石筍指示之一萬六千五百年來東帝汶溫度及降雨變遷

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 replicated stalagmite calcite δ18O records over past 16.5 thousand years (ka, before 1950 AD) from Lekiraka cave in East Timor (8⁰47’10.8”S, 126⁰23’31.1”E; 626 m above sea level) are presented. Integrated with speleothem inclusion water oxygen and hydrogen isotopic measurement, thermal and hydrological dynamics since the last glacial time are revealed. Paleo-cave temperature inferred from coupled stalagmite δ18O of carbonate and coeval inclusion water started increasing during Heinrich event I, was similar to increment of global temperature change. The temperature record follows local summer insolation curve since the early Holocene, however, contradicts to sea surface temperature (SST) records. The results suggest that the SST was mainly affected by IPWP expansion associated with Northern hemisphere (NH) summer insolation, but air temperature in East Timor was governed by 10°S insolation. Inclusion water oxygen and hydrogen isotopic data show different seasonal moisture sources between the Holocene and glacial time, suggesting that glacial-interglacial sea-level change of Sunda shelf landmass may lead to alteration of the regional atmospheric circulation and hydroclimate.