Geochemical records of mudflat sediments from southern Saurashtra, Western India: implication in Holocene climate and global teleconnection

Abstract

The heat transfer from the low latitudes to high latitudes is responsible to maintain the earth’s climatic equilibrium. Thus, deciphering the possible mechanism driving the Indian summer monsoon (ISM) variability during the Holocene Epoch, has been critical to understand the hydroclimatic changes of the low latitudes. Despite several efforts the teleconnection of ISM with the global climate dynamics remains under-represented and poorly understood. The present study aims to delineate the ISM
variability and its possible forcing mechanism from the western India (Gujarat) which is predominantly influenced by ISM rainfall. Here, a sediment core (~65 cm length) was raised from the Jaffrabad mudflat (MIT), western Gujarat and a geochemical investigation was conducted to decipher paleomonsoon, paleo-sediment source and paleoweathering changes. The study demonstrated that the sediments were primarily
derivatives of the Deccan basalts from the hinterland with an additional contribution of intermediate sources. Further, the study suggested a warm and wet climate due to ISM strengthening during 10650-5500 cal yr BP associated with the solar as well as orbital forcings. The weak monsoon during 5500-2700 cal yr BP has been linked with comparative migration of the Intertropical convergence zone (ITCZ) southward along
with the increased El Nino like conditions. Further, the wavelet analysis revealed that a combined influence of solar, orbital and North Atlantic forcings led to monsoon variability along the western India, during the Holocene epoch. By reconciling the geochemical proxies, the present study has implications in the reconstruction of paleomonsoon and establishing the possible teleconnection with the global climate system.