The Relationship Between Palaeo - Salinity And Palaeo - Temporation And Its Metallogenic Relationship In The Salker Copper Deposit, Wuqa Count

The Sarekebayi sub-basin, which located in southwestern margin of Tarim basin, has large amounts of resources such as copper and coal mine. The Sareke copper deposit is a typical deposit in this area. This paper takes the Sareke copper deposit as the research object, According to the calculation of the paleogeotemperature and paleosalinity of Jurassic and Lower Cretaceous, restore the paleogeotemperature and paleosalinity of the basin and explore the relationship between copper deposit and the paleogeotemperature or paleosalinity. According to the purpose of the research above, The main achievements and new viewpoinis can be summarized as follows:1. The preliminary enrichment of copper has close relationship with the higher paleogeotemperature of the Sarekebayi sub-basin. According to the quantitative analysis of paleosalinity through the equivalent boron determinate method suggested by Walker, show the characteristics of paleosalinity and the sedimentary environment in the Mesozoic era as follows:The paleosalinity of Lower Jurassic Kangsu formation is 9.8%o to 31.1‰, the paleosalinity of Middle Jurassic Taerga formation and Yangye formation is 11.5‰ to 34.9‰ and 10.1‰ to 29.6‰. The results display that the sedimentary environment of these formation is mainly semi-saltwater and saltwater. The paleosalinity of the second lithologic section of Upper Jurassic Kuzigongsu formation is 3%o to 20.3%o, indicating that the sedimentary environment is mainly semi-saltwater.The paleosalinity of the first lithologic section of Upper Jurassic Kuzigongsu formation is 0.8‰ to 20.3‰, the paleosalinity of Lower Cretaceous Kezilesu formation is 0.8‰ to 20.3‰, displaying that the edimentary environment of these formation is mainly freshwater.2. It has abnormal paleogeotemperature structure in the Sarekebayi sub-basin. Restoring the paleogeotemperature of Jurassic and Lower Cretaceous by using chlorite geothermometry. The paleogeotemperature of Upper Jurassic Kuzigongsu formation is 188℃ to 237℃, the paleogeotemperature of Lower Jurassic Kangsu formation is 214℃, the paleogeotemperature of Middle Jurassic Taerga formation is 211℃, the paleogeotemperature of Middle Jurassic Yangye formation is 210℃, the paleogeotemperature of Lower Cretaceous Kezilesu formation is 121℃ to 238℃.3. In the Sarekebayi sub-basin, the chlorite formation temperature indicate the temperature of the copper enrichment. It has close relationship between the enrichment of copper and the four ancient geological thermal event during diagenesis and later. The paleogeotemperature has abnormal geothermal gradient as a result of the four ancient geological thermal event, such as the diagenesis (163℃ to 217℃), the reformation metallogenic of the basin fluid (188℃ to 219℃), the dolerite intrusion (236℃ to 238℃) and the alteration of dolerite (121℃ to 185℃)4. According to the relationship between the paleosalinity, the paleogeotemperature and the enrichment of copper shows that the Sareke copper deposit has the essential features of deposit-transform copper.It is remarkable controled with the Sarekebayi sub-basin, and it mainly occurrence in the fuchsia ferruginous and argillaceous sandstone, the same as the middle-fan. The main metallogenic stage is superposed and modified mineralization during the four ancient geological thermal event, and it is the metallogenetic condition and mechanism of the Sareke copper deposit.