Font Size: a A A

Tectonic Physicochemistry Study On Regional Fluid In East Shandong Area During Mesozoic Gold Mineralization

Posted on:2004-02-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:L XiaFull Text:PDF
GTID:1100360218956741Subject:Structural geology
Abstract/Summary:PDF Full Text Request
It is very popular to study the regional metallogenic fluid for the earth science; at present, however,there aren't any constructive methods and standards in the fields about regional fluid distribution,transportation and the relationship to minerals. This dissertation, under the guidance of TectonicPhysicochemistry, sponsored by Mr. LüGuxian Researcher, selects the east Shandong Peninsula as theregional structrure and metallogenic fluid research target with the following achievements attained:Firstly, by means of a systematic summary of forerunner's research results, this dissertation illustratesthe development characteristics of three stages of Jiaodong gold mineralization area and puts forwardulteriorly that gold mineralization in the east Shandong Peninsula undergoes threes tages, the formationstage of Archean-Proterozoic greenstone landmass, the stable Paleozoic uplift stage and the strongactivation-reconstruction stage of Mesozoic greenstone belt and points out that a strong sinister shear-extension, dextral shear-extention locally, by Tanlu Fault Belt in Mesozoic resulted in a large-scalelithosphere thinning, a major mechanism for gold mineralization in the east Shandong Peninsula.Secondly, based on the data in this paper and large quantity of existing data, three advantageousconditions for regional fluid study are studied and summarized systematically, that is, a relativelyconcentalized mineralization age, a relatively stable structructural stress field during goldmineralization and a possible same metallogenic fluid.Thirdly, based on the field work, indoor measurements and computation, the rock transformation ratioand and dynamic recrystalline quartz grains are measured and so the sturtural differential stress on acplane and bc plane,σ1,σ2,σ3, and the additional hydrostatic pressure produced by structure arecalculated with the result that the the additional hydrostatic pressure produced by structure lies between800~1300×105Pa and, from west to east, tends to decrease, indicating in the rough that theregional fluid flows from west to east.Forthly, a deltailed study on temperature, pressure, salinity and components of fluid inclusions among21 gold depsoits in the east Shandong Peninsula means that the fluid inclusions are mainly CO2-NaCl-H2O type with a high content of CO2, although there is obvious difference among all districts, meaningthat there are different regional fluid resources.Fifthly, small-scaled isoline maps about the tectonophysicochemical parameters of gold deposits arecompiled to mean that: [1] among concentration parameters, Ca2+, Mg2+, F-, Cl- reflect the regionalstructure and SO42-, Na+, K+ are relative to gold mineralization; [2] among gas parameters, H2, CO2,H2O reflect the regional structure and CH4, CO are relative to gold mineralization; [3] among ratioparameters, Na+/Ca2+, Ca2+/Mg2+, F-/Cl-, CO2/H2O reflect the regional structure and Na+/K+, R arerelative to gold mineralization; [4] among condition parameters, most gold deposits are located in thetransition zone between high pressure and low pressure and the temperature is obviously relative togranite bodies.Sixthly, at consideration of the other metallic deposits in the east Shandong Peninsula, a fuzzy groupinganalysis about the liquidphase components, vapour components and ratio was made with 5 groupsclassified: (1) represented by Sanshandao, Jiaojia and Yaishang gold depsoits; (2) represented byLingshangou, Jinchiling gold deposits and Shilipu silver depsoit; (3) represented by Majiayao, Liukouand Heilangou gold deposits; (4) represented by Jinqingding, Denggezhuang and Rushan gold deposits;(5) represented by the Western Fanjiabu gold deposit. The categories above, basically subject to thefaults, have unique metallic assemblages, indicating a metallogenic fluid activation-transportation-deposition rule dominated by faults.Finally, at the base of the forrunners' results, the sulfur isotope distribution and its fractionation instrata, granites, veins and gold deposits are systemactically studied. Indicated by the regional sulfurisotope isoline map, at level, from west to east, the sulfur isotope is characterized by the alternative 5high value belts and 5 low value belts, which is mainly controlled by the size and intensity of faults;west to east,δ34S tends to become lower, indicating a higher uplift in the west. Normally, quartz-vein-type gold deposits (Linglong-type) have a lowerδ34S than altered-rock-type gold deposits (Jiaojia-type)do.
Keywords/Search Tags:Regional metallogenic fluid, Tectonic physicochemistry, Structural stress field, Sulfur isotope, Gold deposits, Mesozoic, East Shandong Area
PDF Full Text Request
Related items