Geological Characteristics Of Gold Deposits And Its Prospecting Potential Evaluation, In West Of Chaishuigou Area Of Mangai，Qinghai Province

The study area is located in the northwestern margin of the Qinghai Qaidam Basin insouthern Altyn slope of Akha Teng Shan orogenic belt. Metallogenically, it is located in theeast of Qinling-Qilianshan-Kunlunshan metallogenic domain, Kunlun metallogenic province,Akha Teng Shan late Caledonian asbestos(copper, gold) metallogenic belt.This paper intends to combine all the data and preliminary archivement of mineralexploration between western mine area in recent years and related area (forest covering aranear the study area)in last decades.I based on my professional knowledge, havecomprehensively precessed and analyzed the data and preliminary results about regionalgeology, geophysics, geochemistry, summed up the metallogenic geological characteristics,the regional metallogenic regularity and prospecting potential, and put forward to prospectingdirection for the next step exploration to help the mineral exploration.The following are major achievements obtained in this paper:1. The study area is located in Akha Teng Shan late Caledonian asbestos (copper, gold)metallogenic belt. The metallogenic belt is located in the northwest Qaidam Basin of SouthAltyn slope, corresponding to the East Kunlun late Caledonides Akha Teng orogenic belt.North or North West of the southern Altyn Tagh metallogenic belt is East North xorkol mainfault zone, south or southeast is connected with the late Mesozoic formation in Qaidam Basin,and extending to under the basin. The main structural framework xorkol main fault zone, andthe strata, rock and mineral magma has obvious control effect.2. The study area consists of a set of clastic rock of Ordovician volcanic rock andcarbonate rock combination. In the different period of early Paleozoic (late Cambrian andearly Ordovician), different tectonic units (such as island arc and back arc basin) was dividedunder the background of volcanic sediments. This strata was formed due to long-termdeposition amounts of terrigenous materials, sedimentary cycles of transgression andregression in formation. Reductive sedimentary environment is a very favorable conditionsfor enrichment of ore-forming elements, such as Fe, Cu, Pb, Zn, S to concentrate and depositin various forms, and to drive the Au, Ag elements migration, accumulation, distribution andcontrol of deposits. Eventually a set of strata was formed with high value in multi metalelement background to promote the formation of gold, silver, copper, lead, zinc and othermineralization.3. The ore bearing strata consists of a group of volcanic rock and clastic rock. It isinfluenced by the regional tectonic activities, and changed through ductile brittle and brittle tectonic evolution and transformation, so that the strata is fractured within the secondarystructural belt, and strongly affected in the zone of tectonic deformation, metamorphism,which provided the thermal dynamic condition, precipitation and enrichment for theactivation and migration of gold during formation. Late acidic dike intrusion occurs alongfault structure providing a source of mineral and thermal fluid. Therefore, the geologicalcharacteristics of reginal geology, gold deposit and ore body provided evidences that golddeposits were hosted in the fractured altered zone. The gold activation, migration occurredmainly in the rock and their contact zone, fracture altered zone, so the mineralization isfractured altered rock type. The gold deposits in the study area have similar bachground withthe gold deposit discoceried before and lead zinc, silver and other minerals in region.4. The geochemical anomalies between sediments and soil are correspondent effectivelyin the study area. They extend in nearly East-West zonal distribution and combine of elementsCu, Au, As, and Mo, in which element Au has good abnormal concentration center. Theseanomalies in soil are partly coincided with structural alteration zone on ground. Trenchingalong the local soil anomaly prove the existence of gold ore bodies, so the anomalies can beindicator for mineralization. The geological background of the study area and existinggeochemical anomalies will guide some new finding for the mineralizationin the area.5. The experience in application of prospecting method shows the effective explorationprocess is as follows. The gold anomalies were indentified by soil measurement andpreliminary pretected by trenching. Drilling will be conducted in the proved goldmineralization section to delineate finally gold body.