Seminar

Holocene climate change in mid-latitude Asia, which is controlled by Asian summer monsoon and the westerlies at present, is still not fully understood. Recent studies have shown a dramatic climate change in this region at around 4 ka; however, whether it marks a cold period or is due to intensified monsoon is controversial. In this project, Holocene temperature and moisture changes are proposed to study using long-chain alkenones as biomarkers from Lake Sayram, which is a deep water lake at northwestern China. Preliminary results show a generally cooling and wetting trend through the Holocene. Superimposed on this long term trend is an exceptional warm and dry period at mid-late Holocene, confirming the change at around 4 ka to be a warm event.