The Geochemistry Characteristics Of The Salt Crust In The Lop Nur's Great Ear Rings Area

This article take the salt crust of Lop Nur great ear rings as object of study, which analyzes through in the field investigation sampling and in the laboratory. The local modern salt crust landform deposition characteristic were studied, and its ring-like image characteristic and the electric conductivity apparatus observed relevant value, which have carried on the discussion. The component of salt crust and the spatial distribution characteristic as well as the underground bittern hydrochemistry characteristic were studied. The results show that:1,From the center of the lake to its shore in 50 kilometers, It concerns that the surface elevation change and difference of salt crust's thickness and the lake water flinching time length and so on. The curve of salt crust's thickness change characteristic assumes that it has undulating and unceasing accumulation tendency. In the horizontal direction, the salt crust granulometric composition by the thin change into thickening. It is obvious that has level deposition differentiation characteristic, but from the surface layer to the lower level, the sand grains of salt crust content size are more thicker than powder grains or slabby grains, which displays from thick to thin vertical and spatial distribution rule. Among them, the black rings puts in order salt crust sand content to increase, but the white rings puts in order by the silt and the clay primarily. The light and shade interaction annulus of salt crust granulometric composition difference are showed that the saline lake passed by evolutionary process, because of the climate and temperature changes in turns, which causing the saline lake deposit ingredients have regular change results.2,The results showed that each characteristic parameter values of the salt crust soil all expressed distinct space variability. The formation of the great ear rings and the physical quantity expressed through the electric conductivity apparatus had better pertinence. Then the electric conductivity value in the black districts of the great ear is higher than the same in white regions.3,The material compositions of salt crust mainly take Cl -,SO42-,Na+,Ca2+,Mg2+,K+. Its type as SO42--C1--Na+, and Cl-,Na+ are high in the 2-15cm depth, SO42-,Ca2+,HCO3- are high in the 0-2cm depth. Cl -,Na+ and SO42-,Ca2+ assume the opposite tendency, K+,Mg 2+,CO32- and Cl -,Na+ are similar change, they are highest in the 2-15cm depth. Ca2+ are rich in the surface layer of salt crust in the white rings, but Cl -,Na+,SO42-,K+,Ca2+,Mg2+ are rich in second layer. With its opposite, SO42-,Ca2+ are rich in the surface layer of salt crust in the black rings, but Cl -,Na+ are rich in second layer.4,The total salt content of salt crust displays the center of the lake and the lake shore boundary zone is low in the Lop Nur, but the middle position is high, namely among high both sides low tendency. But the total salt content of salt crust assumes a variety of fluctuation and opposite tendency in the black and white rings. Its atoll structure and the salt content are different change. The saline lake has experienced initial periods in Lop Nur. The intermediate stages and later periods are three times approximately in the dry process.5,The underground water of salt crust is rich in the crystal bittern primarily. The hardness index is high, because of the bittern evolved degree is different, its chemical composition content has the obvious difference. Among them, there are high in Cl-,Na+,SO42- primarily, and contains K+, Mg2+ richly, but poor CO32-,HCO3-,Ca2+. The type of hydrochemistry is magnesium sulfate hypo-type.