RECORD OF PALEOENVIRONMENTAL CHANGES IN PINGDINGCUN SECTION, HEBEI PROVINCE

From field observation, sporopollen analysis and ¹⁴C dating of samples collected from the Pingdingcun Section, Hebei province, the sediments involved are determined to have formed from Late Pleistocene to Early Holocene.According to an estimate of the temperature then prevailing by Fe³⁺/Fe²⁺ ratio and an analysis of the change of CaCO₃ content, the paleoclimate of the Yangyuan area has obviously experienced four stages in the period, i.e. warm-humid, cold-dry, cold-humid and warm-dry stages.The sporopollen assemblages reflect that a change in vegetation from forest to grass land has occurred.