>100 years). We analyzed 14C in six live-caught M. stimpsoni shells from the western North Pacific (39.4°N, 142°E) and report, for the first time, the bomb-14C record with robust calendar ages based on annual growth increments. The value was constant in 1934–1952 (Δ14C = −66‰), with a sudden increase in 1959, a peak in 1974 (107‰), which was 60‰ lower than that of the Kuroshio Current, a gradual decline after 1974, and a current value of 16–18‰, which is ∼10‰ higher than the atmospheric value. The bomb-14C values are between the Kuroshio Current (the northwestern subtropical gyre) and Oyashio Current (the Western Subarctic Gyre) values, suggesting that the Tsugaru Current, downstream from the Kuroshio Current, mixes with the Oyashio Current after passing through Tsugaru Strait.

DOI： 10.1002/2017JC013678

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記述言語：日本語   出版者・発行元：名古屋大学宇宙地球環境研究所  

Burned bones may not provide accurate 14C dating because of no remain of collagen, an organic fraction in bone, suffered from heating. It is a very crucial assignment to enable burned bone to be 14C-dated. The purpose of this study is to test the reliability of 14C dating of carbonate hydroxyapatite (CHa), an inorganic fraction in bone, by using some burned bones from archaeological sites. The samples tested are five burned bones with gray to black colors of known-age collected from the Göytepe and Damjili Cave archeological sites in Azerbaijan. The XRD patterns of the bones showed that they had not suffered from the heat of &gt;600ºC, and that they have low crystallinity of apatite. The 14C dates of the Göytepe and Damjili Cave bones were younger than the dates obtained by charred materials excavated from the same layer for 400 years and 1000–1700 years, respectively. The results indicate that the bones burned at the low temperature (&lt;600ºC) have been heavily contaminated through diagenetic alteration during burial because of low crystallinity of apatite, and that the contaminants can not be removed from bone CHa by chemical treatment used in this study. In conclusion, secondary carbonate can be removed from even bones burned at low temperature (&lt;600ºC) by acetic acid treatment, while exogenous carbon included into the inner site of CHa can not be removed. The degree of contamination from foreign carbon in bone samples varies with burial condition. Therefore, it is important to check the apatite crystallinity of bone and burial environment of bones to perform reliable 14C dating using bone CHa.遺跡に埋没している被熱骨に対し，炭酸ヒドロキシアパタイトを用いて信頼性のある14C年代測定が可能であるかを検証した．用いた試料は，アゼルバイジャンのギョイテペ遺跡とダムジリ洞窟遺跡から出土した被熱動物骨7点である．これらの骨試料の炭酸ヒドロキシアパタイトの14C年代は，同層から得られた炭化植物片の年代よりも，ギョイテペ遺跡においては400年，ダムジリ洞窟遺跡においては1000-1700年程度若くなった.XRDパターン結果から，二次的に付着した炭酸塩は，試料の酢酸処理によって除去されていると考えられ，若くなった原因は，炭酸ヒドロキシアパタイト結晶内に入り込んだ汚染炭素によるものと考えられる．ギョイテペ遺跡とダムジリ洞窟遺跡遺跡による年代差は，ギョイテペ遺跡の周辺は火成岩が，ダムジリ洞窟の周辺は石灰岩が分布していて土壌環境が異なっていたためと考えられる．今後さらに，埋没環境，被熱温度が異なる骨試料に対し，炭酸ヒドロキシアパタイトを用いて信頼性のある14C年代を得るための検討を行なっていく必要がある．

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>1950年から1960年代にかけて世界中で行われた大気圏核実験に伴い、地表の放射性炭素が急増した。海水の核実験起源¹⁴C記録は海水炭素循環の理解を深める上で役立つが、比較的長寿の生物の硬組織が必要であることから、これまでに得られた記録は造礁サンゴが分布する熱帯〜亜熱帯域に偏っている。我々は、北日本の浅海底から見つかった長寿二枚貝ビノスガイ(<i>Mercenaria stimpsoni</i>)の殻を用いて、北西太平洋高緯度域としては初となる記録を作成した。復元されたBomb-¹⁴C記録から、三陸海岸の浅海域において、津軽暖流(対馬海流を起源とする)の影響が強く見られることがわかった。さらに、得られたBomb-¹⁴C記録を船越湾(岩手県大槌)の海底から得られたビノスガイの死殻の高精度の年代決定ツールとして用いることで、2011年3月11日の大津波がビノスガイの大量死を招いていたことがわかった。</p>

DOI： 10.14862/geochemproc.65.0_228

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>琵琶湖の主要河川である安曇川と野洲川を対象とし、それぞれの河川の上流・中流・下流域の河床堆積物を用いて、堆積物中の10Beの存在形態、粒径の違いによる10Be濃度の違いを調べた。その結果、河床堆積物の10Beの大部分は堆積物表面の吸着成分に存在していること、細粒の堆積物は単位質量当たりの表面積が大きいため、10Beが多く吸着していること、河川による10Beの違いは河川水のpHなど河川環境に影響されることが明らかになった。本研究は、堆積物の河川から湖への10Beの輸送プロセスを理解するためには粒子に吸着した10Beと河川水に溶存した10Beの両方を考える必要があることを示している。</p>

DOI： 10.14862/geochemproc.65.0_231

CiNii Research

担当区分：筆頭著者   記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>前橋台地の一帯に広く分布する前橋泥流堆積層に含まれる木片の14C年代を酸-アルカリ-酸化(ABOx)処理+段階加熱(SC)法を用いて高確度に求めることにより、前橋泥流が流下・堆積した年代の再検討を行った。木片の14C年代測定の結果、6点は21,600 BPから22,570 BPの14C年代を、1点は33,600 BPという古い年代を示した。前橋泥流に含まれる木片のほとんどが径10 cm程度かそれ以下であって、太い樹幹は全く見られないことから古木効果は考えられず、1000年の年代幅は、複数回の泥流流下が生じた可能性を示唆している。また、今回得られた33,600 BP、21,600—22,570 BPは、それぞれ上部ローム層下位の暗色帯に包有される後期旧石器時代初頭の岩宿I文化、および上層の後期旧石器時代後半の岩宿II文化に対応している可能性がある。今後さらに、14C年代の測定数を増やし、前橋泥流堆積層の年代を明らかにする必要がある。</p>

DOI： 10.14862/geochemproc.65.0_291

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

<p>球状炭酸塩コンクリーションは，世界各地の様々な地質時代の海成層から普遍的に産するが，その形成過程はいまだ完全には理解されていない．本研究では，愛知県知多半島の先端部に分布する中新統師崎層群下部豊浜累層中にみられる長径約1.5mの巨大ドロマイト質コンクリーションについて，その形成過程を明らかにすることを目的に，堆積学的および地球化学的な種々の観察・分析を行った．その結果，埋没深度数百mに達するまでのごく初期続成過程においてメートルサイズの巨大なコンクリーションが形成することが示された．その形成時間は数十年と見積もられ，これまで考えられていた巨大炭酸塩コンクリーションの形成速度よりもはるかに速いものである．</p>

DOI： 10.5575/geosoc.2017.0039

CiNii Research

J-GLOBAL

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Geochemistry  

We are preparing a nationwide distribution map of strontium isotope ratio (87Sr/86Sr) in Japan, using stream sediment to obtain basic 87Sr/86Sr data for the provenance analysis of food production and archaeological substances. To clarify the effect of particle size on 87Sr/86Sr in stream sediments, we analyzed stream sediment from the Shigenobu River system in Matsuyama, Ehime Prefecture, Japan, where a variety of silicate-dominated lithologies, that is, several bedrocks of andesitic, granitic, and siliciclastic sedimentary rocks, are distributed. This paper reports elemental concentrations and 87Sr/86Sr in stream sediments for six particle-size fractions (1000–500, 500–300, 300–180, 180–125, 125–75, and <75 μm). The results from stream sediments were compared with results from bedrock units and stream water over the catchment. The elemental concentrations in stream sediment tended to increase with decreasing particle size in all lithologies; however, Sr concentrations varied less than other elements across particle sizes. For most of the samples, 87Sr/86Sr varied by less than 0.001 among the six particle-size fractions, which was less than the variation among the different lithologies. Therefore, 87Sr/86Sr in the <180 μm particle-size fraction, which is normally used in Japanese nationwide geochemical mapping, should be a reliable proxy for bedrock 87Sr/86Sr. The 87Sr/86Sr values in water samples from the Shigenobu River system were lower and less variable than 87Sr/86Sr in the stream sediments, and they did not faithfully correspond to the watershed geology. The inconsistency may reflect selective dissolution of Sr from plagioclase. Interestingly, 87Sr/86Sr values of the exchangeable fraction of stream sediment in the <180 μm fraction were strongly correlated with 87Sr/86Sr of stream water samples. Because 87Sr/86Sr in plant and animal bodies reflects that of their water sources, the exchangeable fraction of stream sediment may be a useful proxy for geochemical provenance in Japan instead of stream water.

