Distribution And Existing Form Of Elements In The Covering Surface Over Gobi Desert Terrain

Gobi desert terrain is a district that the resource potentiality is high, exploration degree is low and difficulty of exploration is heavy. But the resource buried under the deposit make it exploration focus. At present there are the following biggest problem for geochemistry exploration sampling over Gobi desert terrain. 1, Interference of wind and sand, it is mainly distributed in 60-120 mesh. 2, Influence of the covering. Because of the special landscape of Gobi desert terrain, most of its earth's surface is covered by desert soil, and its thickness is from ten meters to dozens of meters. Influenced by these covering, it is difficult to quarry ideal and representative samples. So it is crucial to geochemistry exploration over Gobi desert terrain to avoid the interference of above two situations, find the information of the bottom of covering accurately and make cost-effective sampling scheme.This text choose Jinwozi gold ore, Shihongtan uranium ore and Tuwu copper ore to study. The analysis of the distributing rule of the elements over different earth's surface shows that most of elements are concentrated in cemented soil horizon, and enriched in coarse, fraction of the sample. The following distributing rule can be easily conclude from above three different kind of deposit and one background area.(1)Direction elements of including Au, U ore information are enriched in cemented soil horizon of the top of accumulated layer, which has not blocked the most elements. In the background areas, the content of the Au, U is relatively low in cemented soil horizon.(2) Direction elements of including Cu ore information are relatively enriched in weathering incomplete accumulated layer of the bottom of calcium accumulated layer, which relates to geochemistry property of the copper, but other companion elements are enriched in the cemented soil horizon of the top of calcium accumulated layer.(3) Direction elements of including Au, U ore information and companion elements are enriched in the fine fractions of clay. Direction elements of including Cu ore information tend to concentrate in coarse and fine fractions.(4)In active Au, in the form of iron manganese oxide, the content is high in cemented soil horizon, and the difference is obvious with other layer. But U is lively, and it is account for 60% of all the U content. Absorbed exchangeable U take heavy proportion. It can be seen obviously that exploring Absorbed exchangeable U can drawing fine abnormality.On the basis of the result of experiment and test, propose: when carrying on geochemistry sampling over Gobi desert terrain, the cemented soil horizon(10-40cm, 160 mesh) is the best sample; when analyzing the samples in active form, Au in the form of iron manganese oxide and U in the form of Absorbed exchangeable sample can reflect fine anormality.