Research On Regularity Of Ore-controlling And Metallogenic Prognosis Of The Huachanggou Gold Deposit In Shaanxi, China

The ore-forming geological conditions, ore controlling factors and the deposits genesis of Huachanggou gold deposit were studied according to the theory and method of the genesis of gold deposits and the metallog-enie prodietion. The location metallogenic regularity, typical reeognition and mineralization of vein of Huachanggou gold deposit were analyzed. Prospecting targets were predicted on the base of tectononic geoehemistry anomaly analysis.The main research findings in this paper are as follows:(1) On the basis of detailed field geological survey and systematic laboratory study including microscope observation, electron probe scanning, X-ray surface scanning, the mineral composition and the occurance of gold has been identified. The results show that Huachanggou gold deposit has a small variety of minerals with pyrite as the dominant mineral and minor chalcopyrite, bornite, sphalerite, galena, pyrrhotite and so on. The gangue minerals are mainly quartz, dolomite and albite. The gold in the ores mainly exists in the form of independent mineral phase. The carriers are pyrite, quartz, dolomite, chalcopyrite and tennantite. The main gold minerals are native gold.(2) The relationship between mineralization and formation, strueture, magma rock were diseussed.The main ore-controlling factors of Huachanggou Gold deposit can be summarized as 3 ponits:a). Formation, the Sanhekou group in Devonian is the main formation which gold deposit located in West Qinling Mountains area, meanwhile it is the major ore host strata and the ore source bed. b). Magmatic rock, The mafic marine volcanic rock-spilite in the Huachanggou gold deposit is lenticular in shape and distributes in phyllite in the Sanhekou Group, middle-lower Devonian and it's one of the most important host rocks and the ore source bed. c). Structure. The ore body controlled by structure significantly, which is mainly This is mainly reflected in two aspects:the first is the shear zone controlled the distribution of gold ore belt, and it's also the ore conducting structure,Au ore body is lying in the shear zone as lens.The distribution of mineralization altered rock is generally not exceed the shear zone boundary. The second is that specific form and spatial distribution rule of ore body were controlled by brittle fracture; In addition the NWW strike fault is the main hosting structure.(3) According to tectononic geochemistry survey in the north zone area and mathematical statistic analysis of data, I worked out structural superimposed halo model of trace elements in North Zone, assoeiation near orebodies were Au-Ag. Comprehensive analysis reveals that there has been eroded orebody upper 950m altitude;The middle part of the orebody exsited from 910m altitude to 870m altitude, and the tail of the ore body exsited at 830m altitude, while the deep distance may exist blind new orebody.(4) The prospecting signs Huachanggou gold deposit can be mainly summarized into 4 aspects:a) formation, the carbonate rock and phyllite in Sanhekou group, middle-lower Devonian strata is favourable metallogenic horizon. b) magmatite, the spilite is one of the most important host rocks and the ore source rock. c) The structure of NWW strik is the main ore-controlling structure. d)The wall rock alteration silicification, chlorite-epidote petrochemical and pyritization are close to the mineralization, which can be used as an important ore prospecting marks.