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Title Transcription
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
Title Alternative (English)
Late Early to early Middle Triassic bedded cherts in the Tanba Belt and black organic mudstones in the P/T boundary, Southwest Japan
File
language
jpn
Author
Yamashita, Masayuki
Ishida, Koutaro
Description
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.
Journal Title
Geological reports of Shimane University
Volume
11
Start Page
87
End Page
96
ISSN
0287816X
Published Date
1992-07-30
NCID
AN00054980
Publisher
島根大学理学部地質学教室
Publisher Aalternative
Department of Geology, Faculty of Science, Shimane University
NII Type
Departmental Bulletin Paper
OAI-PMH Set
Faculty of Science and Engineering
Remark
1-11 / 1982-1992
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