DOI： 10.1016/j.apgeochem.2017.09.004

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Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人日本地球化学会  

The strontium isotope ratio (87Sr/86Sr) is often used to identify the origin of agricultural products and the movement of ancient people, and a nationwide 87Sr/86Sr distribution map would greatly assist such studies. The Geological Survey of Japan (GSJ), AIST has already created nationwide element distribution maps using the <180 μm fraction of stream sediments, but this grain size fraction may not necessarily be suitable for mapping the 87Sr/86Sr isotopic ratio. Therefore, this study investigated the effect of grain size on elemental concentrations and 87Sr/86Sr ratios in stream sediments and compared their values with those of the source rocks. The stream sediments studied were collected from the granitic drainage basin of the Yahagi and Yada rivers in Aichi Prefecture, central Japan. The elemental concentrations and 87Sr/86Sr ratios of five fractions in the size range 1000-75 μm from the stream sediments of the Yahagi River tributaries varied with the grain size, and the variations corresponded to the heterogeneity of the mineral compositions in each fraction. The difference in the elemental concentrations and 87Sr/86Sr ratios among the sampling points was smallest in the 300-75 μm fractions, which showed 87Sr/86Sr and 87Rb/86Sr values that were closest to those of the source rocks. The coarser (>300 μm) and the fine (<75 μm) fractions of the stream sediments showed systematically higher 87Rb/86Sr and lower 87Sr/86Sr ratios than the Rb-Sr mineral isochron for the source rock, and the result suggests that 1) these fractions are enriched in K- and Rb-rich minerals such as K-feldspar, biotite, and hornblende; and 2) Sr is lost relative to Rb because of weathering processes. Furthermore, temporal variations in 87Sr/86Sr of the <180 μm stream sediments collected at a fixed sampling site in the Yada River were 0.001, which is smaller than the variations associated with grain size seen in the 87Sr/86Sr values in the granitic study area. Consequently, we concluded that, in granite areas, the <180 μm fraction of the stream sediments can be used for 87Sr/86Sr mapping, implying that a nationwide 87Sr/86Sr map can be made using sediment samples with a grain size of less than 180 μm.

DOI： 10.2343/geochemj.2.0478

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Scopus

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：東北地理学会  

<p>Maibah beach is located between Higashihenna promontory and Miyato-zaki （promontory）, southeast of Miyako Island. Along the sandy beach, beachrock develops intertidal zone. A large boulder lying on the eastern part of the beach has been recognized as a fossil <i>Tridacna gigas</i>. We collected two samples from the boulder in order to determine the age of its outer layer, and noticed that the cross section was different from <i>Tridacna gigas</i>. The samples indicated obviously a characteristic of coralline structure. Then identification and radiocarbon dating of the samples were performed.</p><p>The results show that coral is <i>Porites</i> sp. and probably <i>in situ</i>, and that it was transported from lagoon and beached on the shore, judged from the field observation. The calibrated ages were 1626 cal AD and 1679 cal AD, respectively. It is considered that <i>Porites</i> had transported and beached on the shore by huge tsunamis or high waves of typhoon. Unfortunately there was no huge typhoon record, and then we tried to correlate calibrated age of <i>Porites</i> with historical tsunami and earthquake records. According to historical record, Miyako Islands were attacked by strong earthquake of AD 1667 which probably caused tsunami. An average calibrated age of <i>Porites</i> （1653±23 cal AD） coincides with AD 1667 earthquake tsunami with a margin of statistical error. However, age of removed soft outer layers of <i>Porites</i> strongly suggests that it was transported from its original habitat to the present location not only by AD 1667 earthquake tsunami but also by AD 1771 Meiwa Tsunami.</p>

DOI： 10.5190/tga.69.3_119

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>本研究では、考古遺物の火葬人骨から抽出した結晶性の異なる炭酸ヒドロキシアパタイトに対して、放射起源Sr同位体に加えて安定Sr同位体の分析を行うことで、埋没後の続成作用で生じたSr同位体組成の二次的変化を定量的に評価することを試みた。持聖院五輪塔下より出土した貞慶(AD1155−1213)のものと伝わる火葬骨および敏満寺石仏谷墓跡より出土した火葬骨は、ともに黒色を呈している骨片が白色を呈している骨片より高いδ88Sr値を示し、続成作用の影響を強く受けていることが示唆された。白色骨片はアパタイトの結晶性が高いが、黒色骨片はアパタイトの結晶性が低く有機物の残留が見られるこの違いが、変質耐性に大きく影響したと考えられ、続成作用時にSrの溶脱と同時に無視できない規模でSrの同位体交換が生じうることが示された。</p>

DOI： 10.14862/geochemproc.64.0_14

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>遺跡から出土する骨遺物から年代や食性の情報を得るためには、有機成分の骨コラーゲン中の放射性炭素(14C)年代測定や炭素・窒素・酸素安定同位体比測定を行うのが一般的である。しかしコラーゲンは加熱により容易に分解するため、火葬された骨の年代測定や食性解析には使えない。そこで、我々は、加熱後も骨に残存しうる無機成分の炭酸ヒドロキシアパタイト(Carbonate Hydroxyapatite: CHa)に着目し、その有用性を検討している。これまでの研究から、火葬骨に混入している二次的な炭酸塩等の汚染物質を適切な化学処理で除去することにより、CHaから正確な14C年代、さらに、Sr/CaやSr安定同位体比を用いて食性解析が可能であることが明らかになりつつある。 本講演においては、どのような火葬骨であれば、CHaによる信頼性のある14C年代や食性解析が可能であるかを明らかにするため、加熱温度の違いによる骨CHa中のアパタイトの結晶性の違い、汚染の受けやすさの違いについて調べた結果を報告する。</p>

DOI： 10.14862/geochemproc.64.0_202

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>クルディスタン大学はイラン北西部サナンダジュ市にある国立の総合大学である。数学の研究と教員養成から発展した大学では、沙漠環境や乾燥地バイオを含む農学部や天然資源学部など多様な研究と教育が進められている。基礎理学部に属する地球科学科の研究と教育は、同位体を用いた岩石学や炭酸塩地球化学を中心としている。演者らは、使用済み英文教科書のご寄贈をお願いした。その結果、全国各地から180冊を越える教科書をお送り頂いた。第１陣は平成29年3月末にイランに発送し、７月に第２陣を予定している。</p>

DOI： 10.14862/geochemproc.64.0_124

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

DOI： 10.14863/geosocabst.2017.0_443

CiNii Research

記述言語：日本語   出版者・発行元：Radiocarbon  

Charcoal is widely used for radiocarbon dating in archaeological and paleoenvironmental studies. Reliable14C dating requires appropriate chemical treatment to remove postdeposition contamination from the charcoal samples. This study assesses two pretreatments: acid-base-acid (ABA) and acid-base-oxidation with stepped combustion (ABOx-SC). In addition to14C, the effects of the treatments on the chemical structure and composition of charcoal were studied using Fourier transform infrared spectroscopy (FTIR) and C/H/O elemental analysis. Samples of pine wood charred in the laboratory at 270, 300, 400, 500, and 600°C, and environmental samples of charred pine wood from pyroclastic flow deposits in southern Kyushu, Japan, were tested. The laboratory-charred samples showed that NaOH treatment removed highly hydrophilic organic components derived from endogenous and exogenous organic materials in the samples and that oxidation treatment caused the oxidative degradation of molecules in samples starting from its edges. The ABA-treated environmental charcoal yielded younger14C dates than the ABOx-treated samples, probably owing to the effects of remaining organic contaminants bound to the edges of the aromatic molecular structures produced by the original pyrolysis. Meanwhile, it was found that ABA-SC treatment can reduce contaminants as effectively as ABOx-SC treatment. This implies that the stepped combustion (SC), not the chemical oxidation, is the key to reduce contaminant residue left after ABA and ABOx treatments. The results in this study indicate that the investigation of the structural and compositional changes of charcoal during its pretreatment is useful for assessment of the reliability of the14C ages.

DOI： 10.1017/RDC.2016.29

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

Chemical compositions and Sr isotopic ratio (⁸⁷Sr/⁸⁶Sr) of stream sediments collected from Akiyoshi-dai, where is underlain by a large-scale limestone bedrock, were measured to investigate the influence of limestone bedrocks on geochemical maps. The sediments were sieved with eight screen sizes, and their bulk and acetic acid soluble fractions were both analyzed. 50–100% of the total Ca was extracted by acid leaching from stream sediments in the catchment of Akiyoshi limestone, indicating that Ca exists mainly in carbonate materials. In contrast, only 5–10% and 15–45% of the total Sr were extracted from their coarse (>125 μm) and fine particles (<125 μm),respectively. Therefore, Sr exists dominantly in aluminosilicate minerals even in stream sediments originated from limestone bedrock. Because the acid extraction percentages of Ca and Sr increase exponentially below 125 μm of grain size, carbonate materials would be supplied by fine-grained particles from limestone bedrock. ⁸⁷Sr/⁸⁶Sr ratios in the acid soluble fractions were systematically lower than those of the bulk fractions and comparable to ⁸⁷Sr/⁸⁶Sr of Akiyoshi limestone. Although limestone bedrock apparently scarcely influence on Sr concentration and ⁸⁷Sr/⁸⁶Sr of stream sediments, ⁸⁷Sr/⁸⁶Sr of carbonate materials is successfully extracted from the bulk sediments using acetic acid-based extraction method.

