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The Metallogenic Characteristics And Genetic Analysis Of Lianhuaxin Copper (molybdenum) Polymetallic Deposit, Xiushui, Jiangxi Province

Posted on:2013-03-21Degree:MasterType:Thesis
Country:ChinaCandidate:X Y WeiFull Text:PDF
GTID:2230330362465301Subject:Mineral prospecting and exploration
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Xiushui lianhuaxin copper polymetallic deposit is located in the southwest of theJiuling metallogenic belt, the geotectonic position is in the western part of Jiangnan Upliftfold belt, the Yangzi folded downwarping region adjacent to its north and in its south issouth china fold system. Because of the time which was discovered is short, the study andthe scientific research of this deposit is relatively low. On the basis of the research resultsof the early geological work, and by studying the geological characteristics, elementgeochemistry, fluid geochemical characteristics and isotope geochemistry of Lianhuaxincopper (molybdenum) polymetallic deposit. We preliminary analyse and investigate thecauses and metallogenic mechanism of this deposit. This article made some preliminaryunderstandings as follows:â‘´Through the analysis of the regional geological background and geologicalfeatures,Lianhuaxin is a typical quartz vein-type copper (molybdenum) deposit. NNE, NWand EW trending faults control the shape and genesis of the deposit, which is the mostimportant lead ore tectonic and ore-controlling structure. The main ore types arechalcopyrite, molybdenite, scheelite, hosted in quartz veins and rock fractures, etc. Themain ore body shape is vein and stockwork, which extend along the direction of tectonicgrain.⑵Major element geochemistry shows that the surrounding rock was divided into threegroups: granite, monzogranite and non-granite. The rock sample is a set of peraluminouscalc-alkaline-alkaline series rocks. The characteristics of trace element geochemical showthat large ion lithophile element enrichment and high field strength elements loss insurrounding rock. The standardization of curve spider diagram are W-type right-wing type.Enrichment of ore-forming elements are closely related to hydrothermal activity. Formingmaterial source is not from the surrounding rock, but from the late hydrothermal activity. ⑶The content of REE changes in comparison Large. From the original rocks, alteredrocks, minerals and quartz veins, the content of REE drastically reduced. Normalized REEcurve shows most curves are right-wing europium (Eu) loss type. Potassic altered rockscurve shows weak enrichment for the europium (Eu). LREE fractionation is obvious,,HREE fractionation is not obvious. The REE distribution patterns of ore and quartz veinare obvious differert from the surrounding rock. Ore-forming processes and diageneticprocess have different REE sources. These evidences are proved that the forming materialdoes not come from the surrounding rock, possibly from magmatic-hydrothermal evolutionin the late magmatic activity.â‘·The fluid homogenization temperature range is127.6~451.1℃, an average is235.7℃. The ore-forming fluid temperature has gone through the evolution of central hightemperature (310℃or more)â†'central temperature (160~310℃)â†'low-temperature(160℃), extreme value is located between160~310℃. Fluid related to mineralization atleast two or more, but the most important ore-forming temperature is central temperature(160~310℃). Salinity range2.7to23.2%, an average is13.4%. The metallogenic fluidsalinity is medium salinity.⑸The uniformity of temperature and salinity of the ore-forming fluids has a linearcorrelation. By estimating the metallogenic fluid density is0.9~1.0g/cm3,ore-formingpressure is2.91~3.57MPa, mineralization depth of0.97~1.19km. The evidence shows thatthe deposit is a hypabyssal magmatic hydrothermal deposits.⑹The content of δ34S in deposit’s sulfides is-3.32‰~-0.71‰, with an average is-1.86‰, basically consistent with the recognized porphyry copper sulfide δ34S values (-3‰~+1‰),and its characteristics as same as mantle-derived sulfur. The source of Pbisotope came from intracontinental plate collision orogenic belt, with the crust-mantlemixing characteristics.
Keywords/Search Tags:Jiuling Metallogenic Belt, Lianhuaxin Cu(Mo) Polymetallic Deposit, Geochemical Characteristics, Genesis, Metallogenic Model
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