Recent climate changes recorded by sediment grain sizes and isotopes in Erhai Lake

By careful sampling and accurate analysis of recent sediments, the time ser ies of sediment grain sizes and delta O-18, delta C-13 of carbonates in rec ent 700 years are successfully established, based on which the evolutionary history of the regional climate and environment in Erhai Lake is reconstru cted. The results show that the climatic succession type in the region of E rhai Lake is warm-dry and cold-humid alternatively, and there exist 200 and 400 years of quasi-periodical changes in temperature and 100, 200 and 400 years of quasi-periodical changes in aridity/humidity regime. The two colde st periods in recent 700 years occurred in the 14th century and the duratio n of 1550-1800 AD. The latter period may be the imprint left of the Little Ice Age.