DOI： 10.14934/chikyukagaku.50.11

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

<p>近年、石筍の14Cは、年代測定のツールとしてよりも、IntCal曲線(大気の14C)と比較することにより、過去の水循環を知るための有効なプロキシとして注目されている。実際にいくつかの石筍の報告例から、大きいDead炭素の寄与率(Dead Carbon Fraction: DCF)をもつ石筍は、成長期間中のDCFが一定ではなく、気候によって変化した可能性があると指摘されている。我々は、静岡県の竜ヶ岩洞内の石筍の14Cを調べた結果、温暖期にDCFが小さくなる傾向が見られた。この結果はNoronha et al. (2014)とは逆、同地点から採取された滴下水の2年間にわたる結果とは同じ傾向であった。本発表においては、この竜ヶ岩洞石筍のDCF変化について、δ18O値、Mg/Ca比、Cd/Ca比、87Sr/86Sr等の結果と比較しながら議論し、石筍のDCF変化が降水量のプロキシとなり得るかについて考察する。</p>

DOI： 10.14862/geochemproc.63.0_22

CiNii Research

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

Speleothem 14C has recently emerged as a potentially powerful proxy for hydrology changes in comparison with atmospheric 14C calibration curve, rather than as a direct dating tool, apart from a time marker using bomb peak of 14C. Some possible causes for the relationship between speleothem 14C content (or dead carbon fraction: DCF) and karst hydrology have been proposed, such as changes in temperature, precipitation, drip water flow dynamics, cave air ventilation, soil air pCO2. In this study, we investigated seasonal variation in 14C and δ13C of drip water in Ryugashi Cave, Shizuoka Prefecture, central Japan, to examine the causes of the 14C and δ13C variations in a speleothem. The results show that different 14C concentrations and δ13C values of drip water from the Ryugashi Cave, were exhibited at different sites of the Caves No. 1, No. 3, and No. 4, which have different temperature, air pCO2, and flow paths. Further, the 14C and δ13C of drip waters showed seasonal variations at all sites, which were lower in fall and winter, and higher in spring and summer, though the extent of the variations was different among the sites. The 14C in drip waters tended to be correlated with the drip rates: 14C tended to be higher in drip waters with higher drip rates, and also correlated with rainfall amount around the Ryugashi Cave, especially for the drip waters in Cave No. 3, which are considered to have simpler flow paths. The increase in rainfall amount could bring the increase in drip rate of drip water, and then the decrease in interaction between solution and karst, resulting in 14C increase (DCF decrease) in drip water. Accordingly, the reconstruction of precipitation could be performed using 14C variation in a speleothem formed by drip water with simple flow dynamics.

DOI： 10.1016/j.nimb.2015.05.020

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Carbonate concretions occur in sedimentary rocks of widely varying geological ages throughout the world. Many of these concretions are isolated spheres, centered on fossils. The formation of such concretions has been variously explained by diffusion of inorganic carbon and organic matter in buried marine sediments. However, details of the syn-depositional chemical processes by which the isolated spherical shape developed and the associated carbon sources are little known. Here we present evidence that spherical carbonate concretions (diameters φ : 14 ∼ 37 mm) around tusk-shells (Fissidentalium spp.) were formed within weeks or months following death of the organism by the seepage of fatty acid from decaying soft body tissues. Characteristic concentrations of carbonate around the mouth of a tusk-shell reveal very rapid formation during the decay of organic matter from the tusk-shell. Available observations and geochemical evidence have enabled us to construct a 'Diffusion-growth rate cross-plot' that can be used to estimate the growth rate of all kinds of isolated spherical carbonate concretions identified in marine formations. Results shown here suggest that isolated spherical concretions that are not associated with fossils might also be formed from carbon sourced in the decaying soft body tissues of non-skeletal organisms with otherwise low preservation potential.

DOI： 10.1038/srep14123

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   出版者・発行元：一般社団法人日本鉱物科学会  

本研究では，西南日本内帯・山陰帯の深成岩マグマ史を調べるために，東部因美迸入岩類の花崗岩類（人形峠花崗岩，鳥取花崗岩，三軒屋花崗閃緑岩）の全岩組成分析を行ない，更にSrとNdの同位体組成分析を行なった．全岩の化学的特徴は，それらをIタイプ花崗岩に分類した．人形峠花崗岩6試料のRb-Srアイソクロン年代は66.1 +/- 5.0 Ma (1 sigma) であった．NdIとSrIのイプシロン図上では，人形峠花崗岩と鳥取花崗岩が別のマグマ起源として示された．

DOI： 10.14824/jakoka.2014.0_181

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

水試料の放射性炭素濃度の経時変化と保管容器の材質についての検討を行った。ガラス、PAN樹脂、PP樹脂の容器のそれぞれに試薬から調製した試料を分取して、放射性炭素濃度の経時変化を測定した。ガラス容器は、容量が130mL程度で、グリスを塗布した摺合せ栓で密閉しており（ビニールテープで固定）、容器内の上部に数mL程度の大気が残っている。PAN樹脂とPP樹脂の容器は、容量が300mL程度で、内部に大気が残らないようにしてPP製のスクリューキャップで密閉して保管した。　放射性炭素濃度の経時変化は、glass容器とPAN樹脂容器で小さく、PP樹脂容器で大きい結果となった。一方で、PP樹脂容器の炭素安定同位体比は大きな変化をしていない。混入してきた炭素成分との値の差が放射性炭素とは異なるためと思われる。PP樹脂容器は水試料の採取では一般的に用いられるが、炭素同位体分析用の試料容器には不向きであることが示された。

DOI： 10.14862/geochemproc.61.0_120

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

キツネは50年ほど前まで里山の至る所に生息していた最もポピュラーな野生動物であり、愛知県豊田市の市街地から北東に約17 km離れた山間集落である小手沢にも、1960年代初めまでは多くのキツネが生息していた。しかし、キツネは1960年代後半から次第にいなくなり、現在では全く目撃されなくなっている。そこで、本研究では、小手沢集落の旧地蔵堂の解体（2010年1月17日）中に床下から見つかったキツネ遺骸の歯および骨の14C濃度から、それぞれ誕生および死亡年代を求め、キツネが里山から消えた時期を明らかにすることを目的とした。このキツネの遺骸の脇には1971－1983年版のチキンラーメンの袋が見つかっていることから、キツネが消えた時期を解明する鍵になると推察された。本発表においては、14C年代測定の他、C・N・Srの安定同位体比の測定も行ない、キツネの食性を推定することにより、キツネが里山から消えた原因も考察する。

DOI： 10.14862/geochemproc.61.0_245

CiNii Research

担当区分：筆頭著者   記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

水のDICの14C分析のための化学処理法としては、沈殿法、バブリング法、ヘッドスペース法などが用いられている。海水試料については、バブリング法を用いたWOCE基準と呼ばれる国際標準の処理法が取り決められているが、海水以外の水試料の14C分析法についての取り決めはない。そこで我々は、水試料の化学処理法の違いによる14C相互比較を行うプログラム（RICE-W: Radiocarbon Intercomparison on Chemical Experiments, Water series）を立ち上げ、DIC濃度・塩濃度の異なる水試料（海水、温泉水、地下水等）を6研究機関に配布し、14C相互比較を開始した。本発表では、これまでに得られた結果のうち、化学処理法による違い、水銀添加の効果、14C濃度の経時変化について報告する。

DOI： 10.14862/geochemproc.61.0_121

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

花崗岩起源の河川堆積物の粒径別元素濃度及び<SUP>87</SUP>Sr/<SUP>86</SUP>Srを測定し、粒径分画ごとの河川堆積物の特徴について検討した。多くの元素で細粒分画ほど濃度が高くなる傾向が見られ、また<SUP>87</SUP>Sr/<SUP>86</SUP>Srについても、全体としては母岩の値にほぼ等しい値が得られたが、粒径分画ごとに多少の変動を示した。これは各粒径分画に含まれる鉱物比が異なるためであり、鉱物の物理的風化に対する耐性の違いや比重の違いと考えられる。また、CIAの値も各粒径分画で異なり、化学的風化の程度も異なることが示唆された。本研究域の花崗岩起源河川堆積物においては、300－180 ?m分画の河川堆積物の元素濃度・<SUP>87</SUP>Sr/<SUP>86</SUP>Srが最も母岩に近い値を示し，地点間のばらつきを最小に抑えられることが明らかになった。

DOI： 10.14862/geochemproc.61.0_347

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

古気候・古環境研究とは、広い時空間スケールにわたって宇宙－地球間や海洋－大気－陸域の各系間における多様なリンクについて知り、そこから地球表層環境の本質をえぐり出す研究分野である。多くのオープンクエスチョンの中でも「気候変動のドライビングフォース」・「物質循環」・「進化」に関する内容は関心が高い。このような問題の解決に地球化学が貢献すべき点は多く、新しい代替指標や分析法の開発、データの時空間スケールの高度化といったアプローチが必要不可欠である。研究推進には、労力と予算に加え、堆積物コア・アイスコア・サンゴなど古気候情報をもつ試料採取・分配をはじめとし、分野全体を網羅かつ統括した体制づくりが重要となる。大きな拠点を作り、微量安定同位体測定装置や目的に応じた各種質量分析計など先端的な大型装置を導入するといった大型予算を伴うやり方、古環境・古気候研究を進める既存のラボを有機的につなげたバーチャルラボラトリーの構築とネットワーク強化といった低予算型のやり方まで、複数のプランを練っておく必要がある。

DOI： 10.14862/geochemproc.61.0_134

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

炭化物は、長期間の埋没環境下でも化学的に安定であるため、遺跡の<SUP>14</SUP>C年代測定の試料として有用である。化学処理では、ABA処理が一般に用いられている。しかし近年、ABOX処理が注目されている。両者の方法によって<SUP>14</SUP>C年代値が異なる例が報告されているが、その要因について、処理後の試料の化学構造の違いという視点からの議論はされていない。本発表では、ABA処理とABOX処理後の炭化物の化学構造の違いと、それによる<SUP>14</SUP>C年代値への影響について述べる。各処理後の試料に対し、赤外吸収スペクトルの観測、C・H・Oの元素含有率の測定、および<SUP>14</SUP>C年代測定を行った。以上の分析結果より、ABOX試料では分子量が大きな多環芳香族を得ることができるため、外来炭素による汚染のない、より信頼性のある<SUP>14</SUP>C年代を示す可能性があると考えられる。

