Homogeneous Zn isotopic compositions in the Maozu Zn-Pb ore deposit in Yunnan Province, southwestern China

Zhang, Hongjie; Xiao, Chaoyi; Wen, Hao; Zhu, Xiangkun; Ye, Lin; Huang, Zhilong; Zhou, Jia‐Xi; Fan, Haifeng

doi:10.1016/j.oregeorev.2019.04.004

Cited by 26 publications

(17 citation statements)

References 40 publications

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“…The copper enrichment is generally linked to phyllic and chlorite-sericite alterations. Three typical Cu-sulfide-bearing veins are recognized in the main stage, including quartz-chalcopyrite-magnetite ± pyrite, quartz-bornite ± chalcopyrite ± chlorite ± epidote ± pyrite, and quartz-chalcopyrite ± chlorite ± pyrite ± rutile veins [23]. Stage IV is defined by mineral associations of calcite, quartz, chlorite, anhydrite, epidote, and pyrite.…”

Section: Geology Of Tuwu Depositmentioning

confidence: 99%

“…The three recognized mineralized zones are referred to as I, II, and III ore zones (Figure 2a), where the ore zone II accounts for 90% of the total copper reserves. Hydrothermal alteration at Tuwu affecting porphyries, and wall-rocks can be divided into potassic, phyllic, propylitic, and limited argillic alteration zones, which are shown in Figure 2c [23,26].…”

Section: Geology Of Tuwu Depositmentioning

confidence: 99%

“…Copper mineralization, mostly present as chalcopyrite and bornite, is closely related to the potassic and phyllic alteration zones. The mineralization process at Tuwu includes four stages based on mineral assemblages and crosscutting relationships [23,28,30]. Stage I is represented by two types of veins, including quartz-magnetite-biotite and quartzmagnetite ± K-feldspar ± albite ± pyrite veins associated with local potassic and late pervasive chlorite alterations.…”

Section: Geology Of Tuwu Depositmentioning

confidence: 99%

“…The porphyry Cu deposit, as an economically important type of deposit supplies approximately 75 percent of global Cu [21,22]. The Early Carboniferous Tuwu deposit that formed in the Dananhu-Tousuquan Arc setting is one of the largest porphyry Cu deposits in the Eastern Tianshan Orogen, Xinjiang, northwestern China region [23][24][25]. Numerous studies have examined the ore genesis of Tuwu through mineralogy, geochemistry, tectonics, multiple isotopes, and fluid inclusions [23,[26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…The Early Carboniferous Tuwu deposit that formed in the Dananhu-Tousuquan Arc setting is one of the largest porphyry Cu deposits in the Eastern Tianshan Orogen, Xinjiang, northwestern China region [23][24][25]. Numerous studies have examined the ore genesis of Tuwu through mineralogy, geochemistry, tectonics, multiple isotopes, and fluid inclusions [23,[26][27][28]. However, few studies have dealt with rutile minerals that are well developed and related to calc-alkalic porphyry alteration and mineralization in the Tuwu porphyry Cu deposit.…”

Section: Introductionmentioning

confidence: 99%

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Rutile and Chlorite Geochemistry Constraints on the Formation of the Tuwu Porphyry Cu Deposit, Eastern Tianshan and Its Exploration Significance

et al. 2021

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The chemical composition of rutile has been used as an indicator in magmatic and metamorphic-related diagenetic systems, but rarely in porphyry-style ore systems. The Tuwu deposit (557 Mt at 0.58% Cu) is a large porphyry-style Cu mineralization in Eastern Tianshan, Xinjiang, with typical disseminated, stockwork mineralized veins hosted in tonalite and diorite porphyry, and to a lesser extent in volcanic rocks of the Qi’eshan Group. We first present determination of rutile minerals coupled with chlorite identified in mineralized porphyries from Tuwu to reveal their geochemical features, thus providing new insights into the ore-forming processes and metal exploration. Petrographic and BSE observations show that the rutile generally occurs as large crystals (30 to 80 µm), in association with hydrothermal quartz, chlorite, pyrite, and chalcopyrite. The rutile grains display V, Fe, and Sn enrichment and flat LREE-MREE patterns, indicating a hydrothermal origin. Titanium in rutile (TiO2) is suggested to be sourced from the breakdown and re-equilibration of primary magmatic biotite and Ti-magnetite, and substituted by Sn4+, high field strength elements (HFSE; e.g., Zr4+ and Hf4+), and minor Mo4+ under hydrothermal conditions. The extremely low Mo values (average 30 ppm) in rutile may be due to rutile formation postdating that of Mo sulfides (MoS2) formation in hydrothermal fluids. Chlorite analyses imply that the ore-forming fluids of the main stage were weakly oxidized (logfO2 = −28.5 to −22.1) and of intermediate temperatures (308 to 372 °C), consistent with previous fluid inclusion studies. In addition, Zr-in-rutile geothermometer yields overestimated temperatures (>430 °C) as excess Zr is incorporated into rutile, which is likely caused by fast crystal growth or post crystallization modification by F-Cl-bearing fluid. Thus, application of this geothermometer to magmatic-hydrothermal ore systems is questionable. Based on the comparison of rutile characteristics of porphyry Cu with other types of ore deposits and barren rocks, we suggest that porphyry Cu-related rutile typically has larger grain size, is enriched in V (average 3408 ppm, compared to <1500 ppm of barren rocks) and to a lesser extent in W and Sn (average 121 and 196 ppm, respectively), and has elevated Cr + V/Nb + Ta ratios. These distinctive signatures can be used as critical indicators of porphyry-style Cu mineralization and may serve as a valuable tool in mineral exploration.

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Section: Geology Of Tuwu Depositmentioning

confidence: 99%

Section: Geology Of Tuwu Depositmentioning

confidence: 99%