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Title Transcription
セイナン ニホン ノ チュウブ ペルムケイ ソウジョウ チャート ニ キロク サレタ タイセキ サイクル ト コリュウコウ ノ カイセキ
Title Alternative
Depositional Cycles and Paleocurrent in Pelagic Condition from Example of Middle Permian Bedded Cherts, Southwest Japan
File
language
eng
Author
Imoto, Nobuhiro
Description
Depostional cycles of the Middle Permian bedded chert sequence are examined in view point of lithology, composition and mode of occurrence of microfossils. Cyclic compositional change was veryfied by alternating occurrence of two distinct type of chert beds which are one biogenic called siltite, and the other fine siliceous ones called lutite. Thickness of beds forms cyclic peaks and of which composition of alternatively change between siltites and lutites. This points change of radiolarian blooming and deposition are intimately related to that in low-stand in sea level when activated circulation on botton surface was dominated, while in high-stand in sea level slow flux of coarse siliceous materials with varied biomass fertilized conodonts. These two oceanic conditions were clearly recorded in the lower to middle Middle Permian but it gradually became unclear in upper Middle Permian, prior to Upper Permian regression. Prefered orientation of Follicucullus shell characterized by elongated conical shape indicates bottom currents were regular in direction almost through the Middle Permian and an asymmetry in arrangement of shell vertical to the supposed current alludes possibly inclined paleoslope of the depositional basin and current parallel to this slope.

Journal Title
Memoirs of the Faculty of Science, Shimane University
Volume
27
Start Page
65
End Page
72
ISSN
03879925
Published Date
1993-12-25
NCID
AN00108106
Publisher
島根大学理学部
Publisher Aalternative
The Faculty of Science, Shimane University
NII Type
Departmental Bulletin Paper
OAI-PMH Set
Faculty of Science and Engineering
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