Dianchi Lake Sediment Records of Climate Changes and Humane Activities in the Past 700 Years

Based on 210pb, 14C chronology and the measurements of mass susceptibility, δ13C, δ18O isotope, grain size, mineral component, calcium carbonate, and organic substances, the climate variation during the past 700 years in the area of Dianchi Lake has been established. It has distinct 200 a periodicity with two high and a low water level, Its climate is warm-dry and cold-wet alternated. The study also shows that the sediment has the information of humane activities. The depositional rate was changed by the dredging of Haikou River in Yuan dynasty. In recent decades, the contaminations of agriculture and industry were put into Dianchi Lake and changed the lakes nutrition, eutrophication gets accelerated.