Mineralization Diversity And Quantitative Evaluation Of Gejiu Tin-copper Polymetallic Deposit

Gejiu tin-copper polymetallic deposit has a hundred years of study history, which have been thoroughly studied into all aspects by a large number of experts and scholars from both at home and abroad, receiving a great deal of achievement. But It is influenced by previous guiding ideology of prospecting, the prospection and exploitation is focused on the surface tin deposits, skarn sulfide deposits and interlayer oxide deposits for a long time, they do not pay enough attention to the altered granite porphyry deposits, the deposits is associated with lamprophyre and exhalative-sedimentary. These different mineralization characteristics determined the very obvious variety of Gejiu tin-copper polymetallic deposit, the spatial distribution and variation of the deposits is very obvious, which are Surface placer, interlayer oxide deposits, and the skarn sulfide deposits from top to bottom, and in recent years the altered granite deposits was found in east Laochang area. The deposit genesis view of Gejiu tin-copper polymetallic deposit is increasingly recognized, which is from the magmatic hydrothermal genesis theory to submarine exhalative sedimentary, to the Multiple periods, poly sources and compound mineralization, with the deepening understanding of the deposits and the new type deposit being found, the genesis diversity of Gejiu tin-copper polymetallic deposit is continually enrich, predecessors have been researched about the diversity of mineralization in Yunnan Gejiu tin-copper polymetallic deposit, Since the diversity of mineralization and the spectrum of mineral deposits were proposed, but with the new deposit type was found and the further studies improved in recent years, the diversity of mineralization and the spectrum of mineral deposits is remained to be perfected in Gejiu area.This paper is regarded triple quantitative mineral prediction theory as guidelines, which proposed by Zhao Pengda et al. the research Object of Triple quantitative mineral prediction theory Mainly include geological anomaly, the diversity of mineralization and the spectrum of mineral deposits, which is built on the analysis of geological anomaly, and guided by the diversity of mineralization and the spectrum of mineral deposits characteristics; and it research the various information and features of mineralization, the quantify mineralization regularity, we can clearly recognize the causal relationship, getting to strengthen the study of the correlation about geological anomaly (reason)-the diversity of mineralization (forms)-the spectrum of mineral deposits (rules). It is to analyze the characteristics of the diversity of mineralization, and based on that study the spectrum of mineral deposits. Put the predicted deposit in the whole spectrum of time and spectrum of spatial and spectrum of genesis, in order to predict mineral deposits. This paper analyzes the characteristics of the diversity of mineralization from the metallogenic epoch, spatial distribution, metallogenic material source and genesis types and other aspects in Yunnan Gejiu tin-copper polymetallic deposit, establishing the time spectrum and the spatial spectrum and the "time-space-genesis" comprehensive spectrum, which is based on the studied of Gejiu tin-copper polymetallic deposit. On this basis, it explores similarities and differences about these metallogenic diversity characteristic of Gejiu deposit types through compared metallogenic diversity geochemical features and spatial characteristics in different deposit types. It is quantitative prediction and evaluation of the main metal mineral resource potential in Gejiu eastern district using last two steps of the "5P" quantitative metallogenic prediction method. Secondly, it evaluated deep exploration prospect area as Xi’ao copper polymetallic deposit in LaoKa rock of Gejiu. The main results of this paper are:1. Frequent magmatic activities and tectonic movements were frequent in Gejiu tin-copper polymetallic deposit, which led to the complex metallogenic geological condition and wide variety resources, it provide the basis for the study on the diversity of mineralization. This paper analyzed the characteristics of the diversity of mineralization in Yunnan Gejiu area respectively from the metallogenic epoch, the spatial distribution of deposits, metallogenic material source and genesis types etc.2. This paper accords to ore formation and metallogenic epoch built four metallogenic series on basis of the diversity of mineralization analysis, combined with the results of previous studies. (Ⅰ), the rare elements, radioactive and nonferrous metal-non metal deposits related to the Yanshan period alkaline rock metallogenic series. (Ⅱ). rare elements, precious metal and nonferrous metal deposits related to granite of Yanshan period metallogenic series. (Ⅲ). nonferrous and precious metal deposits related to the Yanshan porphyry veins metallogenic series. (Ⅳ). rare elements, nonferrous and precious metal deposits related to Himalaya period sedimentary and surface modification metallogenic series. The series of Ⅰ-Ⅲ produces is the product of magmatic hydrothermal endogenic mineralization in late Yanshan period. The Series IV produces in surface reconstruction later from the first three series. The altered granite copper