本文選題：三江成礦帶　切入點(diǎn)：尕龍格瑪　出處：《地球科學(xué)》2017年06期

【摘要】：為確定中國三江成礦帶北段尕龍格瑪VMS(volcanogenic massive sulfide)型礦床的成礦物理化學(xué)條件、成礦物質(zhì)來源、成礦流體來源,探討成礦機(jī)制,對礦體特征、流體包裹體顯微測溫和激光拉曼光譜分析以及S、Pb、H、O同位素進(jìn)行了系統(tǒng)研究.礦體賦存于晚三疊世巴塘群英安質(zhì)火山巖中,具有VMS型礦床的雙層結(jié)構(gòu),由下部熱液流體補(bǔ)給通道相的脈狀-網(wǎng)脈狀礦化系統(tǒng)和上部海底盆地鹵水池噴氣-化學(xué)沉積系統(tǒng)組成.通道相中流體包裹體可分為富氣相包裹體和水溶液包裹體,均一溫度為175.6~263.3℃,鹽度為1.05%~6.29%NaCl eqv.,密度為0.820~0.935g/cm3,激光拉曼光譜分析包裹體氣相成分為H2O、CO2和少量N2;沉積相重晶石中僅發(fā)育水溶液包裹體,均一溫度為105.2~157.1℃,鹽度為0.18%~5.55%NaCl eqv.,密度為0.735~1.173g/cm3,顯示了流體由通道相向沉積相溫度顯著降低,鹽度保持不變,密度變大的趨勢,與典型VMS型礦床流體特征相似.氫氧同位素(δ18 OH2O:0.25‰~1.75‰,δD:-103.2‰~-65.3‰)研究表明,成礦流體主要來源于巖漿水和海水的混合.綜合分析前人硫同位素研究結(jié)果(δ34 S:1.13‰~2.45‰,12.36‰~12.37‰)及本次獲得硫同位素結(jié)果(δ34 S:-22.9‰~-14.7‰)表明硫來源于巖漿和細(xì)菌還原的海水硫酸鹽或基底巖石.硫化物方鉛礦的206 Pb/204 Pb、207 Pb/204 Pb和208Pb/204Pb分別為18.449~18.519、15.699~15.777和38.875~39.141,具有高放射性鉛的特征,μ值為9.65~9.80,結(jié)果顯示Pb等成礦物質(zhì)主要來自于上地殼,并有巖漿物質(zhì)參與成礦.成礦流體與海水的混合作用是尕龍格瑪?shù)V床形成的主要機(jī)制.
[Abstract]:In order to determine the ore-forming physicochemical conditions, ore-forming material sources, ore-forming fluid sources, metallogenic mechanism and ore-body characteristics of Galonggma VMS(volcanogenic massive sulfidetype deposits in the northern part of Sanjiang metallogenic belt, the ore-forming physical and chemical conditions, ore-forming material sources, ore-forming fluid sources, ore-forming mechanism andThe microthermometry of fluid inclusions, laser Raman spectroscopy, and the S _ (Pb) H _ (O) isotopes have been systematically studied.The orebody occurs in the late Triassic Batang Group amphibious volcanic rocks and has the double layer structure of VMS type deposit, which is composed of the vein and network vein mineralization system of the lower hydrothermal fluid supply channel phase and the upper seabed basin brine pool exhalation and chemical deposition system.The fluid inclusions in channel phase can be divided into gas-rich inclusions and aqueous inclusions. The homogenization temperature is 175.6C 263.3 鈩，

本文編號：1719364