Maar and crater lakes of the Long Gang Volcanic Field (NE China) -: overview, laminated sediments, and vegetation history of the last 900 years

Maar- and crater lakes have, due to their specific formation and characteristic morphology, a high potential for the development and preservation of seasonally laminated sediments (varves). Within the Long Gang Volcanic Field (LGVF) in N.E. China eight maar- or crater lakes with water depths between 15 and 127 m are located. The seasonal climate with strong influence of the East Asian summer- and winter monsoon and the position of the LGVF at the northern margin of the East Asian dust storm tracks make these lakes key archives for palaeoclimatic studies. In the course of a site Survey for a deep lake coring water samples and short sediment cores were investigated from all of these lakes. Detailed pollen investigations of the last 900 years from Lake Sihailongwan, an ideally bowl-shaped maar lake with 50 m water depth, revealed a very stable vegetation cover, except for the last 150 years which shows increasing anthropogenic influence. No evidence could be found in the pollen record for a climatic deterioration comparable to the European Little Ice Age. However, climatic variations can be revealed from high-resolution geochemical and sedimentological investigations on a decadal to annual scale. (C) 2004 Published by Elsevier Ltd.