Stratabound skarn Pb-Zn mineralization in the Yunkai Domain (South China): The Fozichong case
Stratabound skarn Pb-Zn mineralization in the Yunkai Domain (South China): The Fozichong case
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云开域（华南）层控矽卡岩铅锌矿化：佛子冲案例
DOI：
10.1016/j.oregeorev.2020.103673
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发表时间：
2020-10
影响因子：
3.3
通讯作者：
Wang Cheng-Ming
中科院分区：
文献类型：
--
作者：
Yu Peng-Peng;Zheng Yi;Huang Xi;Wang Cheng-Ming
佛子冲铅锌矿区位于中国南方秦杭成矿带南段云开域，是一个大型层控矿床。矿体以层状、似层状为主，产于燕山期斑岩侵入的奥陶系、志留系地层中。这些矿床在同生沉积喷流（SEDEX）和后生矽卡岩型之间存在争议。由于矿体的产出伴随着绿色层状岩（GSR），因此GSR成因可能对解决争议起到重要作用。这促使我们进行了一系列的岩石学调查，全岩和矿物化学分析的GSR结合锆石U-Pb年代学的侵入体。详细的岩相学观察表明，与传统的矽卡岩相似，海硅渣岩主要由石榴石、辉石、绿帘石、角闪石和榴辉岩组成。此外，与矿石有关的铅，锌，铜和钡的浓度一致下降，从边缘到核心的一个单独的GSR层，支持热液流体交代的起源，而不是比较均匀的沉积。因此，文献上将佛子冲火山灰岩称为层状矽卡岩。矽卡岩中贫锰富钙的钙铁榴石、透辉石-钙铁榴石和钙质角闪石为岩浆热液成因提供了有力证据。由于矽卡岩不局限于侵入接触带内，因此认为是岩浆热液渗透形成的。区内多期次岩浆侵入，热液来源复杂。研究表明，燕山晚期斑岩（锆石U-Pb年龄为100 Ma左右，包括英安斑岩和花岗斑岩）与佛子冲矽卡岩成矿有成因联系，印支期大冲岩体和燕山早期广平岩体与成矿关系不大。矽卡岩系统的氧化还原状态从氧化（退变质阶段和退变质阶段）到还原（退变质晚期和石英硫化物阶段）的变化，如矽卡岩矿物中Fe 2 +/Fe 3+比值所记录的（即，0.05石榴子石、角闪石和尖晶石分别为0.01-0.23和55.6-178.1）。在氧化还原转变过程中，矿化作用在中等温度（约255至278 °C）下随着碳酸盐的沉淀而发展。综合以上分析，佛子冲是中国南方云开域层控矽卡岩型铅锌成矿系统的代表。
The Fozichong Pb-Zn ore district, located in the Yunkai Domain, southern section of the Qin-Hang Metallogenic Belt (QHMB) in South China, consists of several large-size stratabound ore deposits. The ore bodies are mainly stratiform and stratoid, bounded within the Ordovician and Silurian strata that are intruded by the Yanshanian porphyries. These deposits are debated between syngenetic sedimentary exhalative (SEDEX)- and epigenetic skarn-type. Since the occurrence of ore bodies is accompanied by the green-color stratiform rock (GSR), the GSR origin may play an important role to resolve the controversy. This motivates us to conduct a set of petrographic investigations, whole-rock and mineral chemistry analyses of the GSR coupled with zircon U–Pb geochronology of the intrusions. Detailed petrographic observations reveal that the GSR is mainly composed of a mineral assemblage of garnet, pyroxene, epidote, amphibole and chlorite, in analogy with that of traditional skarns. In addition, the concentrations of ore-related Pb, Zn, Cu and Ba consistently decrease from rim to core of an individual GSR layer, supporting an origin of hydrothermal fluid replacement rather than comparatively homogeneous sedimentation. Therefore, the Fozichong GSR is referred to as the stratiform skarn in literature. The Mn-poor and Ca-rich andradite, diopside-hedenbergite and calcic amphibole in the skarn provide robust evidence for the magmatic hydrothermal origin. The skarn is believed to be formed by the infiltration of magmatic hydrothermal fluids since it is not confined in the intrusion contact zone. Where the hydrothermal fluids derived from is complicated due to the multi-stages magmatic intrusions present in the district. Detailed investigations indicate that the late Yanshanian porphyries (zircon U–Pb dated at ~ 100 Ma, including dacite porphyry and granite porphyry) have a genetic link with the Fozichong skarn mineralization, while the Indosinian Dachong pluton and the early Yanshanian Guangping pluton exhibit insignificant correlation with the mineralization. The redox state of the skarn system changes from oxidation (prograde and retrograde stages) to reduction (late retrograde and quartz-sulfide stages), as recorded by the Fe2+/Fe3+ratios in skarn minerals (i.e., 0.05 for garnet, 0.01–0.23 for amphibole and 55.6–178.1 for chlorite, respectively). During the redox transition, the mineralization has been developed with the precipitation of chlorite at moderate temperatures (~255 to 278 °C). In combined with the above analyses, the Fozichong is representative of a stratabound skarn Pb-Zn mineralization system in the Yunkai Domain, South China.
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影响因子：
5.8
作者：
F. Lieben;R. Moritz;L. Fontboté
通讯作者：
F. Lieben;R. Moritz;L. Fontboté
DOI：
10.1007/978-3-642-41714-6_180591
发表时间：
1970-02
期刊：
--
影响因子：
--
作者：
通讯作者：
--
影响因子：
3.3
作者：
Changming Wang;Jun Deng;E. Carranza;Xiangru Lai
通讯作者：
Changming Wang;Jun Deng;E. Carranza;Xiangru Lai
DOI：
10.1080/00167618308729268
发表时间：
1983-12
期刊：
--
影响因子：
--
作者：
G. Taylor
通讯作者：
G. Taylor
影响因子：
6.1
作者：
Yuejun Wang;W. Fan;Guowei Zhang;Yanhua Zhang
通讯作者：
Yuejun Wang;W. Fan;Guowei Zhang;Yanhua Zhang