QUATERNARY ENVIRONMENT CHARACTERISTICS IN THE SOUTHERN MARGIN OF SONG-LIAO BASIN: A case study of Siping-Suangliao area

The Siping-Shuangliao area, situated in the overlapping zone of agriculture and livestock husbandry in North China, is one of the sensitive regions to global paleoenvironmental changes during Quaternary. With discussion on the sporopollen characteristics, ecologic background, paleoclimate and environmental changes, three kinds of ecologic background, i. e. forest-steppe, veld and grassland, are recognized on the basis of sporopollen characteristics. The climate and environment have periodically changed since Quaternary. The Quaternary ecologic environment on the southern margin of Song-Liao basin Ires undergone a process with three times of sandy ground expansion and twice contraction. The modern ecologic changes are caused by both natural and artificial factors.