塔里木东北缘第四纪地质环境演化研究

On the Quaternary Environment Evolution in the Northeast Margin of Tarim

罗布泊地区是我国西北干旱区环境研究的热点,在罗布泊干湖周边,保留有丰富的地质环境信息。为此,在罗布泊西北缘,针对区域地层构造分布特征、构造活动事件序列、湖泊沉积物及堆积土层中的环境信息进行分析,定量/半定量地重建了第四纪环境和气候变化,解析了未来可能再度出现的地质环境和气候变化的可能性。研究表明:本区第四纪以来主要有767~531 ka、255~158 ka和43~34 ka 3次较大规模构造活动,影响了罗布泊干湖近代的地形地貌分布特征,也影响湖面变化;研究区所处基岩剥蚀台地,地貌由剥蚀准平原化向平原化演化,通过基岩剥蚀"夷平"雏形时间和周边石质文物估算,剥蚀率为0.09~1.2 mm·ka^(-1)。总体上,该区域的干旱化趋势仍会持续。

Lop Nor area is a research hotspot of arid region because of the abundant geological environment information in the strata around Lop Nor dry lake. According to regional stratigraphic and tectonic information,sequence of tectonic events,the environmental information of lake sediment,the study reconstructed the quaternary environment and climate change quantitatively or semi quantitatively and estimated the trend of geological environment and climate change in the future. The study showed that,three large-scale tectonic activities which in 767-531 ka,255-158 ka and 43-34 ka（ middle-late stage of late pleistocene） influenced the modern topography distribution feature,and the ancient lake location changed since the quaternary period. This area is sated erosion platform,and has relatively stable development history,the erosion rate is about 0. 09-1. 2 mm·ka-1through the bedrock erosion ＂flattened＂time and surrounding stone relics denudation rate. Through the above quaternary geological environment evolution and climate change exploration in northwestern margin of the LBP,we conclude preliminarily the tectonic activities control the hydrological distribution of study area,especially the scope of the ancient lake. In general,the climate of Lop Nor area for acidification is likely to continue.