发生在大约4200年前的一场持续干旱可能是当时史前文明快速衰落的重要推手,这在全球许多区域均有记录,但在中国西北干旱区是否存在该事件依然缺乏有力证据。本文通过分析托勒库勒湖沉积地层的孢粉,发现新疆地区也存在类似4.2 ka BP气候事件的记录。4.5—3.8 cal ka BP期间的孢粉谱与前后时段相比有显著差异,禾本科和蒿属花粉含量快速降低、藜科急剧增加、A/C值降低;区域环境短期内变得极为寒冷-干旱,先前的草原/荒漠草原演化为荒漠。对比也发现,尽管这一事件在不同研究点的开始和结束时间略有差异,但变化特征具有较好的一致性。目前,关于这次事件的驱动机制仍不清楚,还需在新疆及其他敏感区域开展更多古气候研究。 A prolonged drought that occurred about 4,200 years ago may be an important promoter of the rapid decline of prehistoric civilization at that time, which is recorded in many regions of the world. However, there is still no strong evidence of the existence of this event in the arid northwestern part of China. In this paper, by analyzing the sporopollen in the stratum of Lake Tollekul, it is found that there is also a record of climate events similar to 4.2 ka BP in Xinjiang. The spore-pollen spectrum in 4.5-3.8 cal ka BP period was significantly different from that in the anteroposterior time period. The pollen content of Gramineae and Artemisia decreased rapidly, while that of Chenopodiaceae increased rapidly and the A / C value decreased. The regional environment became extremely cold in a short period of time, Drought, previous steppes / desert steppes evolved into deserts. The comparison also found that, although the event was slightly different at the beginning and end of different research sites, the change characteristics were in good agreement. At present, the driving mechanism for this incident is still not clear, and more ancient climate research needs to be carried out in Xinjiang and other sensitive areas.