DOI： 10.14862/geochemproc.61.0_244

CiNii Research

記述言語：英語   出版者・発行元：一般社団法人日本地球化学会  

Geochemical mapping of 87Sr/86Sr ratios in Shikoku Island and the Kii Peninsula of Southwest Japan was performed using 233 samples of stream sediments (<180 μm). The spatial distribution of 87Sr/86Sr ratios successively increases from northern to southern geological units, with a gap at the Median Tectonic Line (MTL). In the Inner Zone divided by the MTL, a zone with Cretaceous granitoid rocks of the Ryoke Belt and sedimentary rocks of the Izumi Group, the 87Sr/86Sr ratios are measured at ∼0.710. In the Outer Zone, a zone with Cretaceous metamorphic rocks of the Sanbagawa Belt and Jurassic to Miocene accretionary complexes of the Chichibu Belt and Shimanto Belts, the 87Sr/86Sr ratios tend to fall in the range from 0.706 to 0.715, tend to increase from north to south, and are highest in the youngest accretionary complex of the Southern Shimanto Belt. The 87Rb/86Sr-87Sr/86Sr plots for stream sediments more clearly reveal the differences and similarities of their bedrocks, such as the different trends among the stream sediments of the Inner and Outer Zones. Samples collected from the Inner Zone show almost the same 87Rb/86Sr-87Sr/86Sr field as their source rocks, while most of the samples derived from accretionary complexes in the Outer Zone are plotted around a mixing line of older continental detritus and igneous-rock-derived materials. In light of the other geochemical characteristics observed, particularly the REE chemical features of the stream sediments and zircon ages in the basemental sedimentary rocks, the accretionary complexes in the Outer Zone may be mainly formed from the same source rocks, namely, igneous-rock-derived materials and continental detrital materials with different mixing ratios and a larger ratio of continental materials in the Southern Shimanto Belt. This study indicates that 87Sr/86Sr ratios of stream sediments strongly reflect the isotopic composition of the source rocks and are very useful for distinguishing the various geological and geochemical settings of the source rocks. © 2013, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

DOI： 10.2343/geochemj.2.0248

Scopus

CiNii Research

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

An AMS system (Model 4130-AMS) dedicated to14C measurements, built by High Voltage Engineering Europe (HVEE), B.V., The Netherlands, was delivered to Nagoya University in 1996/97. Acceptance tests of its performance on carbon isotope measurements were completed in January of 1999, and routine measurements began in mid-2000. Since completion of the acceptance tests in early 1999, we have encountered a lot of troubles with the machine, particularly in 2002. Since the end of 2002, the machine has worked relatively well, expect for minor problems. The standard deviation (one sigma) of the 14C/12C ratio is around ±0.3% to ±0.4% (a bit larger than the uncertainty of about ±0.3% calculated from 14C counting statistics) and that of the corresponding 13C/12C ratio is ±0.03% to ±0.07% ， as are tested for HOxII targets. The number of targets measured was 330, 1430, 2077, 1003, 1,979, 1679, 1772, 1115, 1339, 866, 1300, 1701, 1449, 1634 in each year from 1999 to 2012, respectively, and total number of targets measured by the end of 2012 is 19,674. The Tandetron AMS system worked well in the early half of 2012, with only minor failures. In September, a noise became large from the 12C-beam chopper, in the recombinator system, owing to the problem of a ferro-fluid-feedthrough, which had been used since June, 2008. We have replaced the ferro-fluid feedthrough to a new one. Soon after the chopper problem, the turbo molecular pump (TMP) in the recombinator system was damaged with the bearing of the rotating fan. We sent the pump to the supplier for repair. Because of the broken bearing, the rotating fan was seriously damaged, and we must purchase a new one. On 24th October, a large noise was generated from inside of the accelerator tank. We decided to open the tank and check the parts inside. The problem was also a bearing mounted in the power generator that supplies electric power to a terminal turbo-pump mounted inside the tank. We can get a new generator in a few weeks, because HVEE possessed one for spare by chance. We purchased it and replaced the damage generator on November. After tank opening, inner surfaces of the accelerator tank absorbed water in the atmosphere, we spent much time to remove water vapor from SF6 insulator gas. We had experienced twice of high voltage sparks, but no detectable damage occurred with the accelerator system. We could have restarted 14C measurements at around mid of December. Owing to these difficulties with the machine, the total number of graphite targets measured was 1634 in 2012, smaller in number than that in 2010 (1701), but a larger than in 2011 (1449).
名古屋大学年代測定総合研究センターシンポジウム報告

DOI： 10.18999/sumrua.24.13

記述言語：日本語   出版者・発行元：Geofluids  

In granitic rocks, fracture networks typically provide pathways for groundwater flow and solute transport that need to be understood to assess the long-term performance of deep underground storage or disposal facilities such as radioactive waste repositories. However, relatively little is known about the long-term processes of fracturing and/or the longevity of flow paths (FP) in granitic rocks distributed within orogenic belts. To clarify these issues, Japanese plutons of different ages and in situ fractures in granite at the Mizunami Underground Research Laboratory (MIU) located in central Japan were studied. Detailed structural characterization and geochemical analysis of in situ fracture fillings sampled from a depth of 300 m were carried out to clarify the relationship between fracturing and mineral infilling processes. Different plutons show identical episodes of fracturing and fracture filling, consisting of: brittle tensile fracturing, due to decreasing temperature through the ductile-brittle transition after plutonic intrusion (Stage I); relatively rapid uplifting (ca. a few mm/year) accompanied by hydrothermal water circulation, which produced uncrushed layered mineral fillings (Stage II); and a period of low-temperature meteoric water circulation following exposure after uplift (Stage III). The parageneses of carbonate mineral fracture fillings and their carbon isotopic compositions (14C, δ13C) show that there were distinct episodes of carbonate mineral precipitation during the rapid uplifting of a pluton. The carbonate minerals that formed during each episode incorporated carbon from a distinct source. The evolution of fillings identified here enables development of a specific model of fracturing and persistence of fluid-conducting systems in the plutons of the orogenic field. © 2012 Blackwell Publishing Ltd.

DOI： 10.1111/gfl.12008

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

As part of the ongoing development at the AMS facility of the Center for Chronological Research at Nagoya University to radiocarbon (14C) analyze samples smaller than 0.5 mg carbon (mgC), a compact graphitization manifold has been built. Tests with various reference materials show it performs well for samples as small as 0.1 mgC. Preparation with this new system is compared with the performance of the older protocol for regular-sized samples. Furthermore, it is shown that the addition of Cu and Ag before and stepwise heating during sealed-tube combustion of samples with high S content improve the degree of conversion to CO2 without having to resort to special purification measures such as the use of Co3O4 + Ag reagent and an n-pentane/LN2 trap before graphitization. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2012.02.036

Web of Science

Scopus

記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

Using data from previous studies and newly collected data, we compared the measured radiocarbon ages of molluscan shells, common reed (Phragmites australis) and pine needles (Pinus thunbergii) collected in 1966, 1970, 1990 and 2008 at Lake Biwa in Japan, and of archaeological samples, to examine radiocarbon reservoir effects at Lake Biwa. We also tested for differences in the radiocarbon reservoir effect between species and locations in the lake. The effects of nuclear bomb tests conducted in the 1950s and 1960s are clear, the offset between atmospheric 14C and the Lake Biwa freshwater 14C is larger for this period because the atmospheric 14C is so high. The semiclosed Lake Biwa system is in dynamic equilibrium with the atmosphere, resulting in the 14C content of the water following the changes in atmospheric 14C caused by nuclear testing. The shells collected after 1990 had radiocarbon ages that were 330-450 14C years older than those of the coeval atmosphere. The apparent differences in radiocarbon age (about 300 14C years) between shell fossils and wood samples excavated from the same layer of the submerged Awazu shell midden at Lake Biwa suggest that the radiocarbon reservoir effect also existed in the middle Holocene (the Middle Jomon period, about 5000 years ago). Because the present-day average residence time of Lake Biwa water is 3-6 years, its direct influence on the radiocarbon reservoir effect is small, which suggests that old carbon has been supplied into Lake Biwa. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2012.09.027

