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Rongqing Zhang - One of the best experts on this subject based on the ideXlab platform.
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late cretaceous granitic magmatism and sn mineralization in the giant yinyan porphyry tin deposit south china constraints from zircon and Cassiterite u pb and molybdenite re os geochronology
Mineralium Deposita, 2021Co-Authors: Weiguang Zhu, Rongqing Zhang, Hong Zhong, Xiaoyu Zhao, Wei MaoAbstract:The Yinyan porphyry tin deposit in western Guangdong is spatially associated with quartz porphyry and granite porphyry. LA–ICP–MS zircon U–Pb dating defined an emplacement age of 78.5 ± 0.4 Ma for the quartz porphyry and 79.2 ± 0.9 Ma for the granite porphyry. LA–ICP–MS Cassiterite U–Pb dating yielded Tera–Wasserburg lower intercept ages of 78.5 ± 0.6, 78.6 ± 1.2, and 78.2 ± 0.7 Ma, for Cassiterite from a Cassiterite–sulfide vein, Cassiterite–sulfide ore, and a Cassiterite–topaz–quartz stringer, respectively. Re–Os dating of molybdenite from seven different veins yielded an isochron age of 77.0 ± 0.5 Ma. All these new age data are indistinguishable within analytical uncertainty and, therefore, indicate a genetic relationship between the Sn mineralization and the porphyry magmatism in the Yinyan deposit. The REE tetrad effect and very low Nb/Ta and Zr/Hf ratios indicate that the quartz porphyry and the granite porphyry are highly evolved. The U–Pb dated Cassiterite is enriched in Fe, W, and U and in high field strength elements (HFSEs) such as Zr, Hf, Nb, and Ta. The high Fe, Nb, and Ta contents may be responsible for the dark luminescence of Cassiterite in CL images. The Zr/Hf ratio of Cassiterite may potentially be used to distinguish the mineralization type. Cassiterite from pegmatites has lower Zr/Hf ratios (~ 5–6) in comparison with granite/greisen-related (~ 9–30) Cassiterite. Cassiterite from the early hydrothermal stage typically contains higher amounts of Ti, Nb, Ta, Zr, and Hf than that from the late hydrothermal stage. In combination with published geochronological data of other Sn–W deposits in the western Guangdong Province, two Sn–W metallogenic events at ca. 85 and 77–80 Ma have been identified. These two metallogenic events are part of a larger-scale 75–100 Ma Sn–W mineralization event in South China, which we suggest was probably related to the subduction of the Neo-Tethyan oceanic plate.
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neoproterozoic mineralization in a hydrothermal Cassiterite sulfide deposit at jiumao northern guangxi south china mineral scale constraints on metal origins and ore forming processes
Ore Geology Reviews, 2018Co-Authors: Lu Xiang, Stanislas Sizaret, Rucheng Wang, Wenlan Zhang, Saskia Erdmann, Lei Xie, Xudong Che, Rongqing ZhangAbstract:Abstract Most tin deposits worldwide are inferred to have formed from fluids derived from evolved (granitic) magma systems. Neoproterozoic silicate- and sulfide-stage Sn deposits at Jiumao of South China, in contrast, have been thought to be derived from metasedimentary and mafic-ultramafic host rocks. The Sn deposit may thus have formed by components and processes distinct from those that commonly contribute to Sn deposits, although spatially associated greisen-hosted Sn deposits also occur. To characterize in detail the formation of the Jiumao ore deposits, which contain ∼28,000 t of Sn, we present new field and petrographic observations, major- and trace-element compositions for silicate and ore minerals, and U-Pb age data of Cassiterites and zircons for the deposits and granites. Our research shows that (1) the granite-greisen system formed at ∼830 Ma, which is the earliest Sn mineralization event in South China; (2) the silicate- and sulfide-stage ores in the country rocks formed at an fO2 of ∼NNO with temperatures of 350 °C and 170 °C, respectively; (3) all vein-type Sn ores at Jiumao were formed by Sn-F-B-rich fluids that were derived from the Yuanbaoshan granite magma system rather than ultramafic rocks; (4) the Fe-rich character of the ores hosted by the metasedimentary rocks and the Mg-rich character of the ores hosted by the ultramafic rocks largely controlled the reactions and efficacy of Cassiterite precipitation and thus ore grade. We highlight that differences in mineral assemblages largely relate to differences of the protolith compositions and fluid-rock reactions (e.g., B- and tourmaline deposition in the ores hosted by the metasedimentary rocks, but not in the ores hosted by the ultramafic rocks). Cassiterite and titanite trace-element compositions reflect fluid composition, protolith composition, and intensive parameters of crystallization.
