Palynological study on vegetation and climatic change in the subaqueous Changjiang (Yangtze River) delta, China, during the past about 1600 years

摘要

The well-defined pollen record in massive marine clay deposits from the subaqueous Changjiang (Yangtze River) delta reveals changes in vegetation and inferred climate during the last about 1600 years. Climatic periods inferred from the pollen record include (1) a basal cool/dry period (AD 385–910), (2) a relatively warm/wet conditions comparable to Medieval Warm Period (AD 910-1085) with a strengthen summer monsoon, (3) a relatively cool and wet conditions possibly corresponding to Little Ice Age (LIA; AD 1085–1815) with a weaken summer monsoon, and finally (4) the present warm period, since AD 1815. The pollen aridity index based on variations in humidity suggests that three subperiods within the LIA can be identified: wet LIA-1 (AD 1085-1170), dry LIA-2 (AD 1170–1330), and wet LIA-3 (AD 1330–1815).