Reconstructing Late Quaternary Palaeo‐environmental change from the dryland fluvial landscape of the Southern Kachchh Mainland, western India: Insights from new OSL and sedimentological datasets

Abstract

The southern Kachchh Mainland (SKM) of western India, situated in a seismically active intraplate region with a considerable Quaternary landscape, provides an opportunity to reconstruct the roles of climate and tectonics. Employing geomorphology, detailed sedimentology supported by geochemistry and optical dating, we integrate the fluvial to fluvio‐marine records to evaluate the potential of dryland environments in archiving the palaeo‐events. The climate reconstructions suggest that the fluvial systems have responded to the variations in monsoonal strength through widespread aggradation during 57 until 41 ka, corresponding to the later part of the MIS‐3. Following this, a relative weakening of monsoon and onset of aridity is observed between 28 and 11 ka, with short spells of enhanced monsoon. The monsoonal conditions again strengthened during 11 to 6 ka, reaching its maximum during the Early Holocene optima, which triggered a sea‐level rise during the Middle Holocene period, that is, 6 to 3 ka. Following this, the sequences incised in response to the relative sea‐level fall to the present level in post 3 ka. We have also employed this OSL ages to reconstruct the phases of aggradation and incision of valley fill sediments/estuarine tidal terraces from the SKM during the last 57 ka. The present study illustrates and contributes to the advancement in understanding of complex processes and their influence on climatic/tectonic signals in dryland landscape as well as their decoupling.