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age of the dahongliutan rare metal pegmatite deposit west kunlun xinjiang nw china constraints from la icp ms u pb dating of columbite fe and Cassiterite
Ore Geology Reviews, 2016Co-Authors: Qinghe Yan, Zengwang Qiu, He Wang, Min Wang, Xiaopeng Wei, Rongqing Zhang, Jianping LiuAbstract:Abstract Dahongliutan is a medium-size Li–Be–Ta–Nb rare metal pegmatite deposit in the Tianshuihai terrane, West Kunlun orogenic belt (NW China). In this paper, LA–ICP–MS U–Pb ages of columbite-(Fe) and Cassiterite are reported to constrain the metallogenic age. Columbite-(Fe) (with high U and low Th) yielded a Late Triassic weighted mean 206 Pb/ 238 U age of 211.9 ± 2.4 Ma, whilst Cassiterite yielded a 206 Pb/ 238 U– 207 Pb/ 235 U concordia lower intercept age of 218 ± 12 Ma and a Tera-Wasserburg lower intercept age of 218 ± 12 Ma, which is identical to the columbite-(Fe) U-Pb age and thus represents the emplacement age of the pegmatite dikes. The ore-hosting pegmatite dikes are intimately time-space related to the Dahongliutan S-type granite (ca. 220–217 Ma), indicating that they may have been cogenetic. Integrating new and published geological data, we suggest that the Dahongliutan pegmatites may have evolved from the granitic magma represented by the Dahongliutan S-type pluton in a post-collisional tectonic setting. Regionally, the Tianshuihai terrane is the western extension of the Songpan-Ganzi block, and thus the Kunlun Li-mineralization belt may have been connected to the Songpan-Ganzi Li-mineralization belt which contains eleven lithium deposits with about 9.8% of Li 2 O reserves in China, implying that the Dahongliutan pegmatite deposit may also have favorable ore-forming conditions. The similar columbite-(Fe) and Cassiterite ages demonstrate that these minerals can be precisely dated and could provide useful alternatives to accurately constrain the timing and evolution of rare metal mineralization.
Matthieu Harlaux - One of the best experts on this subject based on the ideXlab platform.
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fluid mixing as primary trigger for Cassiterite deposition evidence from in situ δ18o δ11b analysis of tourmaline from the world class san rafael tin copper deposit peru
Earth and Planetary Science Letters, 2021Co-Authors: Andrea Dini, Matthieu Harlaux, Kalin Kouzmanov, Stefano Gialli, Katharina Marger, Annesophie Bouvier, Lukas P Baumgartner, Andrea Rielli, Alain ChauvetAbstract:Abstract We present a high-resolution in situ study of oxygen and boron isotopes measured in tourmaline from the world-class San Rafael Sn (–Cu) deposit (Central Andean tin belt, Peru) aiming to trace major fluid processes at the magmatic-hydrothermal transition leading to the precipitation of Cassiterite. Our results show that late-magmatic and pre-ore hydrothermal tourmaline has similar values of δ 18 O (from 10.6‰ to 14.1‰) and δ 11 B (from −11.5‰ to −6.9‰). The observed δ 18 O and δ 11 B variations are dominantly driven by Rayleigh fractionation, reflecting tourmaline crystallization in a continuously evolving magmatic-hydrothermal system. In contrast, syn-ore hydrothermal tourmaline intergrown with Cassiterite has lower δ 18 O values (from 4.9‰ to 10.2‰) and in part higher δ 11 B values (from −9.9‰ to −5.4‰) than late-magmatic and pre-ore hydrothermal tourmaline, indicating important contribution of meteoric groundwater to the hydrothermal system during ore deposition. Quantitative geochemical modeling demonstrates that the δ 18 O- δ 11 B composition of syn-ore tourmaline records variable degrees of mixing of a hot Sn-rich magmatic brine with meteoric waters that partially exchanged with the host rocks. These results provide thus direct in situ isotopic evidence of fluid mixing as a major mechanism triggering Cassiterite deposition. Further, this work shows that combined in situ δ 18 O and δ 11 B analyses of tourmaline is a powerful approach for understanding fluid processes in dynamic magmatic-hydrothermal environments.
