Genesis And Exploration Of The Jiuloudong Ag-Au Polymetallic Deposits,Southern Jiangxi Province

The Jiuloudong deposit is located in the Yudu-Yinkeng to Ningdu-Qingtang precious metals polymetallic metallogenic belt,southern Jiangxi province,which is the most important precious metal polymetallic metallogenic belt in the Tungsten ore concentration area,southern Jiangxi province,located in the western Ningdu-Anyuan deep fault.The Yinken district in Yudu county has achieved a great progress in mineral prospecting,and plenty of scientific works also have been carried out,as a result,a series of significant progress have been made,but the research carried out in Qingtang district,which is also located in the Yudu-Yinkeng to Ningdu-Qingtang precious metals polymetallic metallogenic belt,is relatively poor.Although the Jiuloudong deposit in Qingtang district has a long history of geological prospecting,it still lacks a definite recognition of the genesis of the deposit and the characteristics,so this district is of great research value.Based on detailed field,geophysical and geochemical works,in combination with the indoor petrology observation,mineragraphy and fluid inclusion study,we carried on discussion on the genesis of the deposit,and do a further analysis of its ore-forming potentiality.The deposit occurs Nanhuan system Xiafang Formation and Carboniferous Shuixin Formation.Ore body is controlled by the NEE fracture zone between the layers and NE fault ruptured zones.Based on ore minerals and fabrics investigation under the microscope,ore minerals are dominated by nature silver,argentite and pyrite,subordinate sphalerite and chalcopyrite.Gangue minerals mainly consist of quartz,diopsite and calcite.Ore structure mainly consists of vein,veinlet,and net vein,minor disseminate and lumpy.Ore texture is predominanted by an hedral grain texture.1:50000 stream sediment analysis indicates that the abnormal area of the element combination is large,and the element combination is predominantly Au?Ag?Pb?Cu?Zn?As?Sb and so on,both of them belong to the low-medium element combination;Two magnetic anomalies were delimited according to ground high-precision geomagnetic survey,which caused by tonalite and diorite porphyrite respectively.Two faults were revealed in lines 7 and 11 by EH4 continuous measurement of electrical conductivity profiles,with the coincidence of ore-bearing faults site found in geology.The data of themicro thermometry and laser raman microprobe of fluid inclusions in quartz associated with Ag-Au mineralization indicates that the fluid inclusions can divide into three types:gas-fluid inclusions(1),liquid CO2 bearing three phase inclusions(II)and rich liquid inclusions(?),the ore-forming fluid is divided into NaCl-H2O system and CO2-NaCl-H2O system,with lower middle temperature and lower salinity,the three phase fluid inclusions are paragenetic in space.Combined with the geological characteristics of the deposit and the data of fluid inclusion,we conclude that the Jiuloudong deposit belongs to a meso-and epithermal deposit compared with the typical low temperature hydrothermal deposit in China and abroad and the Yinken deposit which belongs to the same metallogenic belt.The area has superior minerogenetic conditions for meso-and epithermal deposit.It is considered that this area has excellent potential for prospecting combining geophysical and geochemical abnormal features.