Analyses On The Geological Characteristics And Exploration Perspective Of Shaquanzi Nb,Ta Deposit,Hami

The Shaquanzi niobium-tantalum deposit is an important iron copper polymetallic metallogenic belt in Xinjiang Hami of China:the collision zone between the Tarim plate and the Junggar plate,which is a rare metal deposit in the East Tianshan mountains area.On the basis of collecting and consulting the achievements of previous studies,the ore controlling factors and prospecting criteria of the sand spring are determined through the study of the rock,lithofacies,the radioactivity anomalies,geochemical anomalies,the characteristics of remote sensing images and the tectonic environment of the niobium-tantalum deposits in the Shaquanzi,and the genesis and metallogenic models of the niobium-tantalum ores are summarized.And compared with the same types of mineral deposits in China,we have obtained the following understanding:1.The ore bodies are mainly distributed in the edge zone and the top of the biotite alkaline feldspar granite rock mass.The ore minerals are columbite-tantalite and fergusonite ore,hypidiomorphic and xenomorphic granular textures,sparse disseminated structure,mineral crystals are small,mainly concentrated in alkaline feldspar and dark minerals,The grade of Nb and Ta is low,the average grade of Nb₂O₅ is 0.03×10^-2,and the average grade of Ta₂O₅ is 0.002×10^-2.2.The mining area is located in the transitional area between Shaquanzi-Xiaobaishitou gravity anomaly middle value area and low value anomaly area.the residual gravity high value area,and there is a North East to bead like magnetic anomaly.The radioactive anomaly value of the mining area is generally 2000-10000fA/kg,the highest value is 14336 fA/kg,the radioactivity intensity curve is positively correlated with the changes of Nb,Ga and Y three elements;The geochemical exploration anomalies include unusually high values of radioactive elements such as Nb-La-Y-U,high temperature hydrothermal element anomalies such as W-Bi-Mo-Sn,and anomalous combination features of medium-low temperature hydrothermal elements such as Au-As-Sb;remote sensing iron anomalies and mud morphologies are very strong near the faults;the mining area is mostly characterized by albitization,greisenization,fluorite-lithify,limonitization and so on.The albitization has a positive effect on the enrichment of Nb and Ta.3.The ore-bearing granites are high-potassium,calc-alkaline and peraluminous granites;Th,U,Nb,Ta,Zr,Y,Rb and K are enriched,and Ti,Sc,Cr and REE are depleted;The REE content in rock mass is low and has a wide range of variation.Rare earth element allocation pattern is enriched with light rare earth and negative Eu anomaly.The geochemical characteristics of each geochemistry are in accordance with the characteristics of A1 type granites.It is believed that the magma formed by partial melting of the lower crust and the upper mantle composition,located in the intrad granites formed in the upper crust.The enrichment of the Shaquanzi Nb-Ta ore deposit results from the crystallization of the F rich ore bearing granites and the post magmatic hydrothermal metasomatism.4.The ore bearing granites formed in the continental margin of the Rodinia supercontinent during the Nanhua period.and a series of high permeability fault fracture zones formed,which has formed a favorable space for the magmatic invasion and stay.formed a channel for the upper invasion and the position of the magma,and the subgroup schist of the Tian Hu rock group formed relative seal.The closed environment provides a very favorable environment for ore hosting.5.Granite type rare metal deposits are widely distributed in Southern China,and are important sources of Nb and Ta in China.The Shaquanzi niobium and tantalite ore is similar to other granite type niobium and tantalum deposits in China:deep faults and fissures control ore deposits,the rock mass is compact,the ore body is irregular and cystic,rich in Si-Al and poor in Mg-Ca.The rock mass is generally albitization and greisenization,,the jointed fissure surface is limonitization,the deposit is due to differentiated crystallization and post-epoch hydrothermal transformation.6.Through comprehensive analysis of strata,tectonics,magmatic rocks,anomalies and geochemical anomalies,two prospecting targets have been predicted in this area.I:the deep and periphery of the niobium-tantalum mining area.The abnormal combination are WBiMoSn and other high temperature hydrothermal elements,less-common metals,rare earth metal element and radioactive element,such as NbLaYU,etc.,The comprehensive characteristics are highly matched with the characteristics of the Shaquanzi niobium tantalum mining area.Is a type A mineral foreground area.II:the area of the Heishan area.It consists of two sets of anomalies of CoZnCdTiFe and NbWLiPMoZrY.Is the favorable target for less-common metals,rare earth metal elements?such as Nb and Mo?crystallization by alkaline-basic magma and post phase hydrothermal solution.Is a type B mineral foreground area.