Alain Chauvet - One of the best experts on this subject based on the ideXlab platform.
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fluid mixing as primary trigger for Cassiterite deposition evidence from in situ δ18o δ11b analysis of tourmaline from the world class san rafael tin copper deposit peru
Earth and Planetary Science Letters, 2021Co-Authors: Andrea Dini, Matthieu Harlaux, Kalin Kouzmanov, Stefano Gialli, Katharina Marger, Annesophie Bouvier, Lukas P Baumgartner, Andrea Rielli, Alain ChauvetAbstract:Abstract We present a high-resolution in situ study of oxygen and boron isotopes measured in tourmaline from the world-class San Rafael Sn (–Cu) deposit (Central Andean tin belt, Peru) aiming to trace major fluid processes at the magmatic-hydrothermal transition leading to the precipitation of Cassiterite. Our results show that late-magmatic and pre-ore hydrothermal tourmaline has similar values of δ 18 O (from 10.6‰ to 14.1‰) and δ 11 B (from −11.5‰ to −6.9‰). The observed δ 18 O and δ 11 B variations are dominantly driven by Rayleigh fractionation, reflecting tourmaline crystallization in a continuously evolving magmatic-hydrothermal system. In contrast, syn-ore hydrothermal tourmaline intergrown with Cassiterite has lower δ 18 O values (from 4.9‰ to 10.2‰) and in part higher δ 11 B values (from −9.9‰ to −5.4‰) than late-magmatic and pre-ore hydrothermal tourmaline, indicating important contribution of meteoric groundwater to the hydrothermal system during ore deposition. Quantitative geochemical modeling demonstrates that the δ 18 O- δ 11 B composition of syn-ore tourmaline records variable degrees of mixing of a hot Sn-rich magmatic brine with meteoric waters that partially exchanged with the host rocks. These results provide thus direct in situ isotopic evidence of fluid mixing as a major mechanism triggering Cassiterite deposition. Further, this work shows that combined in situ δ 18 O and δ 11 B analyses of tourmaline is a powerful approach for understanding fluid processes in dynamic magmatic-hydrothermal environments.
A J Boyce - One of the best experts on this subject based on the ideXlab platform.
