The Research On Geochemical Characteristics And Potass Forecast Of Halite In Western Tarim Basin

Our country is a large agricultural country. The potass amount of demand reaches millions of tons, but its output is very little. And we have to import a mass of our potash from foreign countries every year. So it is an urgent task for geological workers to find potash deposits so as to solve the problem of depending on input. The conditions of potass forming are very strict: plenty of sources of matter, closed geological conformation and the (?)imate of continuous drought and so on. The large-scale potash deposits that have been found in the world lie mainly in the Cambrian Stratigraphy, Devonian Tertiary. Triassic Stratigraphy, Tertiary Stratigraphy System, the ancient salt lakes of Quaternary period and also in modern salt lakes. The Eurasia is the mainly distributions of the Tertiary potass deposit from the collected datum, and there is a wide perspective of potass. Salty mineral of the Tertiary Stratigraphy System has extensively developed in Tarim Basin of Xinjiang, and the conditions of forming potass have formed.In the geological evolution of Tarim Basin, many transgressions and relictions of the ancient Teris happened, especially in the Cretaceous period and the tertiary, and there have been plenty of sources of salt. What's more, because of uttermost drought and proper sedimentary facieses and paleogeography, many salt, gypsum, carbonate and mud-salt have been deposited. By our fieldwork, above 300 samples have been collected including brine and solid. Among these samples, 43 brine samples and 99 solid halite samples have been analyzed. The item of analysis includes K⁺ Na⁺ , Ca²+ Mg²+ Cl^- SO₄² CO₃²- HCO₃^- Br^- B³+and so on.This paper has discussed the variety of the content of K+ and the Characteristics coefficients of geochemistry, the model of salt forming, the concentration stage of brine and halite and the possibility of potass forming by geochemical analysis of the halite and the brine from Tarim Basin. In the end, it puts forward to the potass perspective.From the geochemical parameters of brine and halite in Western Tarim Basin, we could conclude that the perspective of potass is Kashi Sag and Yangxia Sag. Bycomparing the content of microelement and the geochemical parameters of brine and halite with of normal condensed brine, we know that there is little microelements such as Br and B in Tarim Basin, so we couldn't completely depend on these indexes to judge the condensed stage of brine and halite and the things of potass resource, and this point indicated that Tarim Basin is the intricate area of salt forming and it is the alternative result of sea and land.