polymetallic deposit is divided into series II, the rare elements, nonferrous and precious metal deposits related to granite period pneumatolytic hypothermal metallogenic sub series (Ⅱ-1).3. It is established the time spectrum and the spatial spectrum and the "time-space-genesis" comprehensive spectrum based on the diversity of mineralization characteristics analysis in Gejiu tin-copper polymetallic deposit of Yunnan. The main mineralization age of Gejiu tin-copper polymetallic deposit is late Yanshan period, it formed post magmatic hydrothermal deposits and other deposits, accompanied by regional magmatic activities and tectonic movements began large scale mineralization. There is a certain scale weathering and sedimentary mineralization in Himalaya period, stood for the interlayer oxide deposits and various types of surface tin deposits. The overall spatial distribution of ore bodies is around the complex rock, which is distribution on that asymmetry annular and zonal distribution. The granite is the center, and ore body characteristics and distribution are the inner contact zone, contact zone, the outer contact zone and surface from the inside-out, and element zoning characteristics shows Be-W, Sn (Cu, Mo, Bi, Be)-Sn, Pb, Ag-Pb, Zn. The genesis types and metallogenic epoch is ordinate, the mineralization intensive area spatial distribution of deposits is abscissa, it established Gejiu tin-copper polymetallic deposit the "time-space-genesis" comprehensive spectrum chart. At last, it compared the spectrum of mineral deposits in different scales based on researching "time-space-genesis" comprehensive spectrum chart of tin polymetallic deposits in southeast tungsten.4. The ore body of the Xi’ao copper-polymetallic deposit lies near the contact zone between granite and marble, the shape of ore body occurs in the winding special part of transforming part from steeply dipping to gently dipping on dip direction. It belongs to small and medium deposits, and its metallogenic elements’tenor is quite high, the average content of Cu is roughly 1.79%, and Sn is about 0.51%. There are many types of wall-rock alteration; the alteration of potash feldspathization, fluoritization and tourmalinization has closely relationship with mineralization. The alteration zones is not obvious symmetry, it can be divided into potash feldspathization zone and epidotization zone according to main types. There can be seen clearly mineralization in potash feldspathization zone. Metallogenic elements most likely come from intrusive granite, and the location of ore body can prove indirectly. It is suggested that the space of ore bodies probably was the path which was the ore-bearing hydrothermal fluid passing though, and formed by filling metasomasis, according to the shape of ore bodies, spatial distribution and mutation. Metallogenic elements should mainly migrate in the form of fluoride and chloride complex.5. it select typical metallogenic types deposits of Gejiu tin-copper polymetallic deposit in different ore fields, mainly including interlayer oxide deposits, skarn sulfide deposits of contact zone, sulfide deposits of alteration basalt and altered granite copper polymetallic deposits. Compare geochemical characteristics of these different types deposits in different ore fields. These different mineralization types of deposits’trace elements and rare earth elements as the research objects, and it mainly compares ore-forming elements and associated elements content, trace elements correlation, REE characteristics and elements characteristic value and other geochemical characteristics.6. Selecting the four metallogenic types as above, according to the ore-forming elements content in the deposits as study objects, and comparing the same metallogenic types of deposits space distribution, main ore-forming elements, the content copper and tin, content value height, high value interval distribution, and the content changes of metallogenic elements in vertical direction from different ore fields.7. it evaluated quantitative prediction and evaluation of Gejiu eastern district main metal mineral resource potential, on the basis of diversity of mineralization and mineralization pedigree established, combined with Yunnan Gejiu research lever and relevant information gathered, using last two steps of "5P" quantitative metallogenic prediction method for quantitative evaluation of Gejiu eastern district. It delineated five areas of potential mineral resources and evaluated, the larger mineralization potential areas are Songkuang West target zone (Ⅱ), Zhuyeshan target zone (Ⅳ) and Dabaiyan South target zone (Ⅴ). Secondly, it evaluated deep exploration prospect area as Xi’ao copper polymetallic deposit of Gejiu LaoKa rock, when search for such deposit, we need to identify alteration features, especially K-feldspar alteration. We can use anomaly features of the trace elements from different elevation tunnel such as Cu, Sb, Bi, Pb, Sn, Cd and Be, to assist judges, it has different anomaly in deep, corresponding position at the top of ore body. The erich elements of supra-ore halo can be used as one of the basis of the existence of deep ore body in the rock shallow area, such as As, Ag, Pb and Zn. There are some elements such as Sr and Ba, which distribution of primary halo is very characteristic, this feature could be used to speculate rock interface.