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stable isotope constraints on ore formation at the san rafael tin copper deposit southeast peru
Economic Geology, 2009Co-Authors: Thomas Wagner, Anthony E Williamsjones, Michael S J Mlynarczyk, A J BoyceAbstract:The San Rafael tin-copper deposit in the Eastern Cordillera of the Peruvian Central Andes is the world’s largest hydrothermal tin lode, with a total resource of about 1 million metric tons metal, at an average grade of 4.7 wt percent Sn. The mineralization is of the Cassiterite-sulfide type and occurs in a vertically extensive veinbreccia system centered on a shallow-level, late Oligocene granitoid stock. The tin ores form Cassiterite-quartzchlorite‐bearing veins and breccias hosted by several large fault-jogs at depth in the lode. By contrast, the copper ores, which contain disseminated acicular Cassiterite, are localized in the upper part of the system. Both ore types are associated with a very distinctive, strong chloritic alteration, which was preceded by intense sericitization, tourmalinization, and tourmaline veining. The δ34S values of the sulfides range between 2 and 6 per mil, and vary very little with location in the deposit. This indicates that the hydrothermal system was large, with a relatively homogeneous source of sulfur, likely of magmatic origin. This is confirmed by stability relationships of ore minerals, which indicate that the ore fluids were initially reducing. Microthermometric studies of fluid inclusions in Cassiterite, quartz, tourmaline, and fluorite show that the fluids responsible for the early, barren stage were hot, hypersaline brines (380°‐540°C, 34‐62% NaCl equiv), whereas the ore-stage fluids had moderate to low salinity (0‐21 wt % NaCl equiv), and were of moderate temperature (290°‐380°C). In addition to the marked dilution of the ore fluids with evolution of the hydrothermal system, they became progressively more oxidizing, as inferred by the local association of minor hematite with Cassiterite and the ubiquitous replacement of pyrrhotite by pyrite and marcasite. The δ18O values of the fluid decreased systematically with time, as indicated by the δ18O values of different generations of tourmaline, Cassiterite, and quartz. This evolution was paralleled by an increase in the δD values of the fluid, inferred from the δD values of tourmaline and chlorite. This trend is consistent with mixing of the ore fluids with a cooler fluid that had substantially lower δ18O, and cannot be explained by fluid boiling. Based on structural evidence for an opening of the vein system and a transition from lithostatic to hydrostatic conditions at the onset of mineralization, we infer that ore deposition was caused by an influx of hot groundwater of meteoric origin which mixed repeatedly with tin-bearing magmatic brines. The oxidation, dilution, cooling, and acid neutralization of the ore fluids destabilized chloride complexes of tin and triggered the large-scale precipitation of Cassiterite.
Jianping Liu - One of the best experts on this subject based on the ideXlab platform.
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age of the dahongliutan rare metal pegmatite deposit west kunlun xinjiang nw china constraints from la icp ms u pb dating of columbite fe and Cassiterite
Ore Geology Reviews, 2016Co-Authors: Qinghe Yan, Zengwang Qiu, He Wang, Min Wang, Xiaopeng Wei, Rongqing Zhang, Jianping LiuAbstract:Abstract Dahongliutan is a medium-size Li–Be–Ta–Nb rare metal pegmatite deposit in the Tianshuihai terrane, West Kunlun orogenic belt (NW China). In this paper, LA–ICP–MS U–Pb ages of columbite-(Fe) and Cassiterite are reported to constrain the metallogenic age. Columbite-(Fe) (with high U and low Th) yielded a Late Triassic weighted mean 206 Pb/ 238 U age of 211.9 ± 2.4 Ma, whilst Cassiterite yielded a 206 Pb/ 238 U– 207 Pb/ 235 U concordia lower intercept age of 218 ± 12 Ma and a Tera-Wasserburg lower intercept age of 218 ± 12 Ma, which is identical to the columbite-(Fe) U-Pb age and thus represents the emplacement age of the pegmatite dikes. The ore-hosting pegmatite dikes are intimately time-space related to the Dahongliutan S-type granite (ca. 220–217 Ma), indicating that they may have been cogenetic. Integrating new and published geological data, we suggest that the Dahongliutan pegmatites may have evolved from the granitic magma represented by the Dahongliutan S-type pluton in a post-collisional tectonic setting. Regionally, the Tianshuihai terrane is the western extension of the Songpan-Ganzi block, and thus the Kunlun Li-mineralization belt may have been connected to the Songpan-Ganzi Li-mineralization belt which contains eleven lithium deposits with about 9.8% of Li 2 O reserves in China, implying that the Dahongliutan pegmatite deposit may also have favorable ore-forming conditions. The similar columbite-(Fe) and Cassiterite ages demonstrate that these minerals can be precisely dated and could provide useful alternatives to accurately constrain the timing and evolution of rare metal mineralization.