Geochemical Characteristics Of The Dahongshan Copper-iron Ore Bed, Yunnan

In this paper, dahongshan copper iron ore bed in yunnan province as the research object, through the extensive collection of the former data, followed by field geological survey, sample analysis, and indoor comprehensive research, summarized the orebody characteristics of deposits, geochemistry, ore-forming fluid properties and metallogenic environment.The type of dahongshan copper iron ore bed in our country and even the world is the more famous, and get more attention, located in the southern part of the dianzhong depression, between the honghe fault and lvzhi river fault, aolaoshan group in the west, the east for the kunyang group. Deposits mainly occur in dahongshan group, a set of ancient undersea volcanic eruption～sedimentary metamorphic rocks. The groups from old to new:laochanghe group, manganghe group, hongshan group, feiweihe group and potou group. Copper is mainly concentrated in mangang group, iron ore at the hongshan group. Mining area magma activity was frequent, with multi-phase, multi-cycle characteristics. Accompanied by phases of tectonic movements,had different levels of magmatic activity, from plutonic rock out to, from the super mafic rocks to acidic rock are the exposed.The formation process of dahongshan group and the causes related to the ancient geographical environment, the sea sediments and submarine volcanic activity, its deposition cycles and the formation of deposits had a fairly close relationship, the dahongshan group bottom-up roughly divided into five large deposition cycles. In addition, the output of the distribution of deposits controlled by tectonic and volcanic agencies, in the periphery of the volcanic bodies, the orebody gradually pinchout disappear.The geochemical characteristics of mine rock and ore are broadly similar, the main amount of element-rich sodium, trace elements-rich iron,copper and so on,and with thecharacteristics of marine volcanic sedimentary and normal deposition,isotope analysis also confirmed this point. According to the test analysis of the inclusions, studied the nature of the ore-forming fluids, evolution,ore-forming temperature and depth.Comprehensive above research, inferred the mineralization process which ancient undersea volcanic eruption caused. At different stages of volcanic activity, there are special metallogenic environment and condition. Volcanic jet, volcanic breccia and volcanic ash deposition controlled of copper, The iron ore was controlled by the overflow of the iron-rich magma and volcanic, and in the later received a degree of regional metamorphism and hydrothermal influence which richest or dilution effect, made the final form of today dahongshan type copper iron ore bed.