Stalagmite-inferred precipitation and temperature dynamics in East Timor over the past 16.5 thousand years

Abstract:

Located in the Indo-Pacific Warm Pool (IPWP), the largest warm water mass in the world, Australian-Indonesian monsoon is one of the most important global climate systems. Here we present replicated stalagmite calcite d¹⁸O records over past 16.5 thousand years (ka, before 1950 AD) from Lekiraka cave in East Timor (8^o47’10.8”S, 126^o23’31.1”E; 626 m above sea level). Combined with speleothem inclusion water oxygen and hydrogen isotopic measurement, thermal and hydrological dynamics since the last glacial time are revealed. Data inferred from coupled stalagmite d¹⁸O records of coeval inclusion water and carbonate indicate that there is no significant cave temperature difference during deglaciation. Stalagmite calcite d¹⁸O time series shows a relatively dry condition during the glacial period, comparing with the Holocene. Different relationship between inclusion water oxygen and hydrogen isotopic data reveals clearly various seasonal moisture sources between the Holocene and glacial time. The glacial-interglacial change of Sunda shelf landmass profoundly leads to alteration of the regional atmospheric circulation and hydroclimate.