新疆罗布泊环状盐壳的特征与成因

通过实地测量、物质成分分析和卫星像片判读,得出关于罗布泊东湖环状盐壳特征与成因的部分新结论:在东湖耳轮状区域内,地表物质组成以石盐为主,特别是氯化物占优势,碎屑矿物中主要为石英;“大耳朵”形态的形成受原湖心岛和湖岸地形所控制;“大耳朵”形态盐壳形成于20世纪60年代初期的4~5年之内;卫星像片上的“耳轮环线”是盐壳形成过程中的年、季韵律构造线;环状盐壳色调深浅变化取决于卤水层埋深、盐壳含沙量及地表粗糙度的变化。

Features and Causes of Formation on Ring-shaped Salt Crust in Lop Nur Region of Xinjiang, China

The Lop Nur Lak region is located in the inner area of Eurasia,adjacent to Aljing Mountain at the sout,kulutage Mountain at the north,Beishan Mountain at the east and kuluk Eesert at the west.It is the lowest reach of Tarim kiver,kongque River,cher che kiver and some other rivers.The boundarg of the image of "Large Ear "is approximately at the contour of 780 mabove sea level.This region region is considered as salt desert with estremely dry climte.On the basis of measurement on the spot,analysis of material compositon,and satellite image analysis,some new conclusions on features and causes of formation of ring-shape salt crust in the east lake of Lop Nur have been obtained: in the region of image of "Large Ear",material compositon on the ground surface mainly consistes of roch salt,especially Choride is in the ascendant,Quartz is main composition in crumb minerals;the shape of "Large Ear" in the east lake of Lop Nur is controlled by oringinal island landform in lake center area and lakeshore landform;The image of "Large Ear" formed within 4-5 years in 1960's;The closed circle-shaped "helixes" as seen on the satellite image is yearly or seasonal rhythm tectonic trace marks;The color difference is caused by the change of the depth of brine layer,sandy content in salt crust,and the roughness of ground surface.