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DOI	10.1130/B35483.1
	Neoproterozoic Blaini Formation of Lesser Himalaya, India: Fiction and Fact
	Dey S.; Dasgupta P.; Das K.; Matin A.
发表日期	2020
ISSN	167606
起始页码	2267
结束页码	2281
卷号	132 期号:2021-11-12
英文摘要	The long-conceived idea of the glacial origin of Blaini diamictite of Lesser Himalayan Neoproterozoic succession reached its maxima when the diamictites and capping pink limestone were attributed to the Neoproterozoic Snowball Earth event and its aftermath, respectively. Occurrences of diamictite-limestone association in two different levels have also been correlated with the Sturtian and Marinoan glaciations. Critical review, however, reveals that the interpretations of the glacial origin of diamictites are not well founded. The diamictite-limestone association, which occurs at the lower part of a thick, light brown shale unit and laterally grades into light brown shale, primarily indicates episodic surge events in an otherwise tranquil condition favorable for hemipelagic sedimentation. The lithology, bed geometry, internal organization, and disposition of the diamictite bodies suggest deposition of debris flow fan lobes along fault scarps in a rift setting. Emplacement of subaqueous debris flows is indicated by the associated deposits of entrained turbidity currents. The limestone also bears the signature of claciturbidites. The appearance of diamictite bodies and associated limestone in two distinct levels is not a stratigraphic disposition; on the contrary, the deposits were dislocated and repeated by two successive regional thrust faults. The Chemical Index of Alteration (CIA) values of the light brown shale and the matrix of the diamictites indicate that these sediments formed through prolonged subaerial weathering. The events leading up to development of the rift system and evidence of prolonged weathering within the basin-fill sediments are consistent with supercontinental break up, the prologue of Snowball Earth. © 2020 Geological Society of America. All rights reserved.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184715
作者单位	Department of Geology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India; Department of Geology, Durgapur Government College, Durgapur, 713214, India; Department of Earth and Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739–8526, Japan; Hiroshima Institute of Plate Convergence Region Research, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739–8526., Japan
推荐引用方式 GB/T 7714	Dey S.,Dasgupta P.,Das K.,et al. Neoproterozoic Blaini Formation of Lesser Himalaya, India: Fiction and Fact[J],2020,132(2021-11-12).
APA	Dey S.,Dasgupta P.,Das K.,&Matin A..(2020).Neoproterozoic Blaini Formation of Lesser Himalaya, India: Fiction and Fact.Bulletin of the Geological Society of America,132(2021-11-12).
MLA	Dey S.,et al."Neoproterozoic Blaini Formation of Lesser Himalaya, India: Fiction and Fact".Bulletin of the Geological Society of America 132.2021-11-12(2020).