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タイトルヨミ
タンバタイ ニ ミラレル トリアスキ コセイ チュウセイ ソウジョウ チャート ト P T キョウカイ ノ コクショク ユウキシツ デイガン
日本語以外のタイトル
Late Early to early Middle Triassic bedded cherts in the Tanba Belt and black organic mudstones in the P/T boundary, Southwest Japan
ファイル
言語
日本語
著者
山下 雅之
石田 耕太郎
内容記述(抄録等)
Lithologic characteristics, biostratigraphy and geochemical analysis of the late Early to early Middle Triassic bedded cherts were described from the two locations, Ashimi section in Type I (T I) suite and Taki section in Type II (T II) suite of the Tanba Belt, Southwest Japan, and the sedimentary environments of siliceous rocks in eath suite is evaluated.
Bedded cherts in Ashimi section are composed of altemating beds of black to dark gray siliceous parts and dark gray to yellowish gray clay parts, and characteristically contain intercalated organic black mudstones. In two horizons in this section yielded the Spathian to Anisian conodont, Neopathodus homeri (Bender) . In contrast, bedded cherts in the Taki section producing the late Spathian radiolarians, Parontactinia sp. characteristically occurred from red cherts and shale partings. Moreover, some of the late Early to early Middle Triassic bedded cherts in T II unit also indicate the same color variation.
Lithologic feature described above suggests that the paleo-oceanic basins under the varied sedimentary environments (ex. oxic/anoxic environments) had occurred in the late Early to early Middle Triassic, and T I and T II units are representative of mutually different paleo-oceanic basins. This indicates that an anoxic sedimentary environment throughout P/T boundary had changed to oxic environment in oceanic basin of T II unit at the earlier stage than that of T I unit.
掲載誌名
島根大学地質学研究報告
11
開始ページ
87
終了ページ
96
ISSN
0287816X
発行日
1992-07-30
NCID
AN00054980
出版者
島根大学理学部地質学教室
出版者別表記
Department of Geology, Faculty of Science, Shimane University
資料タイプ
紀要論文
部局
総合理工学部
備考
1-11 / 1982-1992
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