Ore Genesis And Quantitative Ore Prospecting Of Jiaqi Porphyry Cu-Mo Deposits In Qimantage Area,East Kunlun Mountains,China

The Lalingzaohuo research area is located in North Kunlun magmatic arc zone within the Eastern Kunlun Orogenic Belt(EKOB),which is characterized by wide distributed granitic plutons.A porphyry Cu-Mo deposit is firstly found in the Lalingzaohuo area.In this study,the petrology,geochronology,and geochemistry of the Jiaqi Cu-Mo porphyry deposit are investigated.Intrusions in the deposit can be divided into three units.Granodiorite yields a zircon U–Pb age of 238 ± 3 Ma.Diorite porphyry and granodiorite porphyry yield zircon U–Pb ages of 235 ± 3 Ma and 235 ± 3 Ma,respectively.Abundant diagenetic and metallogenic age collection of porphyry and skarn-related deposits in the EKOB suggest that deposits occurred after the formation of the huge Kaimuqi batholiths.Results of both three amphibole-related empirical barometers and CSD(Crystal Size Distribution)analysis indicate that the Kaumuqi granodiorite batholith,Jiaqi diorite porphyry,and layered granodiorite yield progressively shallowing emplacement depths.Geochemical data of the ore-related intrusions indicate a syn-collisional setting after an oceanic–continental subduction,consisting with the paleosurface shallowing calculated using three kinds of barometers.The Kaimuqi batholith in the Qimantage area is the product of the initiation of intercontinental collision.Felsic intrusion-related deposits were subsequently formed due to the strong magmatic thermal activity.The evolutionary process analysis indicates that even though ore bodies are mostly with the Jiaqi granodiorite,but ore-causing intrusions are porphyries.Therefore,the Qimantage region presents a preferable potential for prospecting porphyry-type deposits beneath the batholith in the EKOB.Futhermore,a novel vein/dike distribution density method is formulated for underlying targets prospecting within the huge granitic batholiths exposed area.Three parameters(vein/dike density,vein/dike orientation density and vein/dike fractal dimension)are proposed to express degree of irregularity and complexity of vein/dike distribution patterns.This method is applied to the South Alatao Mountains area and the Eastern Kunlun(china),where the dike swarms(vein network)show regional-scale(deposit-scale)well-developed density gradients,respectively.All of these results indicate that the method is an effectively quantification tool for prospecting mine targets.It is an effective and complimentary technique for the common mine prospectivity analysis.The method also documents the high potential of mine prospecting below huge granitic batholiths.