Prediction Of Potential Copper Resources In The Milashan Area And 3D Prospectivity Mapping In Qulong Porphyry Copper Deposit,Tibet

Milashan research area is located in the middle east of the famous Gangdese metallogenic belt of the Tibetan Plateau,the southeast of the junction of the central Lhasa terrane and the South Lhasa terrane.There are a series of large-scale,super large and medium-sized porphyry-skarn copper polymetallic deposits,such as Qulong porphyry copper deposit and Jiama skarn copper deposit.Previous studies on the geology,structure,magmatic evolution and mineralization of the Milashan area have been carried out,but the quantitative prediction work is still not enough.In this paper,2D quantitative prospecting prediction is carried out for Milashan area,and 3D deep prospecting prediction analysis is carried out for the Qulong porphyry copper polymetallic deposit.The paper is aimed at excavating the potential orebody in Milashan area so as to provide effective support for the supply of China's strategic resource reserve and the next exploration.This paper used a variety of information extraction methods to process and analyze the geological and geochemical exploration data in the area,all based on in-depth research of the correlation between strata,structure,magmatism and mineralization in Milashan area.The results based on the analysis of 1:50000 stream sediment geochemical data show that the C-A fractal method is a better way to identify the geochemical anomaly.According to the favorable information of ore prospecting in Milashan copper deposits,a prospecting model is established,and the prediction variables are optimized.The results show that there is a closer correlation between Cu geochemical anomalies and copper mineralization,compared with others factor layers.Eight prospecting and prediction areas are delineated by the Weight of Evidence method,including two class A prediction areas,three class B prediction areas and three class C prediction areas with the MORPAS software.In the study of Qulong porphyry copper deposit,based on the collection of relevant exploration data,the drilling database is established,and the 3D geological model of orebody,rock models and alteration models are completed with the Micromine software.The main results show that:(1)the concentration distribution of Cu element in the grade interpolation model shows that the mineralization boundary has been exposed in the north and west of the ore body;(2)the ore-forming porphyry body is mainly developed in the middle of the ore body shallow position(500m),indicating high-grade mineralization(Cu?0.4%),and the early ore-forming body is the main ore bearing body;(3)The mineralization degree of the superimposed part of sericite and potash(including the later superimposed argillization)is better.On the basis of the 3D quantitative prediction and evaluation model,two deep prospecting targets and one edge prospecting target are delineated by using the Weight of Evidence method.