An environmental magnetic record of Holocene climatic variability from the Chilika Lagoon, Southern Mahanadi Delta, east coast of India. (1st June 2022) - Dash, Chinmay
Graphical abstract: Highlights: The Holocene experienced five major phases of climate variations. The Indian summer monsoon was stronger during the Early and Late Holocene. There was a prolonged phase of weak monsoon during the Mid-Holocene. Spectral analysis of χ lf data suggests solar influence on ISM rainfall. Abstract: Core sediments from the Chilika Lagoon in the eastern part of the Core Monsoon Zone (CMZ) of India have provided a record of local environmental changes and catchment processes during the past 7800 cal. years B.P. Variations in the rock magnetic parameters ( χ lf, χ hf, χ ARM and IRM's at varying field strengths) of sediment samples reflect climate-induced changes in the Chilika Lagoon catchment. The down-core variations in the concentration-dependent magnetic parameters indicate an intensified summer monsoon and enhanced terrigenous input to the lagoon during the Early to Mid-Holocene (∼7.8 ka to ∼ 5.5 ka B.P.). In contrast, the Mid- to Late Holocene period witnessed a weaker Indian Summer Monsoon Rainfall (ISMR) and less terrigenous input to the lagoon, with an intermediate phase of strengthened monsoon around 2 to 1 ka B.P. Spectral analysis of sedimentary magnetic susceptibility ( χ lf ) data show significant periodicities (at 95 % significance level) of 2523, 573, 147, 93, 59, and 55 years, which are in agreement with the periodicities shown by other paleoclimatic proxies from the region.