Characteristic Of Primary Halo And Prospecting Pattern Of Deep Ore-Body Of The Dulong Sn-in Polymetallic Deposit In Southeast Yunnan

The Dulong Sn-In polymetallic ore deposit is located in the southwestern part of the South China plate and at the junction of the Indochina,Cathaysia,and Yangtze plates.With the Gejiu,Bizhushan compound rock foundations form a near-westward granite belt.These area are both widely exposed the granite and affected the formation of ore bodies.Through the 8 boreholes in Section I of Dulong mining area,applied the methods of mathematical statistics,axial zoning sequence research,geochemical parameters calculation.The geochemical characteristics of the primary halo of the ore body are systematically studied and a deep metallogenic prediction is proposed on this basis.By collecting samples in the borehole,measured the content of each element in the sample to reveal the existence of anomalies in the deposit.A detailed zonation sequence of indicator elements is obtained using the Grigorian's method as follows(from high to low):W?F?U?Ta?As?Mo?Sb?Nb?Bi?Sn?B?Zn?In?Ag?Cu?Pb;Based on the cluster analysis:(Sn-In-Bi-Mo)can be put into one group,which reflects the feature of high temperature elements.The other group is(Ag-Zn-Cu-As-Sb-B)which indicates the feature of low temperature elements.Four significant ore-forming element associations have been identified from factor analysis basing on 16 kinds of halo-forming elements are as follows.F1[As-B-Ag-Cu-Sb-Zn-In],F2[Mo-Bi-F-Sn-W-In],F3[B-U-Nb-Ta],F4[F-Pb].Among the four factor,F1 represents the Ag-Cu-Zn mineralization stage which indicates mineralizations were produced in low temperature late sulphide stage.F2 represents the the high temperature sulfide-oxide mineralizations stage and F3 were related to the high temperature rare radioactivity-tourmaline mineralizations.F4 indicates fluorite-galena mineralizations.These factors indicate the mineralization process of the deposit has undergone at least four different mineralization stages,reflecting the feature of the multi-stage.Finally,a criterion such as(F×As/Sn×Bi)_D can be constructed for evaluating the ore potential in depth.The criterion value is 3.28 on the top portion of the ore deposit,0.32 in the middle-upper portion,4.73 in the middle portion,0.43 0.61 1.29 1.91 in the middle-lower portion and 0.41 at the end portion,illustrating the criterion value decrease abruptly with depth and can be used for predicting the potentials of In and Sn at a given depth.