Geology and C-O-S-Pb isotopes of the Fangyangshan Cu-Pb-Zn deposit in the Baoshan block (SW China): Implications for metal source and ore genesis
Geology and C-O-S-Pb isotopes of the Fangyangshan Cu-Pb-Zn deposit in the Baoshan block (SW China): Implications for metal source and ore genesis
复制标题
保山地块方阳山铜铅锌矿床地质和 C-O-S-Pb 同位素：对金属来源和成矿的启示
DOI：
10.1016/j.oregeorev.2021.103992
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发表时间：
2021-05
影响因子：
3.3
通讯作者：
Wei Liu
中科院分区：
文献类型：
--
作者：
Rong Xu;Wei Chen;Mingguo Deng;Wenchang Li;Fuchuan Chen;Chunkit Lai;Zhen Jia;Wei Liu
方阳山铅锌矿床是在保山地块(中国西南)发现的第一个富铜铅锌矿床，宝山地块是东南亚大陆斯布玛苏地体的北部延续。层控脉状/透镜体矿体赋存于上寒武统沙河场组碳酸盐岩和钙质板岩中。根据矿物共生关系和横切矿脉关系，将方阳山划分为三个主要成矿阶段：成矿前(I)、成矿后(II-1~II-3)和成矿后(III)。金属矿物主要包括黄铁矿、黄铜矿、闪锌矿和方铅矿，非金属矿物主要包括石英和碳酸盐(方解石和白云石)。碳酸盐岩δ13CV-PDB和δ18OV-SMOW值分别为早期(II-1：−3.67-−3.57‰，8.18-8.92‰)、中期(II-2：−5.88-−5.26‰，8.18-10.79‰)、晚期(II-3：−2.79-−2.37‰，9.97-11.42‰)、成矿后(−3.75‰，12.79‰)。这些碳-氧同位素数据表明，早期成矿流体主要来自岩浆来源，流体通过围岩碳酸盐溶解作用增加了沉积输入。I期至II期硫化物具有持续较高的δ34S值(8.24-14.91‰，Avg.11.51‰)，位于岩浆成因和蒸发岩成因的δ34S矿田之间，与宝山地块中一些典型的与岩浆有关的夕卡岩矿床(如芦子园、金昌河、荷桃坪和黑牛洼)相似。这表明防阳山矿石硫可能是岩浆-热液流体与当地碳酸盐-蒸发岩序列中的海水硫酸盐(如石膏)通过热化学硫酸盐还原(TSR)形成的。方阳山硫化物的206Pb/204Pb(18.2984-19.0819)、207Pb/204Pb(15.7731-15.8107)和208Pb/204Pb(38.6550-39.3092)比值与宝山地块和中缅边境附近的许多与岩浆有关的铅锌矿床具有明显的线性正相关和地壳上的亲和力。这也意味着区域铅锌矿建造中的铅(可能还有其他矿石金属)来自深部岩浆流体和上大陆地壳的共同混合来源。结合区域构造成矿背景，我们认为方阳山铜铅锌矿化很可能与邻近的鹿子园远端矽卡岩型巨型矿床共享单一的岩浆热液系统。这些矿床与其他地方的高温碳酸盐置换矿床(CRD)有许多相似之处。
The Fangyangshan deposit is the first Cu-rich Pb-Zn deposit discovered in the Baoshan block (SW China), the northern continuation of the Sibumasu terrane in mainland SE Asia. The stratabound veined/lensoidal orebodies are hosted in the carbonates and calcareous slates of the Upper Cambrian Shahechang Formation. Based on mineral paragenesis and crosscutting vein relationships, three main mineralization stages (pre-ore (I),syn-ore (II-1 to II-3), and post-ore (III)) were identified at Fangyangshan. Metallic minerals include mainly pyrite, chalcopyrite, sphalerite, and galena, whilst non-metallic minerals include mainly quartz and carbonates (calcite and dolomite). The carbonate δ13CV-PDBand δ18OV-SMOWvalues vary from the earlysyn-ore (II-1: −3.67 to −3.57‰, 8.18–8.92‰), middlesyn-ore (II-2: −5.88 to −5.26‰, 8.18–10.79‰), latesyn-ore (II-3: −2.79 to −2.37‰, 9.97–11.42‰), to post-ore (−3.75‰, 12.79‰) stage. These C-O isotope data suggest that the early ore-forming fluids were predominantly derived from a magmatic source, and the fluids have increasing sedimentary input via wallrock carbonate dissolution. The stages I to II sulfides have consistently high δ34S values (8.24–14.91‰, avg. 11.51‰), which lie between the magmatic- and evaporite-derived δ34S fields, resembling some typical magmatic-related skarn deposits (e.g., Luziyuan, Jinchanghe, Hetaoping and Heiniuwa) in the Baoshan block. This indicates that the Fangyangshan ore sulfur may have been derived from mixture of magmatic-hydrothermal fluids and seawater sulfates (e.g., gypsum) from the local carbonate-evaporite sequences via thermochemical sulfate reduction (TSR). The Fangyangshan sulfides show a clearly linear positive correlation and an upper crustal affinity for their206Pb/204Pb (18.2984–19.0819),207Pb/204Pb (15.7731–15.8107), and208Pb/204Pb (38.6550–39.3092) ratios, which is again similar to many magmatic-related Pb-Zn deposits within the Baoshan block and near the Sino-Burmese border. This also implies a common mixed source of deeper magmatic fluid and upper continental crust for the lead (and also probably other ore metals) in the regional Pb-Zn ore formation. Considering the regional tectono-metallogenic setting, we propose that the Fangyangshan Cu-Pb-Zn mineralization most probably shared a single magmatic-hydrothermal system with the nearby giant Luziyuan distal skarn deposit. These deposits have many similarities with the high-temperature carbonate replacement deposits (CRDs) elsewhere.
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影响因子：
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作者：
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通讯作者：
K. Kelley;D. Leach;C. Johnson;J. L. Clark;M. Fayek;J. Slack;V. Anderson;R. Ayuso;W. Ridley
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影响因子：
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作者：
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影响因子：
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作者：
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作者：
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通讯作者：
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影响因子：
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