Characteristics Of Mineralization Mineralogy In The Great Depth Of Jinqingding Gold Deposit, Jiao Dong Region

Jinqingding gold deposit located in the middle of Muping-Rushang ore forming belt is the biggest quartz-vein type gold deposit in China. At first, this paper detailly discussed the geological and hydrothermal alteration characteristics. According to the study of altered mineral and isotope characteristics together with the fluid inclusion of quartz and water-rock interaction process research, we aimed to identify the ore-forming age, resource of ore-forming materials and fluids, physical and chemical conditions of the fluids and hydrothermal mineralization, and prospecting for mineralization of ore-body II in the deep.The deposit hydrothermal alteration is characteristics of multi-type, multi-stage and from high to low temperature. The main types of alteration include K-feldspar alteration, sericite quartz alteration, pyrite sericite quartz alteration. The pre-mineralization is marked of massive K-feldspar alteration, while pyrite sericite quartz alteration is accompanying with the start of minerals precipitation.Chemical composition and numerous pores with a large number of hematite barite and rutile containing of the K-feldspar as the product of fluid-rock interaction indicate the fluids are full of K, Na, Si composition and highly oxidized in the early K-feldspar alteration stage; Based on two-feldspar thermometer and the potassium feldspar structure states thermometer, we estimate the pegmatite likely and K-feldspar altered granite forming at the temperature between 433-482℃,320-419℃ respectively. Altered chlorite include vermicular-chlorite, iron-magnesium-chlorite and chamosite, its chemical composition analysis showed the fluids rich in the Si composition, the Si, Fe/(Fe+Mg) values of altered chlorite increased gradually, and metallogenic environment tend to low oxygen fugacity reducing environment, as the process of the wall-rock alteration and mineralization; the secondary chlorite minerals thermometer of the K-feldspar, pyrite-sericite-quartz alteration rocks demonstrated they formation temperature are almost between 337-380℃,250-340℃ respectively.Argon isotope test of altered lumpy K-feldspar shows its formed at the age of 118.7±1.2 Ma, and ore-forming hydrothermal alteration event has no business to the emplacement of Kunyushan monzogranite directly. Carbon- oxygen isotope testing demonstrated δ13Cv-PDB‰ ranges from-1.3 to -4.9,δ18OV-SMOW‰ ranges from 7.5 to 11.7 which suggested that the source of carbon material comes from the mantle and primary magma; δ18OV-SMOWto δ13Cv-PDB map reveals the evolution of carbon and oxygen isotopes related to the process of the high temperature magma contaminating and seawater penetration.The fluids are potassium-rich, high-temperature, alkaline and high oxygen fugacity at the K-feldspar alteration stage, to the pyrite-sericite-quartz alteration stage the fluids environment turns to medium-high temperature, neutral-acidic and deoxidization, minerals began uninstall, precipitation and enrichment. Water-rock reactions, fluid immiscibility and the escape of CO2, changes of physical and chemical parameters is the main reason for gold mineralization.Mineralogy mapping of quartz mineral typomorphic about zonal structure and thermoelectricity demonstrate:although ore-body Ⅱ in deep bellow -785 meter will mineralization to some degree, while the ore-body basically closed down the extension.