| The Wangjiadagou gold deposit is located in the northern part of the North China platform,the Liaodong block,the Tieling-Jingyu ancient uplift and Fushun-Xinbin uplift in the middle part of the tertiary tectonic unit,it is a typical distribution area of the archean granite-greenstone belt in China.The Wangjiadagou gold deposit occurs within the acute angle of the intersection of Hunhe fault and Suzihe fault.The main strata exposed in this area are Shipengzi Formation and Hongtoushan Formation in Anshan Group of New Archean.The magmatic rocks mainly consist of Archean-Proterozoic Azepathite granite and gneous granite,Late Jurassic granite and intermediate-acid dykes and Late Cretaceous basic-ultrabasic dykes.The vein rock is relatively developed,mainly including pharitic rock,lamprophyre,chernozem erbenite and diabase.The alteration of surrounding rock in the mining area is relatively developed,mainly distributed in and near the mineral-bearing fracture zone,and the main alteration includes silicification,sericization,ferric sericization,potassization,chloritization and carbonation.The Wangjiadagou gold ore body is strictly controlled by NW trending shear fault structure.Gold ore bodies occur in ore-bearing fault zone or its upper and footwall,and their occurrence is basically the same as that of ore-bearing fault,showing a slow wave shape along the strike and trend.The shape of ore body is veins and thin veins,followed by the shape of lentil,with the characteristics of expansion,contraction and sharp extinction.The structure of the ore is dominated by semi-autogenous granular structure,followed by cataclastic structure,metasomatic corrosion structure,emulsion droplet structure,including structure,etc.The ore structure is mainly fine grain disseminated structure,followed by brecciated structure,banded structure and veined disseminated structure.The mineral composition of the ores is relatively simple,the metallic minerals are mainly pyrite,followed by chalcopyrite,galena,sphalerite and trace ag-Au,etc.Quartz is the main matrix mineral,followed by carbonate,sericite and a small amount of white mica,chlorite and so on.The main gold-bearing minerals are pyrite and quartz.Followed by galena,sphalerite,chalcopyrite and so on.The natural ore types in this area are mainly gold-bearing quartz vein type,gold-bearing altered rock type and gold-bearing breccia type.The gold and silver minerals in this area are mainly silver and gold deposits and a small amount of gold and silver deposits.There are occasional natural gold deposits in granular,wheat granule,leaf,needle-vein forms.The occurrence of gold deposits mainly consists of fissured gold,interstitial gold and encased gold.The gold deposit is mainly controlled by NW compressional structure,and the mineralization thickness increases and the mineralization is good in the zone with slow occurrence.A group of NW vein mineralization and enrichment have horizontal correspondence,which can be used as prospecting indicator.The alteration of surrounding rock is mainly silicification and sericinization,and the fine pyrite is the main gold deposit.The ore-forming fluids are mainly gas-liquid inclusions.Metallogenic stage?:uniform temperature from 283.1?to 294.2?,the salinity is 18.96?19.71 wt%Na Cl,density is 0.92?0.94g/cm~3.Metallogenic stage?:uniform temperature from224.2?to 252.1?,the salinity is 18.19?21.13 wt%Na Cl,density is 0.97?1.00g/cm~3.Metallogenic stage?:uniform temperature from 181.9?to 219.2?,the salinity is17.10?22.59 wt%Na Cl,density is 0.99?1.03g/cm~3.Metallogenic stage?:uniform temperature from 148.6?to 169.4?,the salinity is 18.45?19.05 wt%Na Cl,density is1.04?1.05g/cm~3.On the whole,as the temperature decreases,the fluid salinity tends to decrease,and the density increases obviously,which is mainly related to the fluid boiling and gas phase escape.The ore-forming pressure is estimated to be 22.91?29.83mpa,and the corresponding ore-forming depth is 2.29?2.96km,which belongs to shallow mineralization.According to potassium-argon dating,gold mineralization in the area was later than that in the Indo-Chinese epoch.Based on the spatial distribution and genetic relationship between Wangjiadagou gold deposit and Nankouqian granite,the final location of gold mineralization should be Yanshan Period.The sulfur isotopic composition of pyrite is mostly close to that of meteorite.The analysis shows that the minerals mainly come from deep magma sulfur minerals.According to the analysis results of quartz oxygen isotope samples in the quartz vein,it is considered that the ore-forming hydrothermal fluid mainly comes from magmatic water,with atmospheric water added.The deposit type is medium(low)thermo-hydrothermal vein type gold deposit.Qingyuan area is a typical distribution area of the archeangranite-greenstone terrains.It contains abundant gold,copper,iron ore and other resources related to the greenstone belt.It has excellent ore-forming conditions and good prospects for regional prospecting.Based on the detailed study of the regional geological background,geological characteristics,orebody geological characteristics,ore-forming geological conditions,ore-forming enrichment rules and genesis of the gold and copper deposits in Wangjiadagou gold deposit,the distribution and metallogenic laws of the gold and copper deposits in Qingyuan area are briefly summarized,and detailed prospecting criteria are put forward,metallogenic prospect area was divided.which provides a good reference for the future mineral exploration work. |
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