中文摘要：

桂林地区曾是古人类活动活跃的地区，据可以断代的古人类洞穴遗址统计，发现桂北地区大部分的洞穴遗址其年代的下限都在距今约7000a左右，此后古人类离开了洞穴，史前文化也随之发生了重要改变。影响古人类演化的因素有很多，究竟是什么原因驱使古人类离开洞穴，改变生活习性，这一问题一直都是困扰考古学界的难题。本文通过研究桂北地区洞穴遗址的堆积特点，结合洞穴沉积-堆积物的特征及其孢粉记录的古气候信息，探讨了季风气候变化对桂林地区古气候变化的影响作用和气候演变历史，揭示了桂林地区全新世以来的季风气候变化时间序列和突变事件以及对古人类生存环境的影响。距今7000a左右为中全新世气候适宜期，东亚夏季风强盛，气温升高，桂林地区的降雨增多，一方面由于地下河水位升高，淹没了穴居洞穴，其次是由于降雨增多，导致洞穴湿度增大，从而迫使古人类搬出洞穴。

英文摘要：

Guilin was an area of human activity in ancient time. Statistics of paleoanthropologic cave relics show that the upper limit of the human activity can be traced hack to 7000 a B P in northern Guilin. After that, primitive men left caves, and their prehistoric culture also changed. What drove primitive men to leave caves and change their customs？ This is a problem that has long puzzled archaeologists. This paper has studied characteristics of the cave relics and paleoclimatic records of speleothem and pollen and discussed changes of paleoclimate driven by monsoon. On such a basis, a conclusion is drawn that living conditions of the primitive men might have been disturbed by some abrupt events and the changing time sequence of the nonsoon since Holocene. About 7 000 years ago, the primitive men were forced to leave the caves. The reason is as follows： At that time, there existed an optimal period of Middle Holocene and the climate of southeast China was mostly affected by the summer east monsoon, and the rainfall in Guilin area increased, which led to the elevation of the water level of underground rivers and the flooding of the caves.