| The non-ferrous metals, such as tungsten and tin, have been the advantageous mineral resources for a long time in China. However, with the sustained and rapid growth of the economy in our country in recent years, the demand and consumption of tungsten, tin and other metal resources are also increasing. As well, because of the excessive development and the sharply depletion of these resources, the resources situation is not optimistic. Some relevant policies are adopted by the State Council in2008to protect and restrict the mining of mineral resources such as tungsten, tin, antimony, and rare earth metals.Southeastern Yunnan area, attached to the southeastern Yunnan-Guixi tungsten-tin polymetallic metallogenic belt, is an important ore-concentrated area of tungsten, tin, silver, copper, lead, zinc, manganese and other metals, which is located in the junction parts of three tectonic units including Yangzi Landmass, South China Fold Belt and Sanjiang Orogenic Belt. The southeastern Yunnan has experienced complex geologic evolutions, so the geological conditions are favorable for ore-forming, for example, a series of super large to large Tin polymetallic deposits, such as the Gejiu tin-copper polymetallic deposit, Bainiuchang silver-tin polymetallic deposit, Dulong tin-zinc-copper polymetallic deposit, and Xinzai tin deposit were founded in this area. In recent years, with the joint efforts of companies, research institutions, and universities, there was a great breakthrough in monolithic exploration of Guanfang tungsten deposit and Malipo tungsten deposit, which has added more than600,000tons of WO3reserves, and shows that tungsten resources also has presented an enormous resource potential.Based on forenamed background, it’s of great significance to conduct a more detailed study on the tungsten-tin polymetallic deposits in southeastern Yunnan. This paper, based on the study of predecessors, taking the academician of "Three-components" quantitative mineral prediction theory and methods made by Zhao Pengda as guidelines, explores the wide range of performance of the diversity of mineralization through the analysis of ore-forming geological background in southeast Yunnan (N22°50/-23°40’, E103°30’-104°50’). Taking the tungsten-tin polymetallic deposit as the area-focused study, through the analysis of typical deposits, this paper will overview and summarize the time-space evolution of tungsten-tin polymetallic deposits and then establish the spectrum of ore deposits.Through this study, the author gets conclusions and awareness as follows:1. Having experienced a long time and complex geological evolution process, there are present complex stratas, structures and magmatic rocks pattern in the study area. Stratas are relatively complete exposed in this area. The present structural features are very complex, and rock-control structure, ore-conducting structure and ore-hosting structures in this area are the consequence of interaction among complex structural phenomena, faults, folds, magmatic intrusive contact structures at different scales and various small structures together. Magmatic rocks are widespread, especially the two complex granites, Bozhushan granite and Laojunshan granite, formed during the strongest granitic magma intrusion activities in Yanshanian period, are associated with tungsten-tin polymetallic deposits, namely Bozhushan granite and Laojunshan granite.2. Based on the analysis of ore-forming geological background, the author conducted a systematical research on geological characteristics of the typical tungsten-tin polymetallic deposits including Dulong tin-zinc-copper polymetallic deposit, Nanyangtian scheelite deposit, Guanfang scheelite deposit, and Bainiuchang silver-tin polymetallic deposit.3.The complex ore-forming geological conditions as well as the frequent tectonic-magmatic activity in southeastern Yunnan result in a wide variety of metallic mineral resources in the study area. In the study area, more than34kinds of minerals have been found, providing a basis for the study on diversity of mineralization. This paper discussed the diversity performances of mineralization in Southeastern Yunnan from the following factors:mineral types, mineralization conditions and factors controlling mineral (ore-bearing strata and lithological characters, ore-controlling magmatic rocks, ore-controlling structures and ore-forming material sources), mineralization age, genetic type of ore deposits and metallogenetic elements combination, which is benefit for a relative comprehensive understanding of the metallogenic characteristics in this area.4. The study area has experienced tectonic many cycles since Proterozoic, which can be roughly divided into five stages:Jinning cycle, Caledonian cycle, Variscan-Indosinian cycle, Yanshanian cycle and Himalayan cycle. Multiple stages of tectonic evolution provide favorable conditions for the mineralization in southeastern Yunnan. The most beneficial cycles for the mineralization of tungsten-tin polymetallic deposits in southeastern Yunnan are Variscan-Indosinian cycle and Yanshanian cycle, and many greatly economic tungsten-tin polymetallic deposits in this area are formed in these two geological era.5. On the Basis of systematically summarizing the space distribution of tungsten-tin polymetallic deposits in southeastern Yunnan, we found the tungsten-tin polymetallic deposits around granite are also obvious zoned in Laojunshan area, and is similar to Gejiu tin-copper polymetallic deposits, which present space zonation in terms of mineralization type and ore-forming element,. The zonation is mainly manifested in two aspects. Firstly, deposit type shows more or less zoning from inside to outside around Laojunshan granite:magmatic rock typeâ†'metasomatic typeâ†'high-temperature hydrothermal typeâ†'mesothermal hydrothermal typeâ†'epithermal hydrothermal type. Secondly, ore-forming element also shows zoning from inside to outside around Laojunshan granite:W-Sn-Be-Nbâ†'Sn-W-Cu-Znâ†'Cu-Pb-Znâ†'Ag-Sb-Hg (that is to say ore-forming elements combination changes from high temperature to low temperature). Compared with Laojunshan area, the numbers and types of tungsten-tin polymetallic deposits that have been found are relatively less in Bozhushan area, and zonation is also not so obvious.6. Based on the systematical study on the time spectrum and the spatial spectrum of ore deposits,"time-space-genesis" comprehensive spectrum of tungsten-tin polymetallic deposits in southeastern Yunnan province has be compiled. Besides, taking the Dulong tin-zinc-copper polymetallic deposit as an example, the author maked an exploratory discussion on spectrum of mineralization in deposit scale. |
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