HOLOCENE PALEOENVIRONMENTAL EVOLUTION OF THE HUGUANGYAN MAAR LAKE

LOI 550℃(loss on ignition at 550℃) and Ti、Al、Si、K intensities of the sediments from the Huguangyan Maar Lake were analyzed for reconstruction of the Holocene paleoenvironmental evolution.. LOI mainly reflects the production changes within the drainage basin, whereas Ti、Al、Si、K mainly depend upon the runoff input of the drainage basin. During the period of 11 000~7 800 cal.aBP, the climate at the Huguangyan district was warm and wet. After 7 800 cal.aBP, it quickly became dry and cold. Though there were a series of climatic fluctuations since 7 800 cal.aBP, they were much weaker than those in the early Holocene. Millennial-scale Holocene paleoenvironmental evolution recorded by the sediments of the Huguangyan Maar Lake is consistent with other records in the Asia monsoon area:the climate was optimum in early Holocene, and became relatively colder and drier since the Mid-Holocene. The Mid-Holocene temperature falling reflected by the Huguangyan Maar Lake sediment was much bigger than that from other records in the Asia monsoon area, due to the differentiation of Holocene climatic evolution in different geographical locations. The Mid-late Holocene climatic evolution in the Huguangyan district may have some relationship with the El Niño system.