| The Tianshuihai area,located in the Cenozoic intraplate regeneration orogen in the West Kunlun Mountains,and the combinative region of Mushitage-Aksai Chin metallogenic belt and Lin Jitang metallogenic belt,belongs to Tianshuihai-Beiqiang Block.The main structural direction is distributed in the NW-NW direction,and the tectonic activity is characterized by multilevel,multi-stage and multi type.Based on the study of typical lead-zinc deposits,including Duobaoshan lead-zinc mine and Tianshuihai lead-zinc mine,the remote sensing prospecting model for stratabound lead-zinc deposit and clastic type lead-zinc deposit was set up.Using the multi-resolution remote sensing data,geological and geochemical data of the study area.The prediction of the prospecting area has been carried out.At the same time,two sets of remote sensing alteration information extraction and optimization methods have been developed.1)An improved Crosta technique is proposed to extract specific alteration information effectively.The spectral bands corresponding to the specific absorption peaks of the altered minerals were selected to concentrate the alteration information into a specific principal component by principal component analysis.The method could effectively obtain specific hydrothermal alteration in the covered and shadow areas.2)An new method was proposed to extracted hydrothermal anomaly from remote sensing data.Based on the scale of mineralized altered geological body,a 2-D low pass filter is designed,and the alteration information of regional geological body is obtained by low pass filtering of remote sensing alteration information layer.Then,the difference between the original alteration anomaly and its background information is used as the remote sensing alteration,which aims to reveal the local mineralization.3)The characteristics of remote sensing alteration of typical lead-zinc deposits in Duo Baoshan lead-zinc mine and Tian Shuihai lead zinc deposit are analyzed and summarized.The variation of iron and carbonate corrosion in the Duo Baoshan lead zinc mine is often distributed along the fault,fault intersection and its surrounding rocks.The Tian Shuihai lead zinc mine presents a variety of alteration anomalies in the clastic sedimentary strata,and the central hydroxyl alteration anomaly is of high value,and the peripheral OH-and iron stain alteration anomalies are high.The center is a hydroxylated alteration zone and the periphery is an abnormal alteration zone of hydroxyl and iron stain.4)Based on the regional metallogenic background in the study area,ore prospecting and forecasting was carried out in the Tianshuihai area.The MapGIS 6.7,MORPAS 3 and MRAS1.0 software platforms were utilized to extract multivariate information,such as geological,geochemical and remote sensing alteration.The weights of evidence method was used to predict the lead-zinc deposits in the study area.12 metallogenic prospective areas and 24 metallogenic target areas were delineated.Field verification,fluorescence analyzer test and perform polished,thin section microscopic observation were treated with flake,all of them obtained a good prospecting results.The effectiveness of the technical method is proved.After optimization,the technical combination of mineral exploration methods will provide good technical and achievement support for the prospecting work in the deep cold cutting mountain area. |
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