doi:10.14379/iodp.pr.354.2015

International Ocean Discovery Program
Expedition 354 Preliminary Report

Bengal Fan

Neogene and late Paleogene record of Himalayan orogeny and climate: a transect across the Middle Bengal Fan¹

30 January–31 March 2015

Christian France-Lanord, Volkard Spiess, Adam Klaus, and the Expedition 354 Scientists

Published May 2015

Abstract

International Ocean Discovery Expedition 354 to 8°N in the Bay of Bengal drilled a seven site, 320 km long transect across the Bengal Fan. Three deep-penetration and an additional four shallow holes give a spatial overview of the primarily turbiditic depositional system that comprises the Bengal deep-sea fan. Sediments originate from Himalayan rivers, documenting terrestrial changes of Himalayan erosion and weathering, and are transported through a delta and shelf canyon, supplying turbidity currents loaded with a full spectrum of grain sizes. Mostly following transport channels, sediments deposit on and between levees while depocenters laterally shift over hundreds of kilometers on millennial timescales. During Expedition 354, these deposits were documented in space and time, and the recovered sediments have Himalayan mineralogical and geochemical signatures relevant for reconstructing time series of erosion, weathering, and changes in source regions, as well as impacts on the global carbon cycle. Miocene shifts in terrestrial vegetation, sediment budget, and style of sediment transport were tracked. Expedition 354 has extended the record of early fan deposition by 10 My into the late Oligocene.

¹France-Lanord, C., Spiess, V., Klaus, A., and the Expedition 354 Scientists, 2015. Bengal Fan: Neogene and late Paleogene record of Himalayan orogeny and climate: a transect across the Middle Bengal Fan. International Ocean Discovery Program Preliminary Report, 354. http://dx.doi.org/​10.14379/​iodp.pr.354.2015

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