Geological Characteristics And Prospecting Prediction Of Silver - Polymetallic Mining Area And Peripheral Remote Sensing Images In Yunnan White Cattle Factory

The Bainiuchang silver polymetallic deposite located in Laozhai Town, Mengzi Xian, Yunnan province is one of the rare super large silver deposits in China, which have proven reserves of six thousand tons of silver. The southeastern of Yunnan, where the Bainiuchang deposit area located in, is located in the intersection of south China Block the Indian Ocean Block, and the Yunnan-Tibet Block. So the earthcrust is poor of stability. Regional Exposed sedimentary rock ranges from Palaeozoic to Cenozoic, and only lack Cretaceous formations. Its total thickness is more than29600m. Deep large faults are developed. Honghe Fault, Nanpan River Fault, Wenshan-Malipo Fault, which controlled regional tectonic framework and mineral resource distribution, formed its boundary. Northwest structures are the main structures of the interior region. The next are Southwest structures. The magmatic activity what were mainly basic magma eruption in Hercynian period and acidic magma intrusion in Yanshanian period in this region was very fierce and frequent. Gejiu, Wenshan (Bozhu Mountain), Maguan (Laojun Mountain) are the three exposed Later Yanshanian granite body. The mainly exposed formations in Bainiuchang deposit area Middle and Upper Cambrian and Lower Devonian formations. Structures in deposit area mainly are northwest faults and folds. The magmatic activity in deposit area is strong. Granite porphyry and doleritic veins are exposed in the earth surface of deposit area. And under the bottom of ores body sees hidden granite, granite veins and monzonitic granite veins.The metallogenic was effected by the Later Yanshannian granite hydrothermalism, controlled by regional fracture and orebodies occur in specific stratum. And the ore district had been found several places of gossan. So it has a favorable remote sensing geological prospecting prospect. At present, current mining prospecting work has been carried out, but still lack of peripheral prospecting prediction work. This paper detailed studied the regional geological background and geological characteristics of the deposit; applying TM and ASTER, Quickbird image extracted the remote sensing geological information of Bainiuchang silver polymetallic deposite and its periphery through the instruction of remote sensing geological prospecting theory; explored the relationship between remote sensing image geological information and regional geological structures, geochemical anomalies, the known ore deposits; put forward a new means of prospecting prediction method according to the strategy of remote sensing geological research. Circled prospecting targets. Mainly acquire the following understanding and achievement:(1) Work out a progress of remote sensing geological prospecting:liner-circle structureâ†'abnormal hueâ†'ore-bearing lithologic unitâ†'wall rock alteration anomalyâ†'locating prospecting target areaâ†'target area verification. Put forward a new approach of ore prospecting:remote sensing image geologic abnormal factor weighting appraisal method.(2) Established remote sensing structural interpretation symbol; extracted liner-circle fractures from remote sensing image; qualitatively and quantitatively analyzed the relationship between them and known ore deposits. Propose that the following areas are favarable ore prospecting positions:1) the overlapping areas among larger and smaller scale circle structure;2) areas of NW-NWW structure belt-like distribute areaswithout other directions of liner structures offset it;3) the The liner-circle structure intersection parts.(3) Extracted Remote sensing imagery abnormal hue. It distributes along liner structures, and concentrates within the ring structures. Also it coincides with areas of Pb-Zn-Ag-Sb-Cu-Mo-F high geochemical abnormal value.(4)Divide bedrock into four forms of lithologic units what are medium to thick carbonate unit, clasolite-carbonate unit, basaltic rock unit, Bozhushan granite unit. Among them, clasolite-carbonate unit is the ore-bearing lithologic unit. Using TM image extracted those lithologic units and genareated thematic map.(5) Analyzed in detail the spectral reflectance curve characteristics, area of wall rock alteration mineral in the study. Extracted the Hydroxylate anomaly alteration imformation through the ASTER image processing. And extracted the ferric contamination anomaly alteration through the Quickbird image processing.(6) Circled twelve prospecting targets and classed it. Two of them are grade one, four of them are grade two and six of them are grade three. Proceeded a contrast with prospecting targets and high value geochemical abnormal areas of Pb-Zn-Ag-Sb-Cu-Mo-F elements combination. Two prospecting targets had been carried out drill exploration. All the evidence shows that these prospecting targets have a good ore-prospecting future.