永平銅多金屬礦床地質(zhì)與地球化學(xué)特征
發(fā)布時間：2018-08-31 12:49
【摘要】：永平銅多金屬礦床位于華南板塊十杭斷裂帶南側(cè),是區(qū)內(nèi)典型的與晚侏羅世二長花崗斑巖類有關(guān)的斑巖-矽卡巖礦床。本文在前人研究工作的基礎(chǔ)上,展開了巖石地球化學(xué)、鋯石U-Pb測年、流體包裹體和穩(wěn)定同位素研究,取得的成果如下:(1)永平礦區(qū)范圍內(nèi)主要存在斑巖型礦化和矽卡巖礦化兩種礦化類型。斑巖型鉬礦化主要發(fā)育在巖體內(nèi)部及巖體與圍巖的接觸帶,形成十字頭鉬礦體;矽卡巖銅礦化主要發(fā)育在巖體外圍的碳酸鹽巖地層的層間破碎帶中,形成天排山銅礦體。鉬礦體和銅礦體緊密相連,兩者的地質(zhì)概況也大致相同。(2)對永平花崗質(zhì)巖體進(jìn)行了主微量、鋯石U-Pb測年等方面的研究。永平花崗質(zhì)巖石定名為二長花崗斑巖,具有高硅、富堿的特點(diǎn),樣品的落點(diǎn)主要位于準(zhǔn)鋁質(zhì)靠近過鋁質(zhì)的區(qū)域,說明為準(zhǔn)鋁質(zhì)-過鋁質(zhì)花崗巖類。Na2O含量變化較大,K2O/Na2O較高,鋁飽和指數(shù)(ASI)為0.97~1.38,整體表現(xiàn)為I-S過渡類型花崗巖的特征。輕稀土元素(LREE)強(qiáng)富集,大離子親石元素(Rb、Ba、U、Th、K、Pb)富集,相當(dāng)于原始地幔的數(shù)百倍,高場強(qiáng)元素(Nb、Ta、Ti)虧損,表明二長花崗斑巖形成于與島弧有關(guān)的構(gòu)造環(huán)境中。鋯石U-Pb定年獲得巖體侵位時代為155.7±2.7Ma,屬于晚侏羅世巖漿活動的產(chǎn)物,研究區(qū)在180~170Ma是大陸弧環(huán)境,160~150Ma為大陸弧和同碰撞構(gòu)造環(huán)境的過渡,之后進(jìn)入碰撞造山階段。(3)流體包裹體研究結(jié)果表明,永平矽卡巖銅礦化與斑巖型鉬礦化成礦流體具有相似的演化特征,都是由高溫向中低溫演化,且是一個自然冷卻的過程,兩者都經(jīng)歷的石英-硫化物階段溫度和鹽度的區(qū)間范圍也具有一定的重合。激光拉曼測試結(jié)果也顯示二者流體包裹體中具有相似的氣相成分(以CO2和H2O為主),成礦流體體系同屬于CO2-H2O-Na Cl體系。(4)硫同位素測試分析結(jié)果顯示,礦石金屬硫化物的δ34S值介于-0.2‰~+1.9‰之間,位于零值附近,這表明成礦物質(zhì)硫源主要來自于深部的巖漿。(5)結(jié)合礦區(qū)地質(zhì)特征,認(rèn)為永平銅多金屬礦床是與晚侏羅世的花崗質(zhì)巖漿關(guān)系密切的巖漿熱液型礦床,十字頭巖體即為巖漿侵位中心,構(gòu)成以斑巖型鉬礦在內(nèi)部,矽卡巖型銅鎢鉛鋅礦在外圍的成礦分帶。十字頭鉬礦體與天排山銅礦體一起構(gòu)成了永平斑巖型-矽卡巖型銅多金屬礦床。
[Abstract]:Yongping copper polymetallic deposit is a typical porphyry skarn deposit related to late Jurassic Erchanggranitic porphyry in the south of the Shihang fault zone of South China plate. On the basis of previous studies, this paper has carried out geochemistry, zircon U-Pb dating, fluid inclusions and stable isotopes. The results are as follows: (1) there are two types of porphyry mineralization and skarn mineralization in Yongping mining area. Porphyry molybdenum mineralization mainly developed in the contact zone between rock mass and surrounding rock to form cross head molybdenum orebody, while skarn copper mineralization mainly developed in the interlayer fracture zone of carbonate strata around the rock mass, forming Tianpaishan copper deposit body. The molybdenum ore body and the copper ore body are closely connected, and their geological profiles are similar. (2) the main trace amount and zircon U-Pb dating of the Yongping granitic rock body have been studied. Yongping granitic rock is named as Erchang granitic porphyry, which has the characteristics of high silicon and rich alkali. The sample's falling point is mainly located in the area of quasi-aluminite near peraluminous, which indicates that the content of quasi-aluminite-peraluminous granitoids has a great change in content of K _ 2O / Na _ 2O, and the content of K _ 2O / Na _ 2O is relatively high. The aluminum saturation index (ASI) is 0.97 ~ 1.38, which is characterized by I-S transition type granite. The (LREE) enrichment of light rare earth elements and the enrichment of large ion lithophile elements (Rb,Ba,U,Th,K,Pb) are hundreds of times as much as those of the primitive mantle. The depletion of high field strength elements (Nb,Ta,Ti) indicates that the Erchang granitic porphyry was formed in a tectonic environment related to island arc. Zircon U-Pb dating obtained an emplacement age of 155.7 鹵2.7 Ma.It is the product of late Jurassic magmatism. The study area is a transition between continental arc and syncollision tectonic environment in 180~170Ma, which is a continental arc environment (160 ~ 150Ma). The results of fluid inclusion study show that the ore-forming fluid of Yongping skarn copper deposit and porphyry