Web of Science

Scopus

記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

Ultrafiltration can effectively remove low-molecular-weight (LMW) contaminants from bone gelatin to extract high-molecular-weight (HMW) proteins that are derived from original bone collagen, though it cannot remove HMW collagen crosslinked with humic acids. Therefore, ultrafiltration is often used to obtain more accurate 14C dates of bones. However, ultrafiltration may introduce new contaminants to bone gelatins, mainly from ultrafilters used. To study the effects of ultrafiltration on 14C age, we analyzed the C/N ratio, δ13CPDB and δ15N AIR values, and 14C ages of acid-soluble bone collagen obtained by decalcification, gelatin extracted from acid-insoluble bone collagen, and the HMW gelatin and LMW fractions produced during ultrafiltration of the extracted gelatin. Bone samples from the Fifth International Radiocarbon Intercomparison (VIRI) were used: VIRI-E (mammoth), -F (horse), -G (human), and -I (whale). In this study, carbon and nitrogen content and gelatin yields were used to evaluate collagen preservation in the VIRI bone samples. Radiocarbon ages, δ13CPDB and δ15N AIR values of unfiltered and HMW gelatins were obtained and compared with the published consensus values. The LMW fraction was found to exhibit different values from those of the other fractions, indicating the possible presence of extraneous contamination. The Vivaspin™ 6 ultrafilters used in this study were analyzed and radiocarbon dated both before and after cleaning. We present evidence to suggest that LMW fraction contaminants could be derived from the ultrafilters rather than humic substances. Excessively long ultrafiltration time was suspected to have contaminated the bone samples with material from the ultrafilter, because those samples exhibited older 14C ages than did those filtered for shorter durations. The results in this study indicate that 14C ages of unfiltered gelatin extracted from well-preserved bones can be sufficiently accurate, and that care should be taken not to contaminate bone gelatin during ultrafiltration. Additional studies investigating bones with different degrees of degradation are needed to determine the effectiveness of ultrafiltration for accurate 14C dating when the collagen is not so well preserved. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2012.06.016

Web of Science

Scopus

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

水試料の14C分析のための前処理法としては、水試料にSrCl2等を添加して炭酸塩を生成させた後、リン酸を添加してCO2を発生させる方法が古くから用いられてきた。近年は、バブリングによって水試料中のCO2を分離抽出する前処理法が一般的であり、また、水試料を導入する容器のヘッドスペースを利用してCO2を抽出させる方法も導入されつつある。このように、水試料の前処理法に関して統一基準がないにもかかわらず、14C相互比較はこれまで行われていない。そこで我々は、炭素濃度・塩濃度の異なる共通の水試料（海水、温泉水、地下水など）を各機関に配布し、水試料の前処理法の違いによる14C比較を行うプロジェクト（RICE-W: Radiocarbon Intercomparison on Chemical Experiments, Water series）を立ち上げた。このプロジェクトについて紹介する。

DOI： 10.14862/geochemproc.60.0.101.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

秋吉石灰岩地域の河川堆積物（＜180μm）に石灰岩の元素濃度が反映されない要因について、粒径分画別<SUP>87</SUP>Sr/<SUP>86</SUP>Sr同位体比から考察した。その結果、1000－125μmの粗粒分画は石灰岩の既報値とほぼ同一のSr同位体比（0.7076－0.7088）を示したが、＜125μmの細粒分画では方解石が多く存在するものの異なる値を示すことが明らかになった。これは、粗粒分画では石灰岩が物理的風化した粒子の割合が高いが、細粒分画で見られる方解石は、一度化学的風化で溶けた方解石が二次的に生成されたものであり、細粒分画の同位体比は石灰岩中に不純物として含まれる鉱物起源に強く影響されている可能性を示す。よって、石灰岩由来の河川堆積物は、細粒分画において化学的風化に強い鉱物や二次生成された鉱物の化学組成を強く反映する場合もあるため、注意が必要である。

DOI： 10.14862/geochemproc.60.0.61.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

近年、大気粉塵中の炭素粒子の発生源を推定する方法の一つとして、<SUP>14</SUP>C濃度測定が注目されている。<SUP>14</SUP>C濃度により、炭素成分の起源は化石燃料起源とバイオマス起源に分けられ、実際の粉塵試料に対し<SUP>14</SUP>C濃度測定を行うことで、この２つの起源の寄与率が推定できる。また、δ<SUP>13</SUP>Cも発生源特定の手がかりとして有効と考えられる。偏西風の風下に位置する福岡は、アジア大陸からの輸送による影響を受けやすい地点であるため、福岡の大気中微小粒子状物質に対し<SUP>14</SUP>C濃度測定およびδ<SUP>13</SUP>C測定を行うことは、近隣での発生および長距離輸送の実態解明につながると考えられる。本発表では、2012年度に福岡市で観測されたPM<SUB>2.5</SUB>中全炭素(TC)における<SUP>14</SUP>C濃度およびδ<SUP>13</SUP>Cの通年の挙動について報告する。

DOI： 10.14862/geochemproc.60.0.112.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

本研究では，琵琶湖水が淡水リザーバー年代を示す原因を説明するために，湖水に対する古い炭素源の寄与を琵琶湖のシンプルな水理構造を利用してモデル計算を試みた。さらに，伊吹山系の湧水や姉川など河川水のDIC，DI14C濃度を測定し， Dead carbon sourceである伊吹山，霊仙山などの石灰岩地帯を起源とする河川水，地下水などから供給される古い炭素の影響を評価した。　豊富な魚介類や淡水を利用できるため，琵琶湖周辺では，先史時代から人々の生活が営まれていたことが知られている（水中遺跡は100ヶ所以上）。琵琶湖の水産資源を利用していた当時の（人間を含む）動物が，淡水リザーバー効果の影響を強く受けていたことが示唆される。発表では，現生生態試料を用いて，貝殻と（可食部である）身の炭素年代差，代表的な湖のリザーバー年代も含めて，考古学試料の炭素年代測定に関する淡水リザーバー効果の影響に関しても議論する。

DOI： 10.14862/geochemproc.60.0.226.0

CiNii Research

J-GLOBAL

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）  

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：GEOCHEMICAL SOC JAPAN  

Geochemical mapping of Sr-87/Sr-86 ratios in Shikoku Island and the Kii Peninsula of Southwest Japan was performed using 233 samples of stream sediments (&lt;180 mu m). The spatial distribution of Sr-87/Sr-86 ratios successively increases from northern to southern geological units, with a gap at the Median Tectonic Line (MTL). In the Inner Zone divided by the MTL, a zone with Cretaceous granitoid rocks of the Ryoke Belt and sedimentary rocks of the Izumi Group, the Sr-87/Sr-86 ratios are measured at similar to 0.710. In the Outer Zone, a zone with Cretaceous metamorphic rocks of the Sanbagawa Belt and Jurassic to Miocene accretionary complexes of the Chichibu Belt and Shimanto Belts, the Sr-87/Sr-86 ratios tend to fall in the range from 0.706 to 0.715, tend to increase from north to south, and are highest in the youngest accretionary complex of the Southern Shimanto Belt.
The Rb-87/Sr-86-Sr-87/Sr-86 plots for stream sediments more clearly reveal the differences and similarities of their bedrocks, such as the different trends among the stream sediments of the Inner and Outer Zones. Samples collected from the Inner Zone show almost the same Rb-87/Sr-86-Sr-87/Sr-86 field as their source rocks, while most of the samples derived from accretionary complexes in the Outer Zone are plotted around a mixing line of older continental detritus and igneous-rock-derived materials. In light of the other geochemical characteristics observed, particularly the REE chemical features of the stream sediments and zircon ages in the basemental sedimentary rocks, the accretionary complexes in the Outer Zone may be mainly formed from the same source rocks, namely, igneous-rock-derived materials and continental detrital materials with different mixing ratios and a larger ratio of continental materials in the Southern Shimanto Belt. This study indicates that Sr-87/Sr-86 ratios of stream sediments strongly reflect the isotopic composition of the source rocks and are very useful for distinguishing the various geological and geochemical settings of the source rocks.

Web of Science

担当区分：筆頭著者   記述言語：日本語  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Web of Science

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

本研究においては、植物の部位によって同位体比が一致しているかどうかや、生育地周辺の地質の同位体比とどの程度一致するかを明らかにするために、愛知県北東部のイネを対象例とし、根・茎・葉・籾（玄米・糠・白米）の各部位のSr同位体比を調べた。また、イネのSr同位体比が水田の土、水、および周辺の河川堆積物のSr同位体比とどのような関係にあるか調べた。Sr同位体比の測定は名古屋大学の表面電離型質量分析計（Sector 54-30）により行なった。イネの試料について、個体差や試料の不均一性はほとんどなく、部位毎のSr同位体比は、白米を除いてその差は0.0002程度であった。また、水田の水、土の交換性SrのSr同位体比はイネの値とほぼ一致したが、土のバルクSrはイネよりも高い値を示した。近くの河川堆積物、イノシシの骨も同じSr同位体比の幅の範囲内となった。以上のことから、河川堆積物の交換性Srの同位体比は産地判別のための地域の代表値として有効である可能性が示唆された。

DOI： 10.14862/geochemproc.59.0.234.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

泥炭堆積物は過去数百年から数千年の大気由来の重金属元素の降下の歴史を探る上で有用な試料である．その理由は，泥炭は自然由来の重金属元素の含有量が低いこと，重金属元素の保持力が高いことにある．泥炭の有機物含有量は高いことから，この堆積年代決定には<SUP>14</SUP>C法が利用されることが多い．本研究では，過去数百年から数千年のユーラシア大陸から日本列島，北太平洋への越境鉛の歴史的変遷を解明することを目的とし，2009年に北海道利尻島沼浦湿地オタドマリ沼から40 cm長の泥炭コアを採取した．このコアの堆積年代決定のために，本研究においても<SUP>14</SUP>C法を適用した．具体的には，泥炭コア試料中の有機物，植物片試料に対しAAA処理を施し，<SUP>14</SUP>C年代測定を行った．さらに，<SUP>14</SUP>C年代値の信頼性を確認するために，コア表層部の<SUP>210</SUP>Pbおよび<SUP>137</SUP>Csの測定も行った．

DOI： 10.14862/geochemproc.59.0.218.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

