PALYNOLOGICAL RECORDS IN XIPU SECTION,YANGYUAN

Palynological records of Xipu section reveal the local vegetational and environmental history within the last 16000aBP. A very low total Spore-pollen concentration indicates a grassland vegetation and cold~dry climate at Ca. 16000~11000aBP interval; A number of tree pollen grains found at Ca. 11000~9000aBP might be explained as a result of expansion of forests somewhere around the Xipu. This change must have caused by climatic warming and wetting in this time interval;the vegetation was dominated by sparse sylvosteppe at Ca. 9000~4800aBP, correspongding to the increasing temperature and decreasing humidity;During the last 4800aBP, the vegetation have remained as the grassland,but the decreasing concentration of the pollen might mean a reduction of forests and worsening environment around Xipu.