Abstract
The Last Glacial Maximum (LGM) is a key reference point for understanding past climate, but its complexity can lead to ambiguities in scope and interpretation. In this study, we applied a suite of geochemical techniques -XRF, grain size, and pollen analysis- to a well-dated sedimentary sequence from the lower central plain of Thailand. Our results show a gradual increase in fluvial runoff and precipitation from 26.5 to 24.6 cal ka BP, followed by reduced discharge around 24.6–24.1 cal ka BP, correlating with Heinrich event 2. A subsequent decline in runoff until 23 cal ka BP was followed by a distinct increased precipitation between 23–22.8 cal ka BP, with an abrupt shift to drier conditions post 22.8 cal ka BP. Comparing our records with other paleo records from the Sundaland imply that the Intertropical Convergence Zone (ITCZ) did not shift significantly north during the LGM. Instead, we suggest an ENSO-like phenomenon modulated tropical rainfall during the LGM as a result of the exposed Sunda Shelf, which enhanced precipitation and created a climate similar to the present tropical wet-dry or savanna climate, with pronounced seasonality. Our results highlight the complexities associated with tropical climate variability, challenging the conventional uniformity of cool and dry conditions during the LGM.