Geology and geochemistry of the Qiaoxiahala Fe-Cu-Au deposit, Junggar region, northwest China
Geology and geochemistry of the Qiaoxiahala Fe-Cu-Au deposit, Junggar region, northwest China
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DOI：
10.1016/j.oregeorev.2013.08.003
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发表时间：
2014-03
影响因子：
3.3
通讯作者：
Qiangliang Li;Zhixin Zhang;Xinxia Geng;Chao Li;Feng Liu;F. Chai;Fuquan Yang
中科院分区：
文献类型：
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作者：
Qiangliang Li;Zhixin Zhang;Xinxia Geng;Chao Li;Feng Liu;F. Chai;Fuquan Yang
中国准噶尔地体北缘富蕴县乔夏哈拉铁铜金矿床赋存于北塔山组中泥盆统凝灰岩砂岩、大理岩、凝灰岩、玄武岩和安山岩中。铜、铁矿体多呈层状、豆荚状或透镜状，与矿区闪长斑岩脉具有时空相关性。矿床与绿帘石、绿泥石、石榴石、透辉石、钾长石、石英、碳酸盐围岩蚀变有关。根据野外证据和岩相分析，可划分为三个成矿阶段：(1)进化夕卡岩阶段；(2)与铁矿化发育有关的退化期；(3)与铜、金成矿有关的石英-硫化物-碳酸盐阶段。石英和方解石中的流体包裹体中存在H2O-氯化钠和H2O-CO2-(±1CH4/N_2)-氯化钠流体。这些流体的峰值温度为200-320℃，盐度为1.23-13.72wt.%的氯化钠当量。石英和方解石的稳定同位素分析得出−为141‰至−为93‰为δD，‰为8.1‰至15.8δ为18OSMOW，−为0.7‰至9.6‰为δ180流体，−为3.9‰至−为2.7‰为δ13CPDB，表明成矿流体主要为岩浆流体，并有一定的大气降水贡献。黄铁矿和黄铜矿的δ34S值在−=4.3‰~2.9‰之间，表明矿床中的硫可能来自深部岩浆。闪长斑岩的锆石U-Pb定年(206Pb/238U)加权平均年龄为377.6±21.4 Ma，辉钼矿的Re-Os等时线年龄为375.2±22.6 Ma。这些年代学数据表明，与成矿有关的闪长斑岩侵位于晚泥盆世，与乔夏哈拉铁铜金矿床的成矿时代相吻合。地质和地球化学证据表明，乔夏哈拉铁铜金矿床与闪长斑岩晚期岩浆热液活动有关，与IOCG矿床有许多相似之处。
The Qiaoxiahala Fe–Cu–Au deposit located in Fuyun County at the northern margin of Junggar Terrane in China is hosted by Middle Devonian tuffaceous sandstones, marbles, tuffs, basalts, and andesites of the Beitashan Formation. The Cu and most Fe orebodies are stratiform, podiform, or lenticular, and are spatially and temporally related to diorite porphyry dykes in the ore district. The deposit is associated with epidote, chlorite, garnet, diopside, K-feldspar, quartz, and carbonate wall-rock alteration. On the basis of field evidence and petrographic analysis, three stages of mineralization can be distinguished: (1) a prograde skarn stage; (2) a retrograde stage associated with the development of Fe mineralization; and (3) a quartz–sulfide–carbonate stage associated with Cu–Au mineralization. H2O–NaCl and H2O–CO2–(± CH4/N2)–NaCl fluids are present in fluid inclusions in quartz and calcite. These fluids show peak Thof 200–320 °C and salinities of 1.23–13.72 wt.% NaCl equiv. Stable isotope analysis of quartz and calcite yielded values of − 141‰ to − 93‰ δD, 8.1‰ to 15.8‰ δ18OSMOW, − 0.7‰ to 9.6‰ δ18Ofluid, and − 3.9‰ to − 2.7‰ δ13CPDB, indicating that the ore-forming fluids were mainly magmatic fluids, with some contributions from meteoric water. The δ34S values of pyrite and chalcopyrite range from − 4.3‰ to 2.9‰, indicating that the sulfur in the deposit was probably derived from deep-seated magmas. Zircon U–Pb dating (206Pb/238U) of the diorite porphyry yielded a weighted mean age of 377.6 ± 1.4 Ma (MSWD = 0.20), whereas the molybdenite yielded a Re–Os isochron age of 375.2 ± 2.6 Ma (MSWD = 1.4). These geochronological data suggest that the mineralization-related diorite porphyry was emplaced during the Late Devonian, coincident with the timing of mineralization within the Qiaoxiahala Fe–Cu–Au deposit. The geological and geochemical evidence presented here suggests that the Qiaoxiahala Fe–Cu–Au deposit is related to late-stage magmatic–hydrothermal activity of the diorite porphyry, and shares a number of similarities with the IOCG deposits.