地表面の情報を集約する、粒径が180?m以下の河川堆積物を用い、北海道の<SUP>87</SUP>Sr/<SUP>86</SUP>Sr同位体比分布を明らかにした。まず、試料の不均質性を評価するため、量り取りからの測定までを独立した作業として5回行い、測定値の標準偏差を求めた。その結果、比較的粗粒であっても、不均質性は測定値にほとんど影響を与えない程度であることが明らかになった。北海道の試料からは、0.703から0.711までのSr同位体比を得た。特徴的であったのは、隣り合う空知-エゾ帯と日高帯において採取された試料が異なる値の範囲を示したことである。これは、両帯が以前は離れて位置しており、古東北日本弧と古千島弧からの砕屑物の供給率が異なるという既存の研究結果と整合するものであり、以上のことは、河川堆積物のSr同位体比が母岩の組成とよく一致することを示している。

DOI： 10.14862/geochemproc.59.0.60.0

CiNii Research

記述言語：日本語   出版者・発行元：公益社団法人 日本化学会  

DOI： 10.20665/kakyoshi.60.11_472

CiNii Books

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

AMS-<SUP>14</SUP>C測定では通常1.0－1.5 mgの炭素量(mgC)で測定が行なわれている。しかし近年、?Cレベルでの<SUP>14</SUP>C測定の需要が高まっている。本研究では微少量炭素試料のための新たなグラファイト化システムを構築し、まず～0.2mgCでの信頼性のある<SUP>14</SUP>C測定の実現を目指した。新しいシステムではグラファイト化の反応を高めるため、1) 反応器の容積の小型化、2) 還元剤H<SUB>2</SUB>量の増大、3) 副生成物H<SUB>2</SUB>Oの除去を常温冷却からエタノール/LN<SUB>2</SUB>トラップ(－90℃)による急冷に変更、の3点の改良を行った。その結果、0.2 mgC以上での信頼性のある<SUP>14</SUP>C測定を実現できることが明らかになった。

DOI： 10.14862/geochemproc.59.0.132.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

本研究では，縄文時代後半期，海産物に依存していた海岸近くに暮らしていた人々の生活を，遺跡出土土器に残存する有機物組成を用いて復元することを目的とする。愛知県渥美半島にある保美貝塚から出土した土器残存有機物の脂質組成から，土器で海産物を含む食材を煮炊きしていた可能性を強く支持する結果が得られた。この結果は，土器付着炭化物の年代測定結果から海洋リザーバー効果が検出され，付着炭化物の安定同位体組成から，海獣や海産魚類を調理した可能性が示唆されたことも調和的である。

DOI： 10.14862/geochemproc.59.0.333.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

Sr同位体比（87Sr/86Sr）を指標として、農作物の産地推定や、遺跡から出土された人の骨・歯から生育地を推定する研究が近年広く行われている。この研究の基盤として、地質表層のSr同位体比が既知であることが必要不可欠である。地質のSr同位体比分布を求めるため、我々は河川堆積物に着目した。流域に分布する多様な岩石の集合体である河川堆積物は、その地点を含めた上流域の様々な情報を平均化しており、表層のSr同位体比分布を明らかにするのに有用と考えられる。試料としては、産総研が元素濃度の地球化学図作成に用いた全国の河川堆積物を用いた。本講演においては、河川堆積物を用いた全国地質表層Sr同位体比マップが、農作物の産地推定、過去の人類の移動解明のための基礎データとして有用かどうかを論ずる。

DOI： 10.14862/geochemproc.59.0.331.0

CiNii Research

記述言語：日本語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：JAPAN ASSOC AEROSOL SCI & TECHNOLOGY  

Total suspended particles (TSP) were collected in spring (2011) in Nagoya and Fukuoka. The samples were analyzed for contents of inorganic ions, organic carbon (OC), and elemental carbon (EC), and delta C-13 value of total carbon. The results demonstrate that the calcium ion concentration and delta C-13 value of total carbon increased during the Asian dust storm events. In May 3, the ration of carbon derived from carbonate in total carbon was at maximum, and delta C-13 of total carbon showed the largest value. The results indicate that carbon derived from carbonate had been reacted with acidic species (such as H2SO4, HNO3 etc...) in the atmosphere during a long-range transport.

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本学士院  

AMS (Accelerator Mass Spectrometry) radiocarbon dates for eight potsherds from a single piece of pottery from a wetland archaeological site indicated that charred material from the inner pottery surfaces (5052 ' 12 BP; N F 5) is about 90 14C years older than that from the outer surfaces (4961 ' 22 BP; N F 7). We considered three possible causes of this difference: the old wood effect, reservoir effects, and diagenesis. We concluded that differences in the radiocarbon ages between materials from the inner and outer surfaces of the same pot were caused either by the freshwater reservoir effect or by diagenesis. Moreover, we found that the radiocarbon ages of carbonized material on outer surfaces (soot) of pottery from other wetland archaeological sites were the same as the ages of material on inner surfaces (charred food) of the same pot within error, suggesting absence of freshwater reservoir effect or diagenesis. © 2011 The Japan Academy.

DOI： 10.2183/pjab.87.518

Web of Science

Scopus

PubMed

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

出版者・発行元：一般社団法人日本地球化学会  

自然界における元素の地球化学サイクルを利用して人為起源の二酸化炭素や大気中の二酸化炭素を吸収・固定する様々な試みがなされている。そこでの問題のひとつは、HCO₃^-を無機化学的にCa2⁺と結びつけ、CaCO3として沈殿させると、反応式からは当量のCO₂が解離する事である。更には，解離したCO₂がHCO₃^-として再度水に溶解するならH＋が生じ、溶液が酸性化し、その後にCO₂が溶け込みにくくなるであろう事も問題とされている。これを補うのは，ケイ酸塩鉱物の分解（風化）反応と考えられるが、風化反応が起こる場所と反応時間の長さが工学的観点からの二酸化炭素固定における問題点とされる。演者らは、石灰質砂岩の中に海水からのCaCO3無機固定とケイ酸塩の分解が同一場所でほぼ同時におこったと考えられる地質場を見いだした。

DOI： 10.14862/geochemproc.58.0.185.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

我々は，日本における表層の⁸⁷Sr/⁸⁶Sr同位体比の分布を明らかにすることを目的とし，これまでに九州地方，四国地方，紀伊半島における⁸⁷Sr/⁸⁶Sr比地球化学図を作成してきた。本講演においては，中国地方における河川堆積物175試料の⁸⁷Sr/⁸⁶Sr比の測定を行ない，中国地方の表層の⁸⁷Sr/⁸⁶Sr比分布を報告する。また，採取する地点の堆積物の不均質性，化学組成の経年・季節変化を調べるため，1994年から毎年同一地点で採取された愛知県瀬戸市矢田川定点の河川堆積物（計69試料）についても⁸⁷Sr/⁸⁶Sr比を測定し，一堆積物試料の⁸⁷Sr/⁸⁶Sr比が採取地点の地質の⁸⁷Sr/⁸⁶Sr比をどの程度代表しているかについても検討を行う。

DOI： 10.14862/geochemproc.58.0.380.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

コンクリート構造物の中性化時期を推定するため，昭和40年代に建築された実構造物のコア試験体の¹⁴C濃度，炭素・酸素同位体比の深度変化を調べた．最表層部の14C濃度は139～148 pMCであり，深部では71～86 pMCであった．これらの深度プロファイルから以下の結論が得られた．(1) ¹⁴C，炭素・酸素同位体比のデータから，コア試験体深部のCO₂は建築時に初生的に取り込まれたものであり，セメント由来のCO₂（主に石灰岩起源）とコンクリート硬化時に初生的に固定されたCO₂（1967年の大気起源）の2成分の混合物であることが明らかとなった．(2) 表層部のCO₂について，建築時の初生的なCO₂を補正し，建築後に吸収されたCO₂の量と¹⁴C値を求めた．この14Cの補正値を，大気CO₂の¹⁴C濃度の経年変動データと対比したところ，表層部の中性化は建築後2～4年の間に進行していたことが明らかになった．

DOI： 10.14862/geochemproc.58.0.137.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

近年、東アジア諸国から日本列島・太平洋への越境汚染が問題視されているが、その歴史的変遷は明らかになっていない。本研究は、北海道利尻島で採取した泥炭コアの鉛濃度、鉛同位体比から過去5000年間に大気輸送された鉛の供給源解析を行った。その結果、640 cal BC頃から人為起源鉛が堆積し、越境輸送が始まっていたことが確認された。同位体組成は中国南部の鉛鉱石の寄与を示唆している。1430 cal AD以降、鉛の輸送量はさらに増加する。中国北部の鉛鉱石、石炭の使用が寄与していると考えられるが、同時に、日本で使用されたオーストラリア産の鉛鉱石が寄与している可能性も考えられる。

DOI： 10.14862/geochemproc.58.0.114.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

本研究では，礼文島浜中２遺跡Ｖ層出土土器胎土に残存する有機物をBristol大学で脂質分析し，海獣を起源とする有機残渣が検出されるかどうか検討した。その結果，炭素数14～22までの飽和脂肪酸が検出されると同時に，炭素数C16:3,18:3,20:3,22:3などのトリ不飽和脂肪酸（陸上動物や植物油と比べて，海洋性動物由来の油脂に占める割合は非常に高い）の加熱生成物と推定される環状化合物（ω-(o-alkylphenyl) alkanoic acids)が検出された。さらに，海洋性動物の存在の証拠と考えられているPhytanic acidやPristanic acidも検出された。このことは，縄文時代後期（1300～1200 BC）に，本遺跡で，これらの土器でニホンアシカを調理した際に，ニホンアシカの肉はコゲとして内面土器炭化付着物になり，燃料材に由来するススが外面土器付着炭化物として付着した。また，加熱によって生成するこれらの環状化合物は，土器でニホンアシカを調理した可能性を示唆する証拠であり，海洋性動物の指標として考えられるイソプレノイド化合物とともに土器に吸着され，現代検出されたものと考えられる。

