Genesis of the Jianzhupo Sb-Pb-Zn-Ag deposit and formation of an ore shoot in the Wuxu ore field, Guangxi, South China
Genesis of the Jianzhupo Sb-Pb-Zn-Ag deposit and formation of an ore shoot in the Wuxu ore field, Guangxi, South China
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广西五圩矿田箭竹坡锑铅锌银矿床成因及矿芽形成
DOI：
10.1016/j.oregeorev.2018.09.026
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发表时间：
2018
影响因子：
3.3
通讯作者：
Chen Xilian
中科院分区：
文献类型：
--
作者：
Zhang Jian;Huang Wenting;Liang Huaying;Wu Jing;Chen Xilian
箭竹坡锑铅锌银矿床位于广西大场锡多金属矿带东南部，是吴圩地区最大的矿床，赋存于泥盆系灰岩和泥岩中。该矿床主要由 I 期镁橄榄石-闪锌矿矿脉和 II 期镁镁橄榄石-闪锌矿-方解石-石英 (JSCQ) 矿脉组成。我们利用尖竹坡矿床流体包裹体的均一温度、盐度和 H-O 同位素组成来限制矿床的成因，并确定控制矿芽形成的因素。两个矿化阶段的流体包裹体均含有大量 CO2 和少量沥青、C6H6 和 CH4。矿芽中的流体包裹体产生 120°C–290°C（主要是 250°C–270°C）的均质温度和 3.4–13.6wt% NaCl 当量的盐度。第二阶段矿化的流体包裹体产生 150°C–350°C（主要是 240°C–310°C）的均一温度和 1.4–12.0wt% NaCl 当量的盐度。箭竹坡矿床成矿流体δ18OH2O和δDV-SMOW值分别为4.9‰～9.9‰和-78‰～-111‰，在δDV-SMOWvs上与岩浆水成分接近。 δ18OH2O图。成矿流体中的CO2很可能是由吴圩矿田下方深层矽卡岩化作用产生的，而不是由变质作用、热降解或有机质氧化产生的。含有大量CO2（含少量沥青和C6H6）的成矿流体的H-O同位素组成表明它们来源于与盆地卤水混合的岩浆水。 Ⅰ期成矿流体的δ18OH2O值（4.9‰～6.7‰）低于Ⅱ期成矿流体的δ18OH2O值（7.5‰～9.9‰）。此外，矿芽和JSCQ矿脉的成矿流体在均一温度和盐度之间分别产生强正相关和弱正相关。这种差异表明，岩浆水和盆地卤水之间的快速、大规模混合是控制矿芽形成的关键因素。
The Jianzhupo Sb–Pb–Zn–Ag deposit in the southeastern Dachang Sn–polymetallic ore belt, Guangxi region, South China is the largest deposit in the Wuxu district and is hosted by Devonian limestone and mudstone. The deposit mainly comprises a stage I jamesonite–sphalerite ore shoot and stage II jamesonite–sphalerite–calcite–quartz (JSCQ) veins. We use homogenization temperatures, salinities, and the H–O isotopic compositions of fluid inclusions from the Jianzhupo deposit to constrain the genesis of the deposit and determine factors that controlled the formation of the ore shoot. Fluid inclusions from both stages of mineralization contain large volumes of CO2and minor bitumen, C6H6, and CH4. Fluid inclusions from the ore shoot yield homogenization temperatures of 120 °C–290 °C (mainly 250 °C–270 °C) and salinities of 3.4–13.6 wt% NaCl equiv. Fluid inclusions from the stage II mineralization yield homogenization temperatures of 150 °C–350 °C (mainly 240 °C–310 °C) and salinities of 1.4–12.0 wt% NaCl equiv. Ore-forming fluids of the Jianzhupo deposit yield δ18OH2Oand δDV-SMOWvalues of 4.9‰–9.9‰ and −78‰ to −111‰, respectively, and plot close to the composition of magmatic water on the δDV-SMOWvs. δ18OH2Odiagram. CO2in the ore-forming fluids was likely generated through deep skarnization beneath the Wuxu ore field rather than from metamorphism, thermal degradation, or the oxidization of organic matter. H–O isotopic compositions of ore-forming fluids that contain large volumes of CO2(with minor bitumen and C6H6) indicate that they were derived from magmatic water that was mixed with basin brines. Ore-forming fluids of the stage I ore shoot yield lower δ18OH2Ovalues (4.9‰–6.7‰) than those associated with the stage II mineralization (7.5‰–9.9‰). Moreover, ore-forming fluids of the ore shoot and the JSCQ veins yield strongly and weakly positive correlations between homogenization temperature and salinity, respectively. This difference suggests that rapid and large-scale mixing between magmatic water and basin brines was the key factor that controlled the formation of the ore shoot.