Forecast Of Geology-geochemistry Prospecting For Gold Polymetallic Deposits In Bangzhuoma Area,Longzi County,Tibet

The Bangzuoma research area is located in the southern part of the Qinghai-Tibet Plateau,in the middle east part of the Tethys Himalayan metallogenic domain.As the ore-forming geological conditions in southern Tibet are extremely advantageous.In recent years,Many typical polymetallic deposits,such as gold and antimony have been found in southern Tibet.In order to realize breakthrough in ore prospecting in Bangzhuoma,southern Tibet,This article takes gold polymetallic ore as the research object,based on systematic collection of regional geology,geochemical exploration,and other field geological surveys,in-depth study of regional metallogenic geological background,rock Geochemistry,1:1 million soil geochemistry and other characteristics and the distribution and production characteristics of typical metal deposits in time and space,summarizing and summarizing regional ore-forming laws,and extracting information related to mineralization,established a set of Geological-geochemical prospecting models,eventually delineated three prospecting targets in the study area.Through the analysis and research,the following main results are obtained:?1?Affected by the collision between the India Plate and the Eurasian Plate,the areas near the east-west fracture structure,northwest-trending fracture structure,near-north-northward secondary fracture structure,and metamorphic core complexes play an important role in the formation and distribution of gold-polymetallic deposits in southern Tibet.?2?The Upper Triassic Nieru Formation is the main ore-bearing horizon in the study area,and the second and third segments of the Nieru Formation are the most significant.The magmatic rocks associated with ore formation have basic rocks and acid rocks,and the intrusive activities of magma have an important influence on metallogenesis.The north-west fracture structure in the area has a certain control effect on Au,Au-Sb and other polymetallic mineralization.?3?The rock geochemistry of the diabase in the study area shows that the Diabase formation time is 137.7±0.9Ma,which is earlier than the formation time of the adjacent gold antimony polymetallic ore.The content of SiO₂ in the diabase is42.37⁵1.70%with an average of 48.65%;the content of K₂O is 0.12¹.63%with an average of 1.13%;the Na₂O content is 2.46⁴.38%with an average of 3.31%;K₂O+Na₂O is 3.19⁵.54%,average 4.56%;K₂O/Na₂O 0.04⁰.94.According to Zr/Nb-Y/Nb and Ta/Yb-Th/Yb diagrams,the basic rocks in the study area are characterized by enrichment of the mantle.According to the Th/Ta and Zr/Hf ratio,the basic magma may be mixed with continental crust in the process of invasion.?4?Using the elemental coefficient of variation,element enrichment and discrete features to analyze the soil geochemical characteristics of 1:1 million,it is concluded that the Au,Ag,W,Pb,and Sb elements in this area have a large metallogenic potential.According to correlation analysis and factor analysis,there are 4 groups of elements in the study area,among which 3 groups of elements contain elements with large metallogenic potential:Au-Ag-W-Cu-Bi;Pb-Sn;Sb.?5?By extracting the information of strata,structures and magmatic rocks in the study area,and combining with the extraction of soil geochemical anomaly information,the geochemical prospecting model was established.At last,three mining target areas were identified in the study area,and the target areas were evaluated,and the local anomaly areas in the target areas of No.1 and No.3 were verified by engineering.This provides a theoretical basis and idea for further mining exploration.