1. A newly identified Permian distal skarn deposit in the Western Tianshan, China: New evidence from geology, garnet U[sbnd]Pb geochronology and S[sbnd]Pb[sbnd]C[sbnd]H[sbnd]O isotopes of the Arqiale Pb[sbnd]Zn[sbnd]Cu deposit.
- Author
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Peng, Yi-Wei, Zou, Hao, Bagas, Leon, Shen, Yu-Fan, Shu, Zhi-Ping, Su, Jing, Liang, Qing-Dong, Wang, Chun-Shan, Hu, Yao-Hua, and Zhang, Heng
- Subjects
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GEOLOGY , *SKARN , *GARNET , *HYDROTHERMAL deposits , *ISOTOPES , *GEOLOGICAL time scales , *SPHALERITE - Abstract
[Display omitted] • Garnet LA-ICP-MS U Pb dating yielded a lower-intersect age of 268.6 ± 5.9 Ma. • The initial hydrothermal fluids are magmatic water, mixing with meteoric water. • Arqiale is classified as a distal skarn Pb Zn Cu deposit. • Arqiale underwent two stage exhumation events in the Mesozoic and Cenozoic. • The causative intrusions and Cu mineralization may occur at depth in the north. The Arqiale Pb Zn Cu deposit is located in the Wusun Range, Western Tianshan, China. Prograde and retrograde skarn minerals are abundant and associated with the Pb Zn Cu mineralization. Given that the orebodies are stratabound and hosted in limestone and causative intrusions were not identified, the genetic relationship between mineralization and magmatic hydrothermal activity remains controversial. Geology, in-situ garnet LA-ICP-MS U Pb dating and S Pb C H O isotopes were carried out in this study, aiming to constrain the mineralization age, source of ore-forming components, and examine the link between mineralization and magmatism. In-situ garnet LA-ICP-MS U Pb dating yielded a well-defined lower-intercept age of 268.6 ± 5.9 Ma, reflecting that the mineralization occurred much younger than that of ore hosting strata and formed in a post-collisional setting. In-situ δ34S values of sulfides (chalcopyrite, sphalerite and pyrite) range from −5.81‰ to −7.57‰ with an average of −6.37‰. The δ34S values of sulfide separates published previously vary from −7.1‰ to 1.3‰ (average −1.5‰). The in-situ 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of galena vary from 18.262 to 18.269, 15.561 to 15.567 and 38.049 to 38.065, respectively. The aforementioned S-Pb isotopic compositions indicate that the metals and sulfur were sourced partially from causative intrusion and partially from hosing sedimentary rocks. The δ13C (-2.6 – −0.9‰), δ18O V-SMOW (3.2 – 7.7‰), δ18O H2O (-5.2 – −0.7‰) and δD H2O (-128.0 – −109.1‰) values of ore-bearing calcite suggest that the ore-forming fluids were initially sourced from magmatic water exsolved from the hidden causative intrusions, with increasing input of meteoric water in later time. These geological, geochemical and isotopic data confirm that Arqiale is a typical distal skarn Pb Zn Cu deposit. Considering the chalcopyrite-garnet-ilvaite contents increasing and Zn/Pb rations decreasing from the shallow part in the south to the deeper part in the north, it is inferred that the hidden causative intrusions and Cu mineralization within contact zone may occur at depth in the northern part of Arqiale. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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