第六届青年地学论坛

1463 / 2019-08-10 19:05:00

Holocene high-resolution Indian Ocean Monsoon record in the Andaman Sea

6、海洋地球科学 > 专题8：热带海洋多尺度气候变化及其对全球气候的响应和影响

Although many researches have been conducted on marine sediment to reconstruct the evolution of Indian Ocean Monsoon (IOM), it is still hard for us to understand the changes of the IOM precipitation and evaluate the linkage between terrestrial and ocean hydroclimate during the Holocene, largely due to the lack of the high-resolution marine record in Indian Ocean. Here we present a high-resolution, well-dated reconstructions of sea surface temperature (SST) and local δ18Osw by planktonic foraminifera Globigerinoides ruber sensu stricto (s. s.) in the Andaman Sea. Local δ18Osw value is the minimum at 10.6-8.6 ka BP, indicating the lowest SSS and the maximum monsoon precipitation, and its SST is relative low. From 8.6 to 5.0 ka BP, local δ18Osw values increase a lot, inferring the increase of SSS and the decline of IOM precipitation. After 5.0 ka BP, local δ18Osw become more positive, suggesting further increase of SSS and the decrease of IOM precipitation. SST reaches the highest at 8.6-3.6 ka BP, but it declines slightly after 3.6 ka BP. Our results also reveal that there are many clear centennial-scale variations on SST and IOM precipitation during the Holocene. The evolution of IOM precipitation recorded by our local δ18Osw is coherent with stalagmite δ18O in southern Oman and Southwest China during the Holocene, which is perhaps controlled by summer solar radiation, but SST is affected by both summer solar insolation and monsoonal precipitation.