摘要
玲珑金矿位于胶东半岛招-掖成矿带东部,是我国典型的超大型含金石英脉型金矿。成矿过程可划分为早、中、晚三个阶段,金主要在中阶段沉淀。早阶段流体包裹体为纯 CO_2型(L_(CO_2)+V_(CO_2)>90%)和富 CO_2型(10%≤L_(CO_2)+V_(CO_2)≤90%),中阶段为纯 CO_2型、富 CO_2型、富 H_2O 型,晚阶段为水溶液包裹体。从早到晚,包裹体均一温度分别集中在240℃～360℃、220℃～360℃、180℃～260℃和80℃～180℃,盐度分别集中在3.4%～10.4%、3.0%～10.2%、4.0%～14.6%和2.4%～5.0%NaCl eqv;早、中阶段流体盐度随温度降低而升高。中阶段第一世代石英中大量水溶液包裹体和富 CO_2包裹体共生,指示流体强烈沸腾。从早到晚,流体包裹体的变化记录了成矿流体性质和构造环境的演化。早阶段石英中沿 X 型节理发育面型包裹体群,既记录了石英脉遭受的剪切变形事件,又记录了同构造流体作用。而充填于张性裂隙的黄铁矿为主的多金属硫化物-石英组合则表明主成矿期构造环境由压性向张性转化,成矿流体系统减压沸腾、逐步开放,并导致金等成矿物质大量沉淀。结合区域构造演化和成矿时间,认为玲珑金矿成矿系统发育在应力场由挤压向伸展转换的构造背景,流体压力变化滞后于构造应力场变化,流体成分以低盐度、富 CO_2为特征,应属典型的造山型金矿系统。
The Linglong gold deposit is located in the east of Zhao-Ye Metallogenic Zone, which is in the northwest of Jiaodong Peninsula. It is one of the most typical super-large scale gold-bearing quartz vein type deposits. Metallogenic process can be divided into three stages, i.e. the early, meddle and late stages. The composition of fluid inclusion evolved in such a tendency that there are pure CO2 （LCO2 ＋ VCO2 〉90% ） and CO2-rich type （10≤ LCO2 ＋ VCO2 ≤90% ） in the early stage, and pure CO2, CO2-rich and CO2- bearing type （LCO2 ＋ VCO2 〈 10% ） in the middle stage, H2O-rich type in the last stage. Homogenization temperature of fluid inclusion in the three stages was 240℃ - 360℃, 220℃ - 340℃, 180℃ ~ 260℃ and 80℃ ~ 180℃ respectively; and the salinities are 3.4% 10.4% , 3.0% ~ 10.2% , 4.0% ~ 14.6% and 2.4% ~ 5.0% NaCl eqv, respectively. The salinities of fluid increase gradually with the decrease of temperature during the early and middle stages. Main metallizing process of Au took place from 320℃ to 220℃. According to coexisting of CO2-rich and H2O-rich fluid inclusions, a boiling event is presumed in the late middle stage. From the early to the late stage, the tectonic events were recorded in various fluid inclusions. Especially, the inclusions which were sealed along the X-type fissures in the early stage quartz, not only recorded the tectonic events, but also reflected the characteristics of fluid when the events took place. Considering the fact that pyrite-quartz vein filled with extensional cracks during the main stage, it indicates the stress transformed from compressive to extensional condition. Decompressional boiling is assumed to be the main factor resulting in gold precipitation. Fluid pressure data show that their change was hysteretic than tectonic strain＇s. Considering orogenic event that occurred in Jiaodong peninsula, the stress transformed from compressive to extensional condition, and the characteristics low salinity, CO2-rich in ore fluid, Linglong gold deposit is assured a typic orogenic gold deposit.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第9期2207-2216,共10页
Acta Petrologica Sinica
基金
国家973项目2006CB403501课题
自然科学基金项目(编号40672059)
关键词
胶东
玲珑金矿
造山型金矿
面型包裹体群
成矿流体
Jiaodong peninsula, Linglong gold deposit, Orogenic gold deposit, Fluid inclusion plane, Ore-forming fluid
