罗布泊地区第四纪环境演化

新疆罗后干涸湖盆中的Ｋ１钻孔揭示，１００、２ｍ的沉积剖面共有９２个宙积层，划归１６同积旋回，包括了早更新世以来的各时期沉积。据划分的１５个孢粉组这及古地磁、１４＾Ｃ、岩石地层资料综合分析，早更新世该区曾发育森林－草原植被，早更民末，强烈的构造运动保留我下更充变形，上覆的中更统与下更新统间呈不整合接触。中更新世，荒漠和荒漠草原交替出现，地层中有大量膏质泥岩和石膏。晚更新世以来，在干旱气候的控制之下，

QUATERNARY ENVIRONMENTAL EVOLUTION OF THE LOP NUR REGION, NW CHINA

A drilling core, named K1, was taken from the bottom of the dried up lake of Lop Nur, situated at the east margin of the Tarim Basin. This core, about 100 m long, composed of mainly mud and sands with gypsum beds of early Pleistocene and younger, reveals an unconformity between the early Pleistocene and mid Pleistocene. Pollen analyses show clearly that in the early Pleistocene, the forest steppe vegetation was dominant in the region, but alternated to desert steppe and desert vegetations since the mid Pleistocene. The lake was developed probably as early as in the early Pleistocene. High percentage of Picea and total tree pollen suggests the existence of forests and comparatively wet condition near Lop Nur in the early Pleistocene. Arid environment started at the beginning of the mid Pleistocene and became extremely arid in the Holocene.