| With the rapid development of economy and society in China, the demand for mineral resources especially copper and iron rapid increased, increase domestic mine resource reserves, to reduce dependence on the international market, is significant for the national economic security. Dongchuan copper orefield is a famous and super large copper production base in Yunnan, as an old famous mines at home and abroad, with a high degree of research, but mostly focus on Dongchuan type (include Tangdan subtype, Luoxue subtype and Yinmin subtype) copper deposit, the research deta of predecessors about Xikuangshan type ferro-copper deposit is relatively little. The studies of predecessors were focused on the larger structure of Xikuangshan type ferro-copper deposit in Dongchuan copper orefield, but the attention of growth fault in Xikuangshan fault basin is not enough; On the research field of ore-forming fluid in the Xikuangshan type ferro-copper deposit, the studies of previous mostly focused on the temperature, salinity, pressure environment of ore-forming fluid and the study of fluid inclusions in gas, liquid ingredients relatively little; On the genesis of Xikuangshan type ferro-copper deposit in Dongchuan, many scholars have different viewpoints, but basically all recognize the important role of the volcanic eruption in the deposit formation. The paper use some methods as geological structural analysis, stable isotope geochemistry, Re-Os isotopic dating, fluid inclusions geology, detailed analysis the geochemical characteristics of the deposit and the source of ore-forming materials on the visual angles of stable isotopes and fluid inclusions and so on, comprehensive discussing the metallogenic geological characteristics on the visual angles of the stratigraphy, tectonics, igneous rocks, ore body, ore and wall-rock alteration and so on, summarizes the role of ore-controlling of growth faults, and obtained the following major conclusion:(1) The Xikuangshan type ferro-copper deposit in Dongchuan was controlled by growth faults, Luoxue-Yinmin fracture zone that is a north-south strike growth faults controlled the spread of ancient volcanic vent, the size of the basin was controlled by the boundary faults of Xikuangshan fault basin such as F44fault with the strike of N60-80°E, so controlled the scale of ferro-copper deposit that deposited in the basin. The growth faults have the features of the control of rocks and ores, the thickness of rock formation and ore body in upper wall and footwall is different, growth fault was a channel for hydrotherm jet-flow, and played the role of communication underground heat source.(2) Stable isotope composition characteristics indicate, the source of ore-forming materials such as copper and iron into was from volcanic eruptions, show the characteristic of the volcanic jet-flow deposit. Homogenization temperature of fluid inclusions in the ore-forming fluids was middle-high temperature hydrothermal fluid, through raman spectroscopy and quadrupole mass spectrometer,the test results show that the gaseous phase composition of the copper-contained quartz fluid inclusions is water vapor, CO2and CH4, and the rain accounted for the vast majority of the ore-forming fluids.Re-Os isotope dating results show that the different types of ore have different ages of mineralization, with the feature of multiple mineralization.(3) There was many researches of numerous scholars on the genesis of Xikuangshan type ferro-copper deposit in Dongchuan,most of them agreed with that volcanic eruption participated in mineralization. Papers based on analysis of previous research data, through the study of the metallogenic geological characteristics, isotope geochemistry features, fluid inclusions, geochronology, the ore-controlling of growth faults and the contrast between this deposit with VMS type deposits, BIF type iron ore, proposed the ore-forming process that volcanic jet-flow(deposit) hydrothermal (repeatedly) superimposed. |
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