Tachambalath, A.P.; France-Lanord, C.; Galy, A.; Rigaudier, T.; Charreau, J.
Proceedings of the International Ocean Discovery Program, 2023, 354
Voir en ligne : https://doi.org/10.14379/iodp.proc.354.204.2023
Abstract :
During International Ocean Discovery Program Expedition 354, seven sites were drilled along a 320 km east–west transect at 8°N, constituting a relic of the Neogene sediment record of Himalayan erosion. Bengal Fan is one of the largest deep-sea fans in the world where turbiditic sediments issued from the Ganga and Brahmaputra River Delta and originally supplied by the Himalayan erosion of silicate and carbonate lithologies are deposited and stored. Quantification of
the chemical composition of silicates and carbonates is necessary to understand the tectonoclimatic history of this region. This report presents the major and trace element concentrations of silicate and carbonate fractions of selected turbiditic samples from Sites U1450 and U1451. Efficient washing followed by refined acid leaching of the sediments was performed to eliminate sea salts and carbonates from these marine sediment samples. Shipboard samples show 20%–40%
excess sodium concentration associated with sea salt derived from pore water. Weak acid treatment limits the total carbonate content in the samples to less than 0.1%. Depletion of major and trace elements observed due to acid leaching is attributed to the dissolution of carbonates and cations associated with Fe-Mn oxyhydroxides.