Journal Articles Geochimica et Cosmochimica Acta Year : 1994

δ13C of organic carbon in the Bengal Fan: Source evolution and transport of C3 and C4 plant carbon to marine sediments

Abstract

Carbon isotopic measurements on organic carbon in sediment cores from the Bengal Fan (ODP Leg 116) show a dramatic 10 ‰ increase beginning ca. 7 Ma ago, and a rapid decrease after 0.9 Ma. These shifts reflect changes in the mixing ratio of terrigineous carbon derived from C3 and C4 plants. The rapid increase in δ 13 C of Bengal Fan OC at 7 Ma show that C4 expansion already documented in the Siwaliks was widespread overall the Himalayan foreland. After 7 Ma, relations of δ 13 C with sedimentological parameters show that C4 plants dominates in the foreland whereas C3 plants remain in the mountain range. Variations in the source of the sediments and of the OC appear to be sensitive to climatehydrologic conditions in the basin. Major changes in the isotopic composition of the carbon flux in one of the largest river system modify the isotopic budgets of both marine dissolved carbon and the sedimentary carbon mass.
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hal-03408720 , version 1 (29-10-2021)

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Christian France-Lanord, Louis A Derry. δ13C of organic carbon in the Bengal Fan: Source evolution and transport of C3 and C4 plant carbon to marine sediments. Geochimica et Cosmochimica Acta, 1994, 58 (21), pp.4809 - 4814. ⟨10.1016/0016-7037(94)90210-0⟩. ⟨hal-03408720⟩
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