本文選題：巖漿期后熱液礦床 + 板塊內(nèi)部拉張環(huán)境　； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：唐杖子金多金屬礦床位于冀東寬城縣南東約17km處,大地構(gòu)造位置處于華北克拉通北緣中段,燕山褶斷帶。本次工作主要目的是研究成巖—成礦相互關(guān)系、流體來源和成礦物質(zhì)來源,探討成礦作用機(jī)制。通過礦區(qū)的金屬硫化物電子探針分析、巖漿巖鋯石U-Pb年齡及Hf同位素組成、全巖地球化學(xué)分析、流體包裹體顯微測溫、流體包裹體的H-O同位素組成和金屬硫化物的S及He-Ar同位素組成的研究,取得了以下認(rèn)識:根據(jù)礦體地質(zhì)特征、礦石礦物組合、脈體穿插關(guān)系,將整個(gè)礦床成礦過程劃分成了2個(gè)成礦亞期,6個(gè)成礦階段。輝鉬礦成礦亞期分3個(gè)階段:鉀長石階段、輝鉬礦化階段、黃鐵礦—碳酸鹽階段。金多金屬成礦亞期分3個(gè)階段:黃鐵礦—石英階段、金多金屬礦化階段、石英—碳酸鹽階段。金主要賦存在煙灰色石英粗脈中,或與黃鐵礦、黃銅礦、閃鋅礦、方鉛礦等金屬硫化物伴生。金屬硫化物電子探針分析結(jié)果表明,金主要賦存在金多金屬硫化階段的黃鐵礦中。銀主要與方鉛礦、銀黝銅礦伴生,且主要賦存在銀黝銅礦中。采自370m平硐中段的花崗斑巖鋯石U-Pb年齡分別為161.23±0.65Ma(A組)、173.0±5.5Ma(B組)。B組年齡代表成巖年齡,A組鋯石可能是到成巖期后熱液活動影響,丟失了放射性成因Pb,從而得到較小年齡�；◢彴邘r鋯石測年結(jié)果限定了唐杖子金礦的成礦時(shí)間下限為173.0±5.5Ma。結(jié)合前人對該區(qū)域的構(gòu)造背景研究和花崗斑巖、輝綠巖的地球化學(xué)分析結(jié)果,認(rèn)為成礦構(gòu)造背景應(yīng)為板塊內(nèi)部的局部拉張環(huán)境。不同成礦階段流體包裹體的顯微觀察、測溫結(jié)果表明,成礦流體屬于中溫、中低鹽度的H2O-CO2-Na Cl體系。測得具有代表性的金多金屬硫化物階段的流體包裹體均一溫度范圍在143.7℃~320℃,峰值介于170℃~240℃,鹽度為4.96%~11.7%,密度為0.96 g/cm3~0.81 g/cm3。H、O同位素組成表明,成礦流體主要來源于巖漿水,并有少量大氣水的加入。金屬硫化物的S、He-Ar同位素組成表明,礦物主要來源于地殼。
[Abstract]:The Tangchangzi gold polymetallic deposit is located at 17km in the south east of Kuancheng County in eastern Hebei Province. The tectonic position is in the middle section of the northern margin of North China Craton and the Yanshanian fold fault belt. The main purpose of this work is to study the relationship between diagenesis and metallogenesis, the source of fluid and ore-forming material, and the mechanism of mineralization. Through electron probe analysis of metallic sulfides, zircon U-Pb age and HF isotopic composition of magmatic rocks, whole rock geochemistry analysis, microthermometry of fluid inclusions, The H-O isotopic compositions of fluid inclusions and the S and He-Ar isotopic compositions of metallic sulphides have been studied. The metallogenic process of the deposit is divided into two metallogenic substages and six metallogenic stages. The sub-stage of molybdenum mineralization is divided into three stages: potassium feldspar stage, molybdenum mineralization stage and pyrite carbonate stage. The gold polymetallic metallogenic substage is divided into three stages: pyrite-quartz stage, gold polymetallic mineralization stage, quartz-carbonate stage. Gold mainly occurs in the hayotinite quartz veins, or with pyrite, chalcopyrite, sphalerite, galena and other metal sulfides. The results of electron probe analysis of metallic sulphide indicate that gold mainly occurs in pyrite during the sulfidation stage. Silver is mainly associated with galena, tetrahedrite and mainly occurs in silver tetrahedrite. The U-Pb age of granitic porphyry zircon collected from the middle part of 370m adit is 161.23 鹵0.65Ma(A group (173.0 鹵5.5Ma(B group). The age of group B represents the diagenetic age group A zircon may be affected by hydrothermal activity after diagenesis, and the radiogenic Pb is lost, thus the younger age can be obtained. The zircon dating results of granitic porphyry indicate that the lower limit of metallogenic time of Tangzhang gold deposit is 173.0 鹵5.5 Ma. Based on the previous studies on the tectonic setting of the area and the geochemical analysis of granitic porphyry and diabase, it is concluded that the metallogenic tectonic setting should be a local extensional environment within the plate. The microscopical observation of fluid inclusions in different metallogenic stages shows that the ore-forming fluid belongs to H2O-CO2-Na Cl system with medium temperature and low salinity. The homogenization temperature range of fluid inclusions in the representative gold polymetallic sulphide stage is 143.7 鈩，

本文編號：1785691