本文關鍵詞： 流體包裹體 流體演化 銅多金屬礦床 湖南寶山　出處：《巖石學報》2017年03期 　論文類型：期刊論文

【摘要】：寶山礦床處于NE向欽杭成礦帶與EW向南嶺成礦帶的結合部位,是湘南地區(qū)最大的銅多金屬礦床,成礦斑巖主要為花崗閃長斑巖,其中銅鉬礦體主要分布于花崗質巖體與碳酸鹽巖接觸帶的矽卡巖中,鉛鋅礦體則分布于斷裂破碎帶和石炭系的層間裂隙帶中。本文以寶山銅多金屬礦床為研究對象,在詳細野外調查的基礎上,系統(tǒng)開展了鏡下觀察、流體包裹體顯微測溫、激光拉曼分析以及H-O同位素分析,進而對寶山礦床的成礦流體演化進行了初步研究,獲得了如下認識:(1)該礦床成礦演化過程可分為矽卡巖階段、退化蝕變階段、金屬硫化物階段及螢石-方解石脈階段;(2)包裹體類型以富液相包裹體為主,成礦流體主要為H_2O-NaCl體系,含少量的CO_2,偶見含子晶包裹體;(3)矽卡巖階段流體包裹體均一溫度分布在430~550℃,主要集中在550℃以上,鹽度范圍為13.4%~21.98%NaC leqv;退化蝕變階段的均一溫度范圍為211.8~395℃,在260~320℃和360~395℃出現(xiàn)兩個峰值,鹽度范圍為3.71%~19.53%NaCleqv,該階段圍壓由靜巖壓力向靜水壓力轉變;金屬硫化物階段均一溫度分布于156.7~323.1℃,主要為190~240℃,鹽度范圍為3.71%~19.84%NaC leqv;螢石-方解石脈階段中的包裹體均一溫度為100~266.5℃,主要集中于145~180℃,鹽度分布在0.71%~18.3%NaC leqv。寶山礦床成礦壓力介于23.8~169.9Mpa之間,利用靜巖壓力-靜水壓力梯度可得寶山礦床成礦深度約為2.25~6.29km,主要為4~6km;(4)退化蝕變階段流體的37‰~7.47‰之間,δD_(H_2O)值介于3. 64‰;金屬硫化物階段和螢石-方解石脈階段的δ~(18)O_(H_2O)值為-70‰~-δ~(18)O_(H_2O)值介于0.33‰~5.28‰之間,表明有大量的大氣降水混入。因此,成礦流體從早階段到晚階段,由巖漿熱液演變?yōu)榇髿饨邓?流體混合作用可能是礦質沉淀的主要機制。寶山銅多金屬礦床是早期高溫中高鹽度流體向低溫低鹽度流體演化過程中形成的。
[Abstract]:Baoshan deposit, which is the largest copper polymetallic deposit in southern Hunan, is located in the combination of NE Xiang Qinhang metallogenic belt and EW Nanling metallogenic belt. The ore-forming porphyry is mainly granodiorite porphyry. The copper-molybdenum ore body is mainly distributed in skarn in the contact zone between granitic and carbonate rocks, while the lead-zinc ore body is distributed in the fracture zone and the interlayer fissure zone of Carboniferous. In this paper, the Baoshan copper polymetallic deposit is taken as the research object. On the basis of detailed field investigation, the microscopic temperature measurement of fluid inclusions, laser Raman analysis and H-O isotope analysis have been carried out systematically, and the evolution of ore-forming fluids in Baoshan deposit has been preliminarily studied. The ore-forming evolution of the deposit can be divided into skarn stage, degenerative alteration stage, metal sulphide stage and fluorite-calcite vein stage. The inclusions are mainly liquid-rich inclusions, and the ore-forming fluids are mainly H _ 2O-NaCl systems. The homogeneous temperature of fluid inclusions in skarn stage is 430 ~ 550 鈩，

本文編號：1539128