黄河上游玛曲地区晚全新世沙漠化

A STUDY ON DESERTIFICATION SINCE LATE HOLOCENE IN MAQU AREA,UPSTREAM OF HUANGHE RIVER

本文通过野外调查和样品室内分析，探讨了玛曲地区沙漠化过程。结果表明，该区晚全新世以来的沙漠化与全球变化具有一致性，沙漠化的发生发展受控于全球变化。据￣（１４）Ｃ测年，沙漠化主要经历２６００—１９００ａＢ．Ｐ．，１９９０—７５０ａＢ．Ｐ．，７５０—２２０ａＢ．Ｐ．和２２０ａＢ．Ｐ．至今四个阶段，而２２０ａＢ．Ｐ．以来的现代沙漠化是自然因素与人为作用迭加的结果。

In Maqu area,the mian cause of desertification lies in the Climatic changes.According tofield work and ￣(14)C dating,the desertification in the area experienced four perieds,namely 2 600-1900 aB.P.,1900 750aB. P. ,750-220aB.P.and 220 a B.P.to teday.Only in the periodfrom 220 a B. P. up to now,the desertification process was influenced by both the climatic changesand human activities.The desertification processes are consistent with Chinese climatic chamges and thedesertification processes in Genghe basin. With prolonged deflation some stcady minerals areaccumulated and sand well sorted,although the eolian sand mainly comes from the depeits of HuangheRiver.