ABSTRACT
A 5.1 m sediment core extracted from Pottuvil lagoon in southeast coastal lowlands of Sri Lanka was used to trace the temporal variability of As enrichment in coastal sediments in response to dynamic monsoon climate throughout the Holocene. Geochemical study along with AMS 14C dating and Bacon Age Depth modeling suggested that As enrichment in lagoon sediments is favored by strong monsoon activity phases and As depletion is occurred during weak monsoon periods. Most interestingly, As accumulation declined during 5.2 and 4.2 Ka Bond events in response with the abrupt weakening of monsoon climate. This study reveals that As enrichment in Holocene sediments of Southeastern Sri Lanka is significantly affected by changing tropical monsoon climate over past 6000 yrs BP in millennial and centennial time scale. Chronology of major climate shifts detected in Pottuvil proxy record is comparable with regional records from Indian monsoon regime.