molybdenum mineralization have similar evolution characteristics, both of which are from high temperature to middle low temperature, and are a natural cooling process. The range of temperature and salinity in quartz-sulfide stage is also consistent. Laser Raman measurements also show that there are similar gas compositions (mainly CO2 and H2O) in the fluid inclusions, and the ore-forming fluid systems belong to the CO2-H2O-Na Cl system. (4) the sulfur isotope analysis results show that the ore-forming fluid system belongs to the CO2-H2O-Na Cl system. The 未 34S values of ore metal sulfides range from -0.2 鈥，
本文編號：2215036
[Abstract]:Yongping copper polymetallic deposit is a typical porphyry skarn deposit related to late Jurassic Erchanggranitic porphyry in the south of the Shihang fault zone of South China plate. On the basis of previous studies, this paper has carried out geochemistry, zircon U-Pb dating, fluid inclusions and stable isotopes. The results are as follows: (1) there are two types of porphyry mineralization and skarn mineralization in Yongping mining area. Porphyry molybdenum mineralization mainly developed in the contact zone between rock mass and surrounding rock to form cross head molybdenum orebody, while skarn copper mineralization mainly developed in the interlayer fracture zone of carbonate strata around the rock mass, forming Tianpaishan copper deposit body. The molybdenum ore body and the copper ore body are closely connected, and their geological profiles are similar. (2) the main trace amount and zircon U-Pb dating of the Yongping granitic rock body have been studied. Yongping granitic rock is named as Erchang granitic porphyry, which has the characteristics of high silicon and rich alkali. The sample's falling point is mainly located in the area of quasi-aluminite near peraluminous, which indicates that the content of quasi-aluminite-peraluminous granitoids has a great change in content of K _ 2O / Na _ 2O, and the content of K _ 2O / Na _ 2O is relatively high. The aluminum saturation index (ASI) is 0.97 ~ 1.38, which is characterized by I-S transition type granite. The (LREE) enrichment of light rare earth elements and the enrichment of large ion lithophile elements (Rb,Ba,U,Th,K,Pb) are hundreds of times as much as those of the primitive mantle. The depletion of high field strength elements (Nb,Ta,Ti) indicates that the Erchang granitic porphyry was formed in a tectonic environment related to island arc. Zircon U-Pb dating obtained an emplacement age of 155.7 鹵2.7 Ma.It is the product of late Jurassic magmatism. The study area is a transition between continental arc and syncollision tectonic environment in 180~170Ma, which is a continental arc environment (160 ~ 150Ma). The results of fluid inclusion study show that the ore-forming fluid of Yongping skarn copper deposit and porphyry molybdenum mineralization have similar evolution characteristics, both of which are from high temperature to middle low temperature, and are a natural cooling process. The range of temperature and salinity in quartz-sulfide stage is also consistent. Laser Raman measurements also show that there are similar gas compositions (mainly CO2 and H2O) in the fluid inclusions, and the ore-forming fluid systems belong to the CO2-H2O-Na Cl system. (4) the sulfur isotope analysis results show that the ore-forming fluid system belongs to the CO2-H2O-Na Cl system. The 未 34S values of ore metal sulfides range from -0.2 鈥，
本文編號：2215036
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