新疆巴里坤湖400年来沉积地球化学特征及其古气候意义

GEOCHEMICAL CHARACTERISTICS AND SIGNIFICANCE OF LACUSTRINE DEPOSIT OF BALIKUN LAKE IN XINJIANG OVER 400 YEARS

本区干旱少雨,化学风化微弱。集水区内多数元素的迁移以碎屑形式、水的机械迁移为主,它们在最近400年湖积层中的相对富集或相对分散主要受区域气候干湿波动的影响,并完整记录了16世纪至18世纪早期相对冷湿、18世纪中叶到19世纪中叶相对暖干、19世纪中叶到20世纪六十年代相对温干以及七十年代相对凉湿的气候变迁序列。十九世纪以来,本区气候在波动中有偏凉偏湿的发展趋势,但二十世纪八十年代又趋向温干。

Balikun Lake is a closed lake basin in inland arid area of East Xinji- ang. Owing to rare precipitaton and weak chemical weathering,the elements migration is mainly mechanical in debris by surface runoff. Therefore, relative enrichment and dispersion of elements have mainly been influenced by dry and humid alternation of climate over 400 years, that is, the sequence of climatic variation has been completely recoded by the lacustrine deposits, i. e. relative cold-humid period from 16th century to early 18th century; relative hot-dry period from middle 18th century to the middle of the 19th century; relative warm-dry period from mid 19th century to 1960s; and relative cool-humid period since 1970s. Tendency of climatic variation in this area has fluctuately become cool and humid since 19th century, tending to warm-dry since 1980s.