气候变化领域集成服务门户(CCPortal): Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean

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DOI	10.1016/j.epsl.2020.116329
	Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean
	Pickering K.T.; Carter A.; Andò S.; Garzanti E.; Limonta M.; Vezzoli G.; Milliken K.L.
发表日期	2020
ISSN	0012821X
卷号	544
英文摘要	The Nicobar Fan and Bengal fans can be considered as the eastern and western parts, respectively, of the largest submarine-fan system in the world. This study presents the integrated results of petrographic and provenance studies from the Nicobar Fan and evaluates these in the context of controls on sedimentation. Both fans were predominantly supplied by Himalaya-derived material from the main tectono-stratigraphic sequences as well as the Gangdese arc. A lack of volcanic material in the Nicobar Fan rules out sources from the Sumatra magmatic arc. Overall, the petrographic data shows a progressive decrease in sedimentary detritus and corresponding increase of higher-grade metamorphic detritus up-section. Changes in sediment provenance and exhumation rates in the Himalaya are seen to track changes in sediment accumulation rates. High sediment accumulation rates in the Bengal Fan occurred at ∼13.5–8.3 Ma, and in the Nicobar Fan from ∼9.5–5 Ma. Both fans show peak accumulation rates at 9.5–8.3 Ma (but with the Nicobar Fan being about twice as high), and both record a sharp drop from ∼5.5–5.2 Ma, that coincided with a change in river drainage associated with the Brahmaputra River diverting west of the uplifting Shillong Plateau. At ∼5 Ma, the Nicobar Fan was supplied by an eastern drainage route that finally closed at ∼2 Ma, when sediment accumulation rates in the Nicobar Fan significantly decreased. Sediment provenance record these changes in routing whereby Bengal Fan deposits include granitoid sources from the Namche Barwa massif in the eastern syntaxis that are not seen in the Nicobar Fan, likely due to a more localised eastern drainage that included material from the Indo-Burman wedge. Prior to ∼3 Ma, source exhumation rates were rapid and constant and the short lag-time rules out significant intermediate storage and mixing. In terms of climate versus tectonic controls, tectonically driven changes in the river network have had most influence on fan sedimentation. © 2020
关键词	Bengal Fan Indian Ocean IODP Expedition 362 Nicobar Fan sediment provenance Sunda subduction zone
英文关键词	Digital storage; Rivers; Stratigraphy; Submarines; Accumulation rates; Brahmaputra River; Intermediate storage; Provenance studies; Sediment accumulation; Sediment provenance; Stratigraphic sequences; Volcanic materials; Sediments; depositional environment; detrital deposit; geoaccumulation; petrography; provenance; sediment transport; sedimentation; submarine fan; tectonic evolution; tectonic setting; Andamans and Nicobars; Bengal Fan; Indian Ocean; Nicobars
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202834
作者单位	Earth Sciences, University College London (UCL), London, WC1E 6BT, United Kingdom; Dept of Earth and Planetary Sciences, Birkbeck, University of London, Malet Street, Bloomsbury, London, WC1E 7HX, United Kingdom; Laboratory for Provenance Studies, Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, 210126, Italy; Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, 2305 Speedway Stop C1160, Austin, TX 78712-1692, United States
推荐引用方式 GB/T 7714	Pickering K.T.,Carter A.,Andò S.,et al. Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean[J],2020,544.
APA	Pickering K.T..,Carter A..,Andò S..,Garzanti E..,Limonta M..,...&Milliken K.L..(2020).Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean.Earth and Planetary Science Letters,544.
MLA	Pickering K.T.,et al."Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean".Earth and Planetary Science Letters 544(2020).