| Qinghai East Kunlun tectonic belt is important metallogenic belt the famous "Golden Belt", band structure is well developed, the movement of magma frequent and strong, there is a very favorable geological background and form a large-very large deposit geological conditions, the mineral resources is rich. Presently the Gold deposits have been found mainly controlled by the Kunlun fault, the main ore body is distribution where both sides of the Kunlun fault, the fault structure in the region is mainly to move towards something-nearly EW fracture and different levels of secondary pressure or pressure shear fractures, tensile and shear fractures ranking subordinate position, trunk faults control the spread of the strata and rock mass. The region has some other typical feature such as widespread magmatic rocks, complex rock types, the Variscan-Indosinian intrusions is most developed and rock type is mainly granitoids.There are more than different scales of gold altered fracture (veins) found in the study area.Ore types can be classified into quartz vein type and structurally altered rock type,maily of quartz vein type. Ore minerals are pyrite, chalcopyrite, arsenopyrite,galena, native gold, galenobismutite and gustavite, etc. Gangue minerals are quartz,sericite, plagioclase, calcite, chlorite and biotite, etc. Major ore textures are anhedral granular texture, euhedral-subhedral granular crystal texture, cataclastic texture and metasomatic texture,etc. Ore structures are mainly disseminated structure, massive structure, vein structure and net-vein structure,etc. Alteration consists of sericitization,silicification, chloritization and carbonation,etc. Mineralization can be divided into quartz pyrite arsenopyrite stage, quartz polymetallic sulfide stage and quartz carbonate stage from early to late.By contrast REE characteristics to found, Asiha ore the REE has the characteristic is similar to the granodiorite and granite porphyry in Asiha, show the Asiha gold mineralization fluid REE may be derived from granitic porphyry, and it’s related to the porphyry mineralization.The variation range of δ18O、δDv-smow and δ18OH2o of gold-bearing quartz vein from Asiha gold deposit is respectively11.3%o-15.1%。,-59.6%o--117.7%o and2.7%o-9.2%o. Hydrogen oxygen isotopes and laster Raman spectroscopy of fluid inclusion research shows that ore-forming fluid of Asiha gold deposit is mainly from magmatic fluid which contains mantle material and rich in CO2,organic water such as meteoric water interfused at late ore-forming stage.The δ34S values of pyrites vary between+5.0%o and+7.4%o, average value is+5.8%o.Both the characteristic of sulfur isotope and the close relationship which lamprophyre dykes and ore vein have in space show that the metallogenic material is mainly from deep mantle-derived magma,which extract metallogenic material from stratum and rocks at the process of rise and migration.Combined with the previous data and the basis of research results, by means of study Asiha Gold Geological and geochemical characteristics, ore-forming fluid characteristics, contact with Variscan-Indo-orogenic process causes, tectonic setting, the ore body characteristics, ore-controlling structure, wall rock alteration mineral assemblages and element association and the genetic type of the deposit, Asiha gold deposit is a kind of altered rock type gold deposits. |
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