研究者詳細 - 南　雅代

論文 - 南　雅代

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Syngenetic rapid growth of ellipsoidal silica concretions with bitumen cores 査読有り国際共著

Yoshida Hidekazu, Kuma Ryusei, Hasegawa Hitoshi, Katsuta Nagayoshi, Sirono Sin-iti, Minami Masayo, Nishimoto Shoji, Takagi Natsuko, Kadowaki Seiji, Metcalfe Richard

SCIENTIFIC REPORTS 11 巻 ( 1 ) 頁： 4230 2021年2月

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

Web of Science

Scopus

PubMed

Characteristics in trace elements compositions of tephras (B-Tm and To-a) for identification tools 査読有り

WATANABE NARA FUMIKO, YOKOYAMA TATSUNORI, YAMASAKI SHIN-ICHI, MINAMI MASAYO, ASAHARA YOSHIHIRO, WATANABE TAKAHIRO, YAMADA KAZUYOSHI, TSUCHIYA NORIYOSHI, YASUDA YOSHINORI

55 巻 ( 3 ) 頁： 117 - 133 2021年

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

火葬骨・木炭の放射性炭素年代測定

南雅代

松原市立部遺跡発掘調査報告書ー巻頁： 68 - 72 2021年

土壌資料のストロンチウム同位体分析

若木重行, 南雅代

松原市立部遺跡発掘調査報告書ー巻頁： 78 - 80 2021年

人骨のストロンチウム同位体分析

若木重行, 南雅代

松原市立部遺跡発掘調査報告書ー巻頁： 73 - 77 2021年

Sequential magma injection with a wide range of mixing and mingling in Late Jurassic plutons, southern Ghorveh, western Iran 査読有り国際共著

Azizi Hossein, Asahara Yoshihiro, Minami Masayo, Anma Ryo

JOURNAL OF ASIAN EARTH SCIENCES 200 巻 2020年9月

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

Variability of protoliths and pressure-temperature conditions of amphibolites from the Ohmachi Seamount (Izu-Bonin-Mariana arc): evidence of a fossil subduction channel in a modern intra-oceanic arc 査読有り

Imayama Takeshi, Ueda Hayato, Usuki Tadashi, Minami Masayo, Asahara Yoshihiro, Nagahashi Toru

MINERALOGY AND PETROLOGY 114 巻 ( 4 ) 頁： 305 - 318 2020年8月

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

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Scopus

Rapid formation of gigantic spherical dolomite concretion in marine sediments 査読有り

Muramiya Yusuke, Yoshida Hidekazu, Kubota Kaoru, Minami Masayo

SEDIMENTARY GEOLOGY 404 巻頁： 105664 - 105664 2020年7月

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

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Scopus

巨石のSr同位体比と埋没木片の14C年代からみた前橋泥流. 査読有り

南雅代

群馬県立自然史博物館研究報告 24 巻頁： 31 - 42 2020年6月

榛名・小野子・子持火山の基盤を構成する火山岩類の岩石化学的特徴：天然記念物「岩神の飛石」との比較査読有り

佐藤興平・南雅代

群馬県立自然史博物館研究報告 24 巻頁： 43 - 52 2020年3月

関東山地北西縁の下仁田地域に産する南蛇井層：ジルコンのU−Pb年代による予察招待有り査読有り

佐藤興平・竹内　誠・李　雨嘯・南　雅代・柴田　賢

群馬県立自然史博物館研究報告 24 巻頁： 53 - 70 2020年3月

Investigation of rare earth elements (REEs) as exploration potential in Intrusive bodies in the northern Sanandaj-Sirjan zone (Kurdistan area), western Iran 国際共著

Azizi Hossein, Maghsoudloo Ali, Nouri Fatemeh, Asahara Yoshihiro, Yamamoto Koshi, Minami Masayo, Tsuboi Motohiro

GEOCHEMICAL JOURNAL 54 巻 ( 4 ) 頁： 221 - 232 2020年

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

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.

DOI： 10.2343/geochemj.2.0584

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Scopus

CiNii Research

Radiocarbon dating of cremated bones from the Ishibotoke-dani of Binman-ji Temple in Taga, Shiga Prefecture, Japan: A preliminary report. 国際共著

南雅代

Proceedings of EA-AMS 8 & JAMS-22 - 巻頁： 94 - 97 2020年

New procedure of CO2 extraction for radiocarbon analysis of DIC in water samples at Nagoya University and Geological Survey of Japan. 国際共著

南雅代

Proceedings of EA-AMS 8 & JAMS-22 - 巻頁： 60 - 63 2020年

イラン北西部アリ・サドル洞窟のつらら石のU/Th年代, 14C年代, 炭素・酸素安定同位体比

堀川恵司, 南雅代, 安間了

都市文明の本質：古代西アジアにおける都市の発生と変容の学際研究研究成果報告2019年度 1 巻頁： 187 - 195 2020年

A SUITABLE PROCEDURE FOR PREPARING OF WATER SAMPLES USED IN RADIOCARBON INTERCOMPARISON 査読有り

Takahashi H. A., Minami M., Aramaki T., Handa H., Saito-Kokubu Y., Itoh S., Kumamoto Y.

RADIOCARBON 61 巻 ( 6 ) 頁： 1879 - 1887 2019年12月

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

Web of Science

Scopus

RADIOCARBON DATING OF TEXTILE COMPONENTS FROM HISTORICAL SILK COSTUMES AND OTHER CLOTH PRODUCTS IN THE RYUKYU ISLANDS, JAPAN

Nakamura Toshio, Terada Takako, Ueki Chikako, Minami Masayo

RADIOCARBON 61 巻 ( 6 ) 頁： 1663 - 1674 2019年12月

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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Scopus

EFFECT OF CRYSTALLINITY OF APATITE IN CREMATED BONE ON CARBON EXCHANGES DURING BURIAL AND RELIABILITY OF RADIOCARBON DATING

Minami M., Mukumoto H., Wakaki S., Nakamura T.

RADIOCARBON 61 巻 ( 6 ) 頁： 1823 - 1834 2019年12月

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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Radiocarbon changes of unpoisoned water samples during long-term storage 査読有り

Takahashi Hiroshi A., Minami Masayo, Aramaki Takafumi, Handa Hiroko, Matsushita Makoto

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS 455 巻頁： 195 - 200 2019年9月

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

Web of Science

Scopus

多段階の堆積サイクルを経た堆積物・堆積岩における源岩の初期Sr同位体比の保持―淡路島の細粒河川堆積物を例に― 査読有り

太田充恒, 南雅代

地球化学 53 巻 ( 2 ) 頁： 59 - 70 2019年6月

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

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.

DOI： 10.14934/chikyukagaku.53.59

CiNii Research

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