Fluvial response to Late Quaternary climate changes, western India

Abstract

We review here the fluvial response to Late Quaternary climatic changes in the semi-arid regions of western India, i.e. the Thar Desert and its margins, and Maharashtra. The rivers in the Thar Desert show a spectrum of environments from gravel bedload braided to ephemeral sand-bed streams to sheet flows and sheet floods, while those in the Thar margin and Maharashtra show dominantly two modes, i.e. braided and meandering rivers. The streams became defunct and aeolian sands were deposited during periods of relatively greater aridity in the Thar Desert and its margins. Incisions occurred during the wet phases in OIS 1. It is inferred that changes in the monsoon precipitation led to relative changes in the discharge and sediment supply, which were routed through those in the vegetation cover, and played a key role in determining the fluvial style. An inter-comparison of the Late Quaternary alluvial deposits in the semi-arid regions of western India suggests a continuum of fluvial environments interrelated through a precipitation gradient. Further, a global comparison indicates that the response of semi-arid western Indian rivers was synchronous with the rivers in other climatic settings.