Characteristic Of Primary Halo And Prediction Of Deep Ore-body Of The Xishanwanyangchang Ag Polymetallic Deposit, Inner Mongolia

The Xishanwanyangchang silverpolymetallic deposit of Wulatezhongqi of InnerMongolia, located in the east margin of Mesoproterozoic-neoproterozoic rift valley zone ofLang mountain-Zhaertaishan inthe north China platform,belonging to Zhaertaishan mountainregions in the central and western Inner Mongolia Autonomous Region,is a hydrothermaldeposit related to the tectonic activities in late.Xishanwanyangchang silver polymetallicdeposit Influenced by the EW-direction and NE-direction fault,it forms a serious oflower-level NE-direction faults and a tectonic metallogenic belt. The silver deposit’s majorore-bearing and main elementary anomalies range are lower Cretaceous BainvyangpanFormation volcanic lava, rhyolite,rhyolite porphyry and rhyolite breccia are main host rocks.The area grows late hydrothermal alterationsuch as silicification, fluoritization, pyritization,ferritization, magnetite, chloritization and a more severe kaolinization on the basal surface.The drill’s anomaly of primary shows thatAg, Au, Zn, Pb andW have a wide high-valueanomaly range,and they are mainly distributed in middle-top of the deposit. The anomaly ofPb and Zn are mainly distributed in the middle-below., and they have a more below trend.Mo，Sb and Cu have a wideouter zone anomaly,some are concentrating distribution, mesozone andinner zone abnormalities are narrow, the high-value anomaly in middle-below of thedeposit.The general anomaly rang of As and Bi are narrow, the mainly anomaly is outer zoneanomaly and it distributing in the deposit, they are also have a little high-value anomaly.Different lithological characters have different zoning sequence. By using the Thickconcentrated method and Zoning index method we can obtained the zoning sequence ofvolcanic and plutonicrocks.According tothe comprehensive analysis, we conclude the axialzoning sequence of the Xishanwanyangchang silver depositfrom top to bottom isSb-Ag-Au-As-W-Pb-Bi-Zn-Mo-Cu.With the correlation analysis we can see that Aghas a positive correlation with Au,Pbhasa close relation with Zn. As the correlation is0.1,the elements can be divided into3groups,the first group is Cu、Pb、Zn、As、Mo; the second is Sb、W、Ag、Au; the last is Bi.Theyare represent different mineralization stages.Ag、Au are the ore-forming elements of the silverdeposit, they are reflect the combination feature about the mineral elements. With the factoranalysis, we can choose5elementassociations which the factor loading are more than0.7. F1is Cu-Pb-Zn，it reflects the mineralization stage with the character of Cu-Pb-Zn; F2isAu-Ag-Sb, it reflects the silver mineralization stage; F3is As-Mo, it reflects it can form sulfide about As-Mo; F4is Bi, it reflects a mineralization stage that about sulfide and oxidewith Bi. F5is W-Sb, it reflects another mineralization stage. We can conclude from above thatIt has undergone at least5mineralization stages.A factor pattern method of Ag establishedafter rotated factor matrix: X Ag=0.19F1+0.873F2-0.054F3-0.007F4-0.170F5.Itreflectsthe Ag mineralization has the character of the same source and period withpolymetallic sulfide.In order to evaluate the deep ore prospecting, we firstly compare the zoning sequence ofXishanwanyangchang silver polymetallic depositwith the axial zonality sequence thatsummarized by lihui et al, it shows that:1. In the ZK13-1on southwest of the deposit,Mo、Cu,the tail halo elements, appear in the middle-top of the zoning sequence. As and Sb, the fronthalo elements, appear in the tail of the zoning sequence. It reflects the reverse zoning law. Wespeculate it may caused by superposition between the tail halo inbelow of the deposit and thefront halo intop of the deposit,With the coexistence law of the tail halo and the front halo, wespeculate that it may has blind orebody in the deep.2. In the ZK15-3, ZK17-1, ZK18-1,ZK21-1inmid of the zoning sequence, the superposition of the tail halo and the front haloindicates that it may has blind orebody in the deep or the orebody may extendes downward.Au and Ag are in the top of the sequence of component, it reflects a serious denudation extentof the deposit.The clustering analysis shows that Ag、Au、Sb and W are in the same group, Ag、Au andSb also have a good correlation in the clustering analysis. The factor F2which the mainelements of load are Ag、Au and Sb has the contributing rate of squares is28.815%.It showsthat the enrich degree of Ag、Au and Sb has positive correlation with content of silver.Theratios (As+Sb)/(Mo+Cu) and (As*Sb)/(Mo*Cu) from down to up rapidly on the change oforebody axial curve shows the reverse zoning and it may has blind orebody in the deep or theorebody may extendes downward.