An environmental magnetic record of Holocene climatic variability from the Chilika Lagoon, Southern Mahanadi Delta, east coast of India

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 (rlf, rhf, rARM 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 (rlf) 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.