Fluid inclusion characteristics of intrusion-related gold mineralization, Tombstone–Tungsten magmatic belt, Yukon Territory, Canada
Fluid inclusion characteristics of intrusion-related gold mineralization, Tombstone–Tungsten magmatic belt, Yukon Territory, Canada
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DOI：
10.1007/s001260100189
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发表时间：
2001-09
影响因子：
4.8
通讯作者：
T. Baker;J. R. Lang
中科院分区：
文献类型：
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作者：
T. Baker;J. R. Lang
在育空地区中白垩世墓石-钨岩浆带的许多深成和矿体中，常见的侵入岩、低硫化物、片状脉体系统是重要的金矿化的寄主。翡翠湖、都柏林峡谷、白钨穹隆、麦克湖和麦克洞五个系统的流体包裹体特征制约着成脉流体成分、地层温度和压力、热液作用和潜在的流体来源。矿脉中含有多种流体包裹体类型。普遍存在的1A型和1B型包裹体为低盐度(1a：xNacl<；0.02；1B：xNacl<；0.03)、富CO2(1A：xCO2=0.18-1.00；1B：xCO2=0.02-0.33)。激光拉曼光谱研究表明，1A型和1B型包裹体通常含有少量CH4(XCH4和Lt；0.09)和N2(XN2和Lt；0.12)。第二类包裹体为富H2O(XH2O=0.94-0.99)、中低盐度(XNaC l=0.01-0.06)的包裹体，在翡翠湖和都柏林峡谷普遍存在，并有局部性的3A型盐岩包裹体(XNacl=0.12-0.16)。这两种包裹体类型都发生在富二氧化碳包裹体的形成时间之后。Mike Lake岩体中的片状脉体含有1A型、3A型和3B型(岩盐+钾盐)包裹体。所有研究系统中均一的A型包裹体在208-362℃之间，1B型包裹体在205-329℃之间，2型包裹体在154-261℃之间。3A和3B型包裹体均一化在217-355℃之间。富含二氧化碳和盐分的流体的主要岩浆来源是有利的，圈闭压力的变化(<；1 kbar在Mike Lake，>；1 kbar在翡翠湖和都柏林峡谷，和>；2 kbar在Macung和Scheite Dome)，可能控制流体的成分和演化。多种流体作用可能导致了金的沉淀，包括不混溶和/或岩浆流体的释放。
Intrusion-hosted, low sulfide, sheeted vein systems are common within many plutons and stocks of the middle Cretaceous Tombstone–Tungsten magmatic belt, Yukon Territory, and host significant gold mineralization. Fluid inclusion characteristics of five such systems, namely Emerald Lake, Dublin Gulch, Scheelite Dome, Mike Lake, and MacTung, constrain the vein-forming fluid composition, formation temperatures and pressures, hydrothermal fluid processes, and potential fluid sources. The veins contain a wide range of fluid inclusion types. Ubiquitous type 1A and 1B inclusions are low salinity (1A: XNaCl<0.02; 1B: XNaCl<0.03), CO2-rich (1A: XCO2=0.18–1.00; 1B: XCO2=0.02–0.33). Laser Raman studies indicate that type 1A and 1B inclusions commonly contain minor CH4(XCH4<0.09) and N2(XN2<0.12). Type 2 inclusions are H2O-rich (XH2O=0.94–0.99), of low to moderate salinity (XNaCl=0.01–0.06), and were common at Emerald Lake and Dublin Gulch, in addition to localized type 3A halite-bearing inclusions (XNaCl=0.12–0.16). Both inclusion types post-dated the CO2-rich inclusions. Sheeted veins in the Mike Lake pluton contained coexisting type 1A and 3A and 3B (halite + sylvite) inclusions. Type 1A inclusions in all studied systems homogenized between 208 and 362 °C, type 1B ranged between 205 and 329 °C, and type 2 between 154 and 261 °C. Type 3A and 3B inclusions homogenized between 217 and 355 °C. A predominantly magmatic source for both CO2-rich and saline H2O-rich fluids is favored, with variations in trapping pressure (<1 kbar at Mike Lake, >1 kbar at Emerald Lake and Dublin Gulch, and >2 kbar at MacTung and Scheelite Dome) that potentially control fluid composition and evolution. A variety of fluid processes may have been responsible for gold precipitation including immiscibility and/or release of an evolving magmatic fluid.