塔里木盆地南缘历史时期气候环境变化的过程与特征

根据塔里木盆地南缘具较高分辨率的湖沼相沉积物碳酸盐δ^13C和粒度等记录，恢复出2162-850BC期间为一相对稳定的温暖干旱时期，之后迅速转冷湿，湿润程度呈持续、阶段式增加，50 BC至500 AD期间呈现的显著冷湿特征于550 AD之后突变转暖干而结束。550 AD和1000 AD前后的具突变性质的气候事件在南疆地区近2．0ka的气候变化中具有重要意义，反映气候状况有过重大调整。850—1300AD期间(相当于中世纪温暖期)冷暖、干湿多变，但温暖特征并不明显。特别是1100—1200AD期间气候快速、频繁变化之后，奠定了本地区现代稳定干旱环境特征。区域对比表明，尼雅剖面记录的气候变化具有广泛的区域一致性。

Process and Characteristics of Historical Climate and Environment Changes in Southern Margin of Tarim Basin

Based on the high-resolution multi-proxies of climatic changes recorded in lacustrine sediments of the Niya section in the south margin of Tarim basin, the history of climate change has been reconstructed. During 2163_850 BC, the climate was characterized by relatively stable warm-dry conditions, afterwards it turned into a relatively cold-wet period and the cold-wet intensity consecutively increased phase by phase. An evident cold-wet period lasted from 50 BC to 500 AD and ended at about 550 AD. The abrupt climate events happened at about 550 AD and 1000 AD are of very important significance in climate changes of southern Xinjiang during the last 2^0 ka, which indicated that the climate was ever re-arranged greatly. During 850_1300 AD, corresponding to the Mediaeval Warm Period, the climate was dominated by alternation between cold-warm and wet-dry, but with not apparent warming characteristic. Especially during 1100_1200 AD, the stable warm-dry environment of this region was established after a series of climate change rapidly and frequently. Spectrum analysis has throw light on several evident climatic cycles of about 60 a, 15 a, 11 a recorded in the Niya section, which indicated that climate change in this area was possibly affected by solar forcing, and regional comparison shows that climate change during the past 4^0 ka recorded in Niya section has regional consistency.