Abstract: The Dongfang Plaza cultural site, located in Wangfujing, Beijing, is the first found of late paleolithic relic in Beijing plain. The process of climate change during 26-14ka B.P. will be discussed in this paper, based on the analysis of the sedimentary facies characters and paleo-environment indexes such as clay mineral, chemical element and spore-pollen of the sediment samples collected from the middle-part of the stratigraphic profile (including upper and lower cultural layers) of the Dongfang Plaza cultural site. The landform on which ancient human activity relic located was interfluvial floodplain on Yongding River Alluvial Fan. The result of analysis shows that the climate of the period during which these strata were formed was mainly dry and cold, and the pollen of herbs is predominant. In the later part of this period the temperature and humidity increased a little, especially between the two cultural layers there was a short but clear section of wet and warm climate and a temperate forest steppe landscape existed. So it can be concluded that after the lower cultural stratum was formed, the flood became greater due to the wetter weather and bigger river discharge, and the ancient people were forced to move to other higher places. Later the climate began to dry and human activities appeared here again. In such a way two cultural strata were formed. Cultural sites of dry-cold late Late-Pleistocene have been found in Beijing, Inner Mongolia Autonomous Region, Heilongjiang province and other places, which indicates that the people of late Late-Pleistocene already had the ability to defend the dry-cold weather.

Key words: The Dongfang Plaza cultural site, clay mineral analysis, chemical element analysis, spore-pollen analysis, ancient human activity

摘要： 北京王府井东方广场旧石器时代晚期人类活动遗址，是在北京平原的首次发现。依据对遗址区剖面中段(包含了上下两个文化层)沉积样品的沉积相特征以及粘土矿物、化学元素和孢粉等古环境指标的分析，探讨了2.6万年前后至1.4万年前后古环境的演变过程。古人类活动遗址所处地貌部位为古永定河冲积扇的河间冲积平原。古环境分析表明，文化层出现前后的这一段时期，一直以干冷气候为主，草本花粉占绝对优势，中后期温湿度有所增加，尤其上下文化层之间曾有一个短暂而明显的较为温湿的时期，出现了温带森林草原景观。在下文化层形成之后，由于气候转湿，河流水量增加，洪泛加剧，古人类活动范围有可能限于其他地势较高的地区，后期气候又有所变干，古人类活动才又涉足本区，因而形成上下两个文化层。晚更新世晚期干冷气候背景下，古人类活动遗址在北京、内蒙和黑龙江等地的发现表明，当时的古人类已具有能抵御干冷气候的能力。

关键词: 东方广场遗址, 粘土矿物分析, 化学元素分析, 孢粉分析, 古人类活动