Geochemistry and granulometry as indicators of paleoclimate, weathering, and provenance of sediments for the past 1,00,000 years in the eastern Arabian Sea

Abstract

Geochemical and granulometric investigation of a 408 cm long sediment core raised from the Eastern Arabian Sea was carried out to decipher the climate, weathering, dust flux and provenance of sediments during the past 100 ka. The diagnostic ratio of Cr/Ni (0.99 to 1.77), Rb/Al (6.01 to 17.14), Ti/Al (0.02 to 0.03), Fe/Al (0.94 to 1.61), Mg/Al (0.31 to 0.59) and silt% (38.68 to 66.37) indicate hot and humid climate with the intensification of south-west monsoon during marine isotope stage (MIS) 1, 3, 5a and 5c and cold and dry climate with the intensification of the northeast monsoon and high dust flux during Younger Dryas cooling, last glacial maximum, MIS 2, 4 and 5b. The clay% (20.42 to 53.92), Silica-Titanium Index (71.88 to 86.28), Ruxton Ratio (2.89 to 7.22), and Th/U ratio (0.98 to 4.11) indicate moderate to intense chemical weathering in the source area during warmer climate. Th(ppm) versus Sc(ppm), La/Th versus Th/Yb, Al2O3% versus Fe2O3%, Th/Sc versus Sc(ppm), La/Sc versus Sc/Th ratios and La-Th-Sc plot indicate intermediate/mixed sources for sediment provenance. Sand% (2.82 to 25.3), Si/Al (2.74 to 7.43), ?LREE/?HREE (7.65 to 10.40), La/Sc (2.24 to 3.55) indicate felsic sources from Peninsular India during warm climates and ?REE (103.98-201.17), Rb/Ga (1.36-4.33), Ni (70.42-137.3 ppm), Rb (55.39-138.90 ppm) indicate mafic sources from Deccan Traps and Arabian desert during cold climates. The synchronous relationship between the climate of lower and higher latitudes was observed, suggesting the global teleconnections of climate during the Late Quaternary