DOI： 10.14862/geochemproc.58.0.300.0

CiNii Research

J-GLOBAL

出版者・発行元：一般社団法人日本地球化学会  

河川堆積物の粒径180μm以下のフラクションの⁸⁷Sr/⁸⁶Sr同位体比が，その地域の地質の代表値とみなしうるかどうかを明らかにするために，河川堆積物を6つの粒径区分で区切り，各粒径フラクションのSr濃度，⁸⁷Sr/⁸⁶Srを調べた。その結果Sr濃度は粒径による差はほとんど見られず，また同位体比に関しても，180μm以下のフラクションであれば，フラクション間の同位体比の差は，地質の異なる採取地点間の差に比べて小さく，粒径の違いは同位体比には影響しないと考えられる。よって粒径180μm以下の河川堆積物は採取地点周辺の地質を集約する⁸⁷Sr/⁸⁶Sr 同位体比をもっており，地質の代表値とみなしうると考えられる。

DOI： 10.14862/geochemproc.58.0.314.0

CiNii Research

出版者・発行元：日本化学会  

出版者・発行元：日本化学会  

記述言語：日本語   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

For a preliminary test of 14C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS 14C dating, carbon and nitrogen contents, δ13C and δ15N values of the fragments. All 14C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some 14C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older 14C ages, most probably as the result of old wood effect. © 2009.

DOI： 10.1016/j.nimb.2009.10.080

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：一般社団法人 日本地質学会  

DOI： 10.14863/geosocabst.2010.0.543.0

CiNii Research

J-GLOBAL

記述言語：日本語   出版者・発行元：一般社団法人 セメント協会  

本検討では、名古屋市内の構造物のコア試験体に対して、放射性炭素に関する分析を行い、コンクリートの中性化現象について考察を行った。その結果、コンクリートの中性化現象について¹⁴C濃度を評価した結果、表層で濃度が高く、内部で低くなる傾向が得られた。また、¹⁴C濃度の経年変化プロファイルを参照することで、建設年代の情報があれば、中性化の進行プロセスを推定できる可能性があることがわかった。また、¹⁴C濃度は、フェノールフタレインの呈色反応によって評価される中性化フロントよりもかなり奥まで高い数値を保持しており、この値は、材料由来か、あるいは深部までCO₂が到達したことによると考えられた。

DOI： 10.14250/cement.64.139

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

大気中の二酸化炭素は，近年急速に増加していることが観測の結果明らかとなっており，地球温暖化を促進する気体の一つとして，増加の抑制が世界規模で討議されているところである．大気中の二酸化炭素の増加は，二酸化炭素濃度の直接的測定で明らかにできるが，また，植物に固定された炭素の14C濃度を測定することで，Suess効果（化石燃料の消費により大気中に放出される，14Cを含まない二酸化炭素による大気中二酸化炭素濃度の希釈効果）として検出される．ここでは，2005, 2008, 2009年に名古屋大学東山キャンパス内で形成された松葉試料を中心に，環境14C濃度の経年変動や場所依存性を議論する．

DOI： 10.14862/geochemproc.57.0.167.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

コンクリートの中性化進行の定量的な指標として放射性炭素（14C）を新たに提案し、14Cの化学的定量性・感度、および反応時間の指標としての検討を行ってきている（淺原ほか, 2009； 丸山ほか, 投稿中）。その結果、14C濃度は、フェノールフタレインの呈色反応によって評価される中性化フロントよりもかなり奥まで変化しており、中性化プロセスは単純ではないものの、14Cを用いることでコンクリートの中性化進行プロセスを推定できる可能性があることが明らかになった。これらの知見のうち、本講演においては、実構造物のコンクリートの表層の中性化領域から深部の未中性化領域にかけての元素移動の観察結果について報告する。

DOI： 10.14862/geochemproc.57.0.35.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

四国・紀伊半島地域における<SUP>87</SUP>Sr/<SUP>86</SUP>Sr同位体比地球化学図を作成したところ、付加年代が新しい四万十帯の南帯において、一番高い値（0.718～0.720）が得られた。付近に分布するジュラ紀付加体を考慮しても、そこまで値が高められるとは考えにくく、大陸起源の砕屑物の影響を考えたほうが自然である。そこで四万十帯中に古い年代をもつ砕屑性ジルコンが存在するかを明らかにするため、四国東部の四万十帯北帯・南帯の累層ごとに砂岩を採取し、砂岩中のジルコンのCHIME年代測定を行った。その結果、南北両帯において1100Maや2000Maなどのジルコンの年代値が得られ、四万十帯の源岩として大陸基盤岩が含まれていることが示唆された。またそれにより<SUP>87</SUP>Sr/<SUP>86</SUP>Sr同位体比の値が高められていると考えられる。

DOI： 10.14862/geochemproc.57.0.277.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

先史時代の食生活を復元するために，飛行時間型二次イオン質量分析法（Time-of-flight secondary ion mass spectrometry：TOF-SIMS）を用いて，土器に残存する有機物分子を分子レベルで直接同定し（非破壊分析），調理された食材を推定することが可能であるかどうか検討した．

DOI： 10.14862/geochemproc.57.0.147.0

CiNii Research

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

出版者・発行元：一般社団法人日本地球化学会  

近年、イネなどの植物の産地同定の手段として87Sr/86Sr同位体比が用いられるようになり、さらに、遺跡から出土された人骨の87Sr/86Sr同位体比を測定して、その遺跡に埋葬されている人の出身地を推定することも行われつつある。地質の87Sr/86Sr同位体比は、そこで生育している植物の、最終的には動物の骨中に反映されると考えられ、87Sr/86Sr同位体比の地球化学図は、生育場の同定などを行う際の基礎データとして重要である。我々は、河川堆積物を主として用い、全国の87Sr/86Sr同位体比の地球化学図を作成することを目的としている。昨年の年会では、九州北部・西部地域の87Sr/86Sr同位体比の分布を報告した（後藤ほか、2008）。本講演では、九州の南部・東部を含めた九州全域、ならびに四国地域の87Sr/86Sr同位体比分布を報告する。

DOI： 10.14862/geochemproc.56.0.210.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

名古屋のクロマツ年輪中の炭素・酸素安定同位体、および放射性炭素同位体比の測定を行い、これらの同位体比の変動がどの気象要素の影響を強く受けているのか、また気象要素以外の環境要因による影響が存在するのかどうかの検討を試みた。その結果、δ13Ｃ・δ18Ｏはともに、相対湿度と強い負の相関がみられた。また、Δ14Ｃについては、1964年の高濃度のピークが示され、大気と樹木年輪中の同位体比の変動がほぼ一致し、生育時に吸収された同位体比がそのまま年輪の成長に反映されることがわかった。

DOI： 10.14862/geochemproc.56.0.129.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

コンクリートは、質・量ともに現代社会を支える重要な物質材料である。しかし、この人工岩石とも言える材質の長期的な変質プロセスについては、未だよく理解されていない。コンクリートの劣化は、セメントに含まれる石灰分と、水＋大気中のCO2の化学反応（中性化）に伴う組織劣化である。我々は、コンクリートの組織劣化の定量的な指標として放射性炭素（14C）を新たに提案し、14Cの化学的定量性・感度、および反応時間の指標としての適用可能性についての検討を行っている。本講演においては、特に、宮城県東北部の本吉郡南三陸町歌津海岸、館浜と浪板の地点に露出する石灰質砂岩を用い、長期的なコンクリート劣化のアナログ的調査を行った結果について紹介する。

DOI： 10.14862/geochemproc.56.0.259.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

社会基盤を支えるコンクリート構造物は、その長期耐久性が期待されている一方、早期劣化が大きな問題ともなっている。コンクリートの主な劣化要因のうち、中性化はすべてのコンクリート構造物に関わる現象である。中性化は、コンクリートのセメント水和物と大気の二酸化炭素が反応することにより進行することから、コンクリート中の炭素の挙動は組織あるいは物理強度の変化を直接反映すると考えられる。この組織劣化の指標として、その化学的定量性・感度から信頼性が高く、かつ反応時間の指標としても適用可能な放射性炭素14Cに着目する。本研究では、耐震改修工事の進む名古屋大学校舎を利用し、14C法によるコンクリートの約40年間の定量的劣化度評価の可能性を検討した。

DOI： 10.14862/geochemproc.56.0.63.0

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人日本地球化学会  

表記地域から，約２０００試料の河床堆積物を採集し，蛍光X線分析と中性子放射化分析により，それらの主／微量成分３８元素を分析した。また、同一地点で多数のグループが試料を採集したり、毎年試料を採集し，その変動を調べる等、分析試料の代表性も検討した。そのけっか、ナトリウム、カルシウム、アルミニウム等の分布は、花崗岩の分布に一致することがわかった。鉄の分布はマグネシウムの分布に一致する所としないところがあり、後者は、ゴルフ場の分布に一致することがわかった。ヒ素の分布は金の分布に一致する所としないところがある。前者は熱水鉱床の存在を示す。

DOI： 10.14862/geochemproc.56.0.205.0

CiNii Research

J-GLOBAL

記述言語：日本語   出版者・発行元：Journal of Nuclear Science and Technology  

We have considered the applicability of strontium isotope analysis, using Laser Ablation-assisted Resonance Ionization Mass Spectrometry (LA-RIMS), to the determination of bone origin. We separated the uncertainty into two categories: ion counting statistics, and short-term or uncontrollable shifts of experimental conditions; only the former decreases with increasing signal intensity. Additionally, we confirmed that long-term shifts of isotope ratio in LA-RIMS can be cancelled by an internal correction method. We preliminarily estimated the precision of our technique to be 0.7% (1σ) for 105 laser shots; the accuracy is also confirmed within the present uncertainty through the comparison with a reference value. © 2008 Atomic Energy Society of Japan. All Rights Reserved.

