Temporal Changes in Land-Sea Configuration Inferred from Post-Glacial Sedimentation Pattern in the Western Great Rann of Kachchh, India

Abstract The sedimentology and geochemistry, supported by the published AMS radiocarbon and optical chronology of the sediment core raised from the Western Great Rann of Kachchh(WGRK), are used to reconstruct the pattern of post-glacial sedimentation. The study indicates that the hinterland fluvial system (viz. the Indus and the western Himalayan Rivers) was responsible for the sedimentation in the WGRK. The continental sediment fluxes were influenced by the post-glacial gradual strengthening of the Indian Summer Monsoon (ISM). During the latter part of the mid-Holocene, continental sediment flux was reduced due to the expansion of the marine transgression which persisted, albeit with hiatuses, until around 1ka. The geochemical analysis of major, trace and Rare Earth Elements points to a mixed sediment provenance that varied over time from the post-glacial period to the late Holocene. More specifically, it has been observed that the major contribution, invaried proportions, came from the upper Indus catchment and the Western Himalayan Rivers, with subordinate input of the fluvially reworked Aeolian sands. This study thus provides insight into the sedimentological evolution of one of the least studied Quaternary land forms in Western India, which is barely above the mean sea level and currently devoid of any active fluvial system. Keywords: Western Great Rann, Sedimentology, Geochemistry, Radiocarbon and Optical Chronology, Indian Summer Monsoon