Application Of Hyperspectral Remote Sensing In Uranium And Polymetallic Exploration In The Eastern Margin Of Junggar Basin

As a part of the central Asian metallogenic belt, Junggar basin is rich in gold, tin, copper and molybdenum and so on. The study area in this paper, between Kalamaili fault and Aermantai fault of the east of Junggar basin, is abounding of gold and tin. Because of a large area of carboniferous U-rich granite and Jurassic sandstone, the area north of Kalamaili fault is a favorable area of sandstone type uranium mineralization.Based on lots of previous research results, in this paper, remote sensing technique was used to explore sandstone type U deposit, gold ore, tin mine and copper deposit. Airborne hyperspectral remote sensing（CASI-SASI-TASI） data was mainly used to acquire the information such as structure, alteration characteristics in the study area, helped by the data such as ASTER, Quickbird and Landsat 8. During this process, the quantitative calculation of SiO₂ and quartz were obtained, the method of monomineral quantitative calculation was proposed, and the exploration model of remote sensing for prospecting sandstone type U ore and polymetallic ore. On these bases, the locations and scopes of sandstone type U ore and polymetallic ore prospect areas were optimization.The concrete achievements and knowledge have been made as follows,（1） A quantitative algorithm of SiO₂ and quartz was developed with thermal infrared hyperspectral remote sensing.The content of SiO₂ and quartz on the ground can be obtained accurately, because of the congruent relationship between the content of SiO₂ and quartz and the emissivity spectral features in 8.6μm and 9.25-9.75μm. Emissivity peak at 8.6μm is the unique spectral feature of quartz. The absolute hight value of the peak is closely related to the content of quartz. Silicified belt and acid dyke can be distinguished by the map of quartz content and the map of SiO₂ content.（2） The information of structure and a variety of alteration mnerals in the study area were extracted accurately, and it is an important basis of sandstone type uranium deposits and polymetallic metallogenic conditions evaluation.The accurate information of structure and alteration mneral in the study area were extracted by airborne hyperspectral remote sensing, combined with multispectral remote sensing, such as Quickbird, ASTER and Landsat 8. According to the information of different mineralization types, such as structure, alteration mineral assemblage, the polymetallic metallgenic potentiality was evaluated.（3） The metallogenic conditions of sandstone type uranium desposit in study area were evaluated, the minerogenic prospect areas o were obtained, and good mineralization phenomena was found.With strong silicification and clayzation alteration, U-rich granite of study area is a good source of uranium. By the information of silicified and clay alteration, and the quartz content of layer, the uranium source condition, penetrability of runoff area oxygen for oxygen uranium water were evaluated well. Because it is difficult to extract underground mineralization alteration features at this stage, the location of deep orebody is hard to be ascertained.Kalasayi is an important sandstone type U minerogenic prospect area of study area.This prospect area is between Kalasayi fault and Laoyaquan granite pluton, and it is related to the oil and gas of Wulungu depression and Dishuiquan sunken.Thus, the U minerogenic prospect area is a sandstone type U desposit which is caused by multi-factor, such as interplayer oxidation zone, oil, gas and multiple tectonic movement.（4） The minerogenic prospect areas of gold deposit, tin deposit and copper deposit were obtained, and investigation and veritifation effect is good.Airborne hyperspectral remote sensing play important role in gold ore deposit, tin ore deposit and copper ore deposit exploration, because it is able to accurately extract the altered minerals related to polymetallic deposit to determine the location of polymetallic deposits mineralization prospect areas quickly and efficiently. Based on the information of structure, silicified and clay alteration and the quartz content, several minerogenic prospect areas of gold ore, tin mine and copper deposit were obtained. Gold deposit, mainly related to ductile shear zone and mainly distributed in Kubusu fault zone, is confined in Siluran which is gold-rich. Strong silicification and sericitization alteration are distributed around this type gold deposit. Acidic granite type gold deposit maybe exists in Alabiye granite boby with sericitization, kaolinization and propylitization. Tin deposit prospect areas with strong silicification and sericitization alteration are distributed in the north of Laoyaquan granite body. With typical alteration zoning characteristic, porphyry-type copper deposits may exist in the east part of Yijiandijiamankelike granite-porphyry body. The little granite bodies and acid dike with strong silicification and sericitization alteration and high Cu north of Laoyaquan granite pluton are copper ores minerogenic prospect areas. The investigation and veritifation effect in field of these polymetallic minerogenic prospect areas is good and it provides effective remote sensing technology support for study area minerals investigation.