大坪金矿床是赋存于闪长岩体中的含金多金属硫化物热液石英脉型金矿,矿体呈脉状,三家河断裂、小新街断裂、小寨–金平断裂控制着矿区地层岩性。成矿过程可划分为3个阶段:1) 白钨矿–石英脉阶段;2) 团块状多金属硫化物阶段;3) 碳酸盐–石英脉阶段。石英脉中流体包裹体分为富液相CO2包裹体、富气相CO2包裹体、CO2型包裹体,以CO2-H2O包裹体为主。CO2-H2O包裹体的完全均一温度236.5℃~379.2℃,盐度为1.74~18.63 wt% NaCl,成矿流体具有中–高温、中–低盐度、富含CO2并且含有少量N2的特征,属于CO2-H2O-NaCl ± N2体系,且成矿流体的温度逐渐降低。成矿流体来源复杂,为深源的壳幔混合流体,即成矿流体的主体为深源的流体,后期有浅部的混合流体加入。大坪金矿矿区北部属于造山型金矿,南部属于浅成低温热液型金矿。The Daping gold deposit is a hydrothermal quartz vein-type gold deposit containing gold-bearing polymetallic sulfides hosted in a diorite intrusion. The ore bodies occur as veins, with the regional stratigraphy and lithology controlled by the Sanjiahe Fault, Xiaoxinjie Fault, and Xiaozhai-Jinping Fault. The mineralization process can be divided into three stages: 1) Scheelite-quartz vein stage, 2) Massive polymetallic sulfide stage, and 3) Carbonate-quartz vein stage. Fluid inclusions in the quartz veins can be classified into liquid-rich CO2 inclusions, vapor-rich CO2 inclusions, and CO2-H2O inclusions, with CO2-H2O inclusions being predominant. The homogenization temperatures of CO2-H2O inclusions range from 236.5˚C to 379.2˚C, and their salinities range from 1.74 to 18.63 wt% NaCl equivalent. The ore-forming fluids are characterized by medium-to-high temperatures, medium-to-low salinities, CO2 enrichment, and the presence of small amounts of N2, belonging to the CO2-H2O-NaCl ± N2 system. The temperature of the ore-forming fluids gradually decreased over time. The ore-forming fluids have a complex
南芬BIF(Banded iron formation,条带状含铁建造)是鞍山—本溪地区重要的铁矿床之一,呈层状、似层状赋存于新太古代鞍山群茨沟岩组含铁岩段中,自下而上由Fe1、Fe2和Fe33个铁矿体组成。矿石类型主要为磁铁石英岩、透闪磁铁石英岩、赤铁磁铁石英岩和赤铁石英岩。根据矿物组合和共生序列,成矿演化期次可分为5期:沉积期、成岩期、区域变质变形期、热液改造期、表生氧化期。为了查明南芬BIF的成矿流体特征,本文在对矿床地质特征、矿物共生关系进行了野外调查和室内镜下研究的基础上,利用岩相学、显微测温等技术手段,对该矿床中不同类型磁铁石英岩中的石英开展了详细的流体包裹体特征研究。流体包裹体岩相学结果显示,南芬铁矿主要发育3类包裹体,分为Ⅰ类次生包裹体、Ⅱ类气液两相原生包裹体(Ⅱa类液相包裹体、Ⅱb类气体包裹体)和Ⅲ类含液相CO_(2)三相包裹体。流体包裹体显微测温结果显示,南芬铁矿绿帘—角闪岩相变质作用峰期发育Ⅲ类和Ⅱb类包裹体,峰期变质流体均一温度为283.2~423.5℃,盐度范围为3.39%~9.47%NaCleqv,显示高温低盐度特征;而绿帘—角闪岩相变质作用峰期后发育Ⅰ类、Ⅱa类包裹体,均一温度范围为191.3~308.8℃,盐度范围为2.24%~10.61%NaCleqv,均一温度及盐度范围均较宽。综合流体包裹体特征和其他地质证据,认为区域变质峰后阶段变质流体具有多期性的特点。