DOI： 10.1080/00223131.2008.10875986

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Scopus

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

昨年度(平成18(2006)年度)には、センター設立から7年間の研究教育活動を総括し、今後に取り組む課題を検討するために、年代学研究を専門とする外国人研究者5名と日本人研究者2名による外部評価、ならびに自己点検・評価を実施し、3月に外部評価・自己点検評価報告書「年代測定総合研究センター 外部評価・自己点検評価報告書-最先端の地球年代学研究を推進-」を発刊致しました。今年度(平成19(2007)年度)の年代測定総合研究センターシンポジウムでは、この外部評価を受けて、-年代測定総合研究センターの将来展望-という題目で、自由討論を行いました。また、活発な共同利用を目指すため、共同利用者の方々に「名古屋大学タンデトロン加速器質量分析計学内共同利用に関するアンケート」を実施致しました。そのまとめを以下に記します。第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.169

CiNii Books

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\nin 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.66

CiNii Books

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.117

CiNii Books

出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.160

出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.110

出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.26

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 平成19 (2007)年度

DOI： 10.18999/sumrua.19.175

CiNii Books

出版者・発行元：名古屋大学年代測定資料研究センター  

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 平成19 (2007)年度

DOI： 10.18999/sumrua.19.190

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall

DOI： 10.18999/sumrua.19.39

CiNii Books

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

出版者・発行元：一般社団法人日本地球化学会  

河川堆積物の化学組成分布を地図上に表示した地球化学図は、自然由来や人為的な事象に関わる化学組成を反映していると考えられ、地表での環境指標となりうる。近年、イネやネギなどの植物の産地同定の手段としてSr同位体比が用いられるようになり、さらに、遺跡から出土された人骨のSr同位体比の測定による出身地の推定が行われつつある。地質のSr同位体比は、そこで生育している植物の、最終的には動物の骨中に反映されると考えられ、Sr同位体比の地球化学図は、生育場の同定などを行う際の基礎データとして重要である。本研究では、全国のSr同位体比の地球化学図を作成することを目的とし、九州北部と中部地域の河川堆積物を試料として、この地域のSr同位体比の分布を明らかにし、河川堆積物のSr同位体比が河川流域の地質環境を反映しているかどうかを調べた。

DOI： 10.14862/geochemproc.55.0.382.0

CiNii Research

出版者・発行元：一般社団法人日本地球化学会  

これまで、鎌倉由比ヶ浜地域の遺跡から出土する大量の中世人骨は、数千人におよぶ死者を出したと考えられている新田義貞の鎌倉攻めの合戦（1333年）によって死没した人々のものと推察されてきた。我々はこれまでに、由比ヶ浜南遺跡、中世集団墓地遺跡から出土した人骨の放射性炭素（14C）年代を測定し、いずれの人骨試料も鎌倉幕府終焉より古い14C年代を示す傾向が見られることを報告した。しかし、埋葬されている人達は海産物を食しており、14Cの海洋リザーバー効果により、得られた骨の14C年代が実際の年代より古い可能性が考えられた。そこで、本研究では、モンテカルロ法を用いた海産物の摂取割合算出プログラムによりδ13C値、δ15N値からMarine%を算出し、Marine04/IntCal04データセットによるMarine混合曲線によって較正年代を求め、さらに確かな年代を算出する試みを行った。

DOI： 10.14862/geochemproc.55.0.325.0

CiNii Research

記述言語：日本語   出版者・発行元：Precambrian Research  

A diverse assemblage of indigenous carbonaceous microstructures, classified here as highly probable microfossils to pseudomicrofossils, is present in the >ca. 2.97 Ga Farrel Quartzite (Gorge Creek Group) at Mount Grant and Mount Goldsworthy, Pilbara Craton, Western Australia. The microstructures are an integral part of the primary sedimentary fabrics preserved in black chert beds. The interbedding of chert with layers of large silicified crystal pseudomorphs and fine to coarse grained volcaniclastic/clastic beds indicate deposition in a partially evaporitic basin with terrigenous clastic and volcaniclastic input. Similar associations of microstructures are present at the same stratigraphic level in outcrops more than 2 km apart. Four major microstructural types are present: thread-like, film-like, spheroidal and lenticular to spindle-like, each of which can be further subdivided into several sub-types. Most of the microstructures were deposited as part of an assemblage of chemical and clastic sediments, although there are some thread-like microstructures present for which a synsedimentary origin cannot be confirmed. Many specimens appear to have originally had flexible but breakable walls and some occur in colony-like aggregations. Size distributions for the four major types are generally narrow, a feature typical of biogenic structures. The microstructures are composed of disordered carbon (as revealed by Raman spectroscopy) and the bulk isotopic composition of the carbon is δ13C < -30 per mil, which is consistent with biological processing. The combined morphological and geological evidence suggests that the film-like structures, small spheres associated with films, large spheroids and spindle-like structures are probable to highly probable fossil remains of microorganisms. The morphological variety among the microstructures suggests that a diverse microbial ecosystem flourished in the Pilbara region during the Archaean. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.precamres.2007.03.006

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Scopus

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

An AMS system dedicated to 14C measurement (486-AMS) built by HVEE B.V. The Netherlands, was delivered to Nagoya University in 1996, and is in use for routine 14C measurements. The relative error of the standard deviation (1σ) of 14C/12C ratios is ±0.3% to ±0.5% (somewhat larger than the uncertainty of ±0.3% from 14C counting statistics) and that of the corresponding 13C/12C ratios is ±0.03% to ±0.07%, as measured for HOxII standards. By using this AMS system, we are now testing whether the recommended IntCal04 14C calibration data set is consistent with the natural 14C-concentration variations as recorded in Japanese trees. Here we report the results of these consistency tests and accurate age determination of tree rings grown in Japan, using the 14C wiggle matching technique. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2007.02.005

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Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

Paired marine and terrestrial samples were collected at archeological shell mounds in Kagoshima, Saga and Aichi prefectures and selected from sediment samples bored at the Mawaki archeological site in Ishikawa prefecture, to evaluate the local marine reservoir effect in Japan. The local reservoir corrections, ΔR, were evaluated to be 8 ± 110 and -178 ± 113 14C years for Miyasaka shell mound, -125 ± 50 to -45 ± 49 and -86 ± 48 to -21 ± 50 14C years for Higashimyo shell mound, -46 ± 52, 40 ± 44, -136 ± 44 and 100 ± 44 14C years for Yoshigo shell mound, -255 ± 38 and -146 ± 46 14C years for Kuzubasama shell mound, -71 ± 33, -30 ± 85 and -78 ± 74 14C years on average for C4, C5 and C6 cores, respectively, from the Mawaki site. The existing data along with the present results suggest that the ΔR values obtained for central to southern part of Japan are consistent with zero or a bit negative, but are different from the ΔR values of 200 to 500 14C years for the northern parts of the Japanese archipelago. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2007.01.186

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Scopus

出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第1部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.55

記述言語：英語   出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第1部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.53

CiNii Books

出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第1部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.31

出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<POSTER SESSION> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.83

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<POSTER SESSION> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.73

CiNii Books

記述言語：日本語   出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第2部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.91

CiNii Books

出版者・発行元：名古屋大学年代測定資料研究センター  

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第2部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research\in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall

DOI： 10.18999/sumrua.18.134

記述言語：日本語   出版者・発行元：Applied Geochemistry  

Since 1994 a geochemical mapping project has been undertaken in Aichi prefecture, central Japan, with the aim of establishing a database to contribute to environmental assessment in the region. To date more than 1200 stream sediments have been collected and analyzed. The samples were analyzed for 10 major elements by X-ray fluorescence spectrometry and loss-on-ignition. The analyses show that stream sediments from areas with sedimentary bedrock are enriched in SiO2 and mafic elements such as TiO2 and Fe2O3 compared to areas with granitic bedrock. The SiO2 enrichment is mainly due to the amount of quartz and the enrichment in mafic elements is due to biotite, both of which are derived from the sedimentary bedrock. In contrast, sediments derived from granitic bedrock are characterized by high abundances of elements contained in feldspars such as Na2O and CaO. This contrast in elemental distribution (e.g., Na2O/TiO2 ratio) can be useful for geological mapping in the areas covered by vegetation and with poor bedrock exposure. The relative abundances of Ca, Na and K in the stream sediments suggest that the Inagawa granite, one of the main granite bodies in the study area, can be classified into four distinct types. This classification is distinct from previous classifications based on geological and petrochemical studies. It is confirmed that analysis of geochemical compositions of stream sediments has considerable potential as a tool in geological studies including lithological mapping. © 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apgeochem.2006.09.011

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