Geological Characteristics And Prospecting Of Nidangou Gold Deposit In Hualong County,Qinghai Province

Nidangou gold deposit is located in the south of middle Qilian island-arc,which belongs to Early Paleozoic Lajishan rift belt and Mesoproterozoic Riyueshan-Hualong belt of basement liftup.A lot of polymetallic deposits of gold,iron,nickel,cobalt and other types of deposits are found in this area,which show good metallogenic potential.According to the study on the regional metallogenic geology background information,analyzed the geological features of mineralization of the study aera,genesis of the mineral deposit is confirmed and the metallogenic mode is established.Combined with geochemical and geophysics characteristics,we set up ore-prospecting model and research Metallogenic prediction for the study area.There are wide-spread late Precambrian Liudaogou grop middle rock section andesite and andesitic porphyrite with high gold contents,which provides aboundant of material source.A lot of gold is richded Middle Caledonian Wudaoling granodiorite,closed relationship with ore-body,which provides material source and heat sourth.Parts of the granodiorite itself is ore-body.SN and NW trending is the important rock and ore controlling structure.The gold ores mainly are tectonic alteration rock type,and the quartz vein type take the second place.Ore bodies are mainly hosted in the Middle Caledonian Wudaoling granodiorite and its contact zone with late Precambrian Liudaogou grop middle rock section.Pyritization,silicification,sericite and chlorite have the most close relationship with gold mineralization.On the basis of texture and fabric relationship of the minerals,the stage of mineralization is divided into there periods and four stage,and the quartz-sulfide stage is the primary ore-forming stage.With the medium-basic volcanic eruption and overflow,and intermediate acidic rock intrusive in late Precambrian,which happened before volcanic exhalation-hydrothermal activity,flat and line type alteration zone was formed with gold enrichment for the first time.Middle Caledonian,with the intrusive of Wudaoling granodiorite,post-magmatic hydrothermal emerged.In the process of hydrothermal migration,the exchange of material happened between hydrothermal and surrounding rock.With the change of environment,the material in the solution sediments.At the right tectionic ore-bodies was formed,which led to the formation of Nidangou gold deposite eventurally.Judging by its geological conditions,genesis and formation mechanism,genetic type of the gold deposit is medium temperature hydrothermal structure alteration rock type.The result of soil geochemistry show that Cu,Zn have close relationship with Au,which could be used as indicator for exploring gold deposite.In he light of soil geochemical characteristics,twenty-one Au single element anmalies were identified.The evident high-contrast high value anomalies of Au with large anormal aera,massive anormal points orm the most immediate indicators for Au deposit.Eleven composite anomalies were identified,which the anomailes of AP-3?AP-4?AP-5?AP-6?AP-11 were provided with better matching and strong anomaly.The results of IP intermediate gradient measurements indicate that high resistivity and high polarization and local low resistivity and high polarization are the major ore-prospecting indicators for gold deposit in the study area.Four ore-forming prediction areas are identified in the study area.Meanwhile,prediction?₁ and?₂ areas is first-level ore-forming prediction and prediction?₁ and?₂ areas is second-level ore-forming prediction.And first-level ore-forming predictions are selected as prospecting target.