西门错地区2000年来的花粉组合与古气候

POLLEN ASSEMBLAGE AND PALAEOCLIMATE DURING LAST 2000YEAR IN XIMENCUO REGION, QINGHAI

通过花粉分析，划分出４个花粉组合带，讨论了２０００年来西门错地区古气候变迁特点。研究表明，２０００年来，该区总体上处于偏冷湿的气候背景，但仍存在４次相对冷暖波动旋回。中世纪暖期，增温幅度较小；距今５００年来，该区进入小冰期，气候有逐渐变干的趋势。孢粉结果与敦德冰心氧同位素曲线比较对应，但变化不如其明显，一方面与高寒地区植被生长状况有关，另一方面与湖盆位置选择有关。

Based on pollen analysis of about 37 samples from a 1. 47m-deep core in Ximencuo lake,Qinghai Province,4 pollen assemblages were distinguished,reflecting the palaeoclimatic changes in the past 2000 years.Studies indicate that under the colder-wet climalic background,there,existed climatic oscilations of 4 relatively cold and warm cycles in this region.In Middle Age,the amplitude of temperature increase was lower than in other warm periods,and the climate became drier since 500 years ago.belonging to the 'Little Ice Age'.The pollen date in this paper can be well compared to that of the Dunde ice-core record,although not so obvious in climatic change,and the results are related not only to the growth condition of vegetation in the arctic-alpine areas,but also to the selecte lake position.