Monsoon rainfall and contrasting source rocks influenced sediment composition of peninsular basins along the east coast of India (western Bay of Bengal)
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Date
2020Author
Peketi, A.
Mazumdar, A.
Pillutla, S.P.K.
Rai, V.K.
Sawant, B.
Chaitanya, A.V.S.
Krishna, R.
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The peninsular India is characterized by remarkable variation in lithological composition as well as contrasting rainfall distribution patterns. The erosional and weathering history of these source rocks along with monsoonal changes are archived in sediments deposited in the basins along the east of coast of India. Here, we present a 60 ky record of Sr-Nd isotope ratios coupled with major elemental compositions of a sediment core off Krishna-Godavari (K-G) basin, western Bay of Bengal. The marked temporal variation in 87Sr/86Sr, epsilon Nd, and Mg/Al ratios are attributed to the changes in relative contribution of sediments from the Deccan Basalts (DcB) and Archean-Proterozoic gneissic complexes (APGC). The enhanced contribution of APGC associated with an increase in monsoon precipitation may be attributed to heightened erosion of the granitic gneissic rocks. On the other hand, a close correlation of 87Sr/86Sr ratios with Rb/Sr ratio, delta18OG-ruber, and CIA profiles indicate the possible influence of weathering intensity on the sediment composition.
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