Evidence of fluid inclusions for two stages of fluid boiling in the formation of the giant Shapinggou porphyry Mo deposit, Dabie Orogen, Central China
Evidence of fluid inclusions for two stages of fluid boiling in the formation of the giant Shapinggou porphyry Mo deposit, Dabie Orogen, Central China
复制标题
华中大别造山带沙坪沟巨型斑岩钼矿床形成过程中两阶段流体沸腾的流体包裹体证据
DOI：
10.1016/j.oregeorev.2014.09.017
复制
发表时间：
2015-03
影响因子：
3.3
通讯作者：
Xu Ying-Feng
中科院分区：
文献类型：
--
作者：
Ni Pei;Wang Guo-Guang;Yu Wen;Chen Hui;Jiang Lai-Li;Wang Bo-Hua;Zhang Huai-Dong;Xu Ying-Feng
大别造山带沙坪沟斑岩钼存款矿床是亚洲最大的钼矿床之一。沙坪沟热液蚀变成矿作用可分为四个阶段，第1阶段为硅化强烈的贫矿石英脉，第2阶段为钾化的石英-橄榄岩脉，第3阶段为千枚岩化的石英-多金属硫化物脉，第4阶段为弱青岩化的贫矿石英±方解石±黄铁矿脉。热液石英主要含有三种类型的流体包裹体，即富液相的两相包裹体（I型）、富气的含CO2的两相或三相包裹体（II型）和含石盐的（III型）。后两种类型的流体包裹体在第1和第4阶段中不存在。第一阶段变质带中的I型包裹体均质温度为340 ~ 550 ℃，盐度为7.9- 16.9wt.% NaCl当量。第二阶段钾质带中的II型包裹体和共存的III型包裹体的均一温度分别为240-440 °C和240-450 °C，盐度分别为34.1-50.9和0.1- 7.4wt.% NaCl当量。第三阶段（phyllic zone）中的II型和共存的III型包裹体显示均一温度分别为250-345 °C和220-315 °C，盐度分别为0.2-6.5和32.9- 39.3wt.% NaCl当量。第四期橄榄岩化带的I型包裹体均一温度为170 ~ 330 ℃，盐度低于6.5wt.% NaCl当量。富CO2和共存的含石盐流体包裹体组合在钾质和千枚岩带突出了强烈的流体沸腾的NaCl-CO2-H2O系统在深部环境（高达2.3 kbar）的巨型斑岩钼矿化的意义。氢、氧同位素组成表明成矿流体由岩浆成因逐渐演化为大气降水成因。硫、铅同位素表明，沙坪沟成矿物质为岩浆成因。榴辉岩的Re-Os定年结果表明，榴辉岩的187 Re/187 Os等时线年龄为112.7 ± 1.8Ma，属后碰撞环境。
The Shapinggou porphyry Mo deposit, one of the largest Mo deposits in Asia, is located in the Dabie Orogen, Central China. Hydrothermal alteration and mineralization at Shapinggou can be divided into four stages, i.e., stage 1 ore-barren quartz veins with intense silicification, followed by stage 2 quartz-molybdenite veins associated with potassic alteration, stage 3 quartz-polymetallic sulfide veins related to phyllic alteration, and stage 4 ore-barren quartz ± calcite ± pyrite veins with weak propylitization. Hydrothermal quartz mainly contains three types of fluid inclusions, namely, two-phase liquid-rich (type I), two- or three-phase gas-rich CO2-bearing (type II) and halite-bearing (type III) inclusions. The last two types of fluid inclusions are absent in stages 1 and 4. Type I inclusions in the silicic zone (stage 1) display homogenization temperatures of 340 to 550 °C, with salinities of 7.9–16.9 wt.% NaCl equivalent. Type II and coexisting type III inclusions in the potassic zone (stage 2), which hosts the main Mo orebodies, have homogenization temperatures of 240–440 °C and 240–450 °C, with salinities of 34.1–50.9 and 0.1–7.4 wt.% NaCl equivalent, respectively. Type II and coexisting type III inclusions in the phyllic zone (stage 3) display homogenization temperatures of 250–345 °C and 220–315 °C, with salinities of 0.2–6.5 and 32.9–39.3 wt.% NaCl equivalent, respectively. Type I inclusions in the propylitization zone (stage 4) display homogenization temperatures of 170 to 330 °C, with salinities lower than 6.5 wt.% NaCl equivalent. The abundant CO2-rich and coexisting halite-bearing fluid inclusion assemblages in the potassic and phyllic zones highlight the significance of intensive fluid boiling of a NaCl–CO2–H2O system in deep environments (up to 2.3 kbar) for giant porphyry Mo mineralization. Hydrogen and oxygen isotopic compositions indicate that ore-fluids were gradually evolved from magmatic to meteoric in origin. Sulfur and lead isotopes suggest that the ore-forming materials at Shapinggou are magmatic in origin. Re–Os dating of molybdenite gives a well-defined187Re/187Os isochron with an age of 112.7 ± 1.8 Ma, suggesting a post-collisional setting.
登录
查看更多内容
影响因子：
4.8
作者：
Yang Ze
通讯作者：
Yang Ze
影响因子：
4.8
作者：
C. McEwan;A. Fallick;C. Rice
通讯作者：
C. McEwan;A. Fallick;C. Rice
影响因子：
2.9
作者：
R. Zartman;B. Doe
通讯作者：
R. Zartman;B. Doe
影响因子：
5.8
作者：
J. Cline;R. Bodnar
通讯作者：
J. Cline;R. Bodnar
影响因子：
4.8
作者：
Zhang Huai
通讯作者：
Zhang Huai