DOI: 10.1016/j.epsl.2020.116329
论文题名: Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean
作者: Pickering K.T. ; Carter A. ; Andò S. ; Garzanti E. ; Limonta M. ; Vezzoli G. ; Milliken K.L.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 544 语种: 英语
中文关键词: 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
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 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165212
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
Pickering K.T.,Carter A.,Andò S.,et al. Deciphering relationships between the Nicobar and Bengal submarine fans, Indian Ocean[J]. Earth and Planetary Science Letters,2020-01-01,544