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Wu C.,CAS Guangzhou Institute of Geochemistry | Wu C.,University of Chinese Academy of Sciences | Chen H.,CAS Guangzhou Institute of Geochemistry | Hollings P.,Lakehead University | And 9 more authors.
Ore Geology Reviews | Year: 2015

The Halasu porphyry copper belt situated in the East Junggar is one of the major porphyry copper belts in Xinjiang Uygur Autonomous Region, northwest China. Copper and molybdenum mineralization occurs as disseminated sulfides or veinlets mainly in granodiorite porphyry and diorite porphyry, with the intense development of zoned alteration from potassic, through sericitic to an outer zone of propylitic alteration.New LA-ICP-MS zircon U-Pb dating reveals that magmatism in the belt can be divided into three periods during the Middle Devonian and Early Carboniferous, namely the pre-mineralization stage of 390. Ma, syn-mineralization stage of 382-372. Ma, and post-mineralization stage of 350-320. Ma. The syn-mineralization intrusions are calc-alkaline, whereas pre- and post-mineralization intrusions are shoshonitic and high-K calc-alkaline. The syn-mineralization intrusions are enriched in highly incompatible trace elements but depleted in Nb, Ta, Hf and Ti relative to the pre- and post-mineralization intrusions.Zircon trace elements analyses demonstrate a negative correlation between Ti-in-zircon temperatures and oxygen fugacity. Ore-bearing syn-mineralization granitoids are characterized by higher water content, oxygen fugacity and low temperatures with higher mineralization potential than pre- and post-mineralization ones. These characteristics, together with the geochemical signature of the intrusions, suggest that the ore-bearing porphyries are derived from relative high fH2O magma reservoir. The remarkably homogeneous Hf isotopic compositions (εHf(t)=8 to 13) from syn-mineralization intrusions span over 10m.y., suggesting the existence of a long-lived reservoir beneath Halasu belt during the Middle Devonian. All the intrusions have low initial 87Sr/86Sr values (0.703935 to 0.707172), high εNd(t) values (4.7 to 5.5) and young crustal model ages (650 to 750Ma). Combined with the mantle-derived Pb isotope characteristics, the Sr-Nd-Hf data suggest that the parental magma was probably derived from flat subduction triggered partial melting of juvenile crust generated during subduction-accretionary process with no significant input of old crust, whereas pre-mineralization and post-mineralization intrusions are supposed to emplaced in immature island arc setting and post-orogenic setting, respectively. © 2015.

Yang F.,Chinese Academy of Geological Sciences | Mao J.,Chinese Academy of Geological Sciences | Pirajno F.,Geological Survey of Western Australia | Yan S.,Center Geology and Mineral Exploration Foundation Manage Center | And 6 more authors.
Journal of Asian Earth Sciences | Year: 2012

In this review, we describe the geological characteristics of porphyry copper deposits in Junggar region, Xinjiang, and place these into their metallogenic-tectonic context. These porphyry copper deposits are mainly found in four metallogenic belts: (1) a Late Silurian to Early Devonian Cu-Mo metallogenic belt in the Qiongheba area; (2) the Late Devonian Kalaxiange'er Cu metallogenic belt; (3) the Early Carboniferous Xilekuduke-Suoerkuduke porphyry-skarn Cu-Mo metallogenic belt; and (4) the Late Carboniferous Baogutu porphyry Cu metallogenic belt. The ages of mineralization can be divided into three broad intervals: <427-409. Ma, 378-374. Ma and 327-310. Ma. Homogenization temperatures of fluid inclusions in the porphyry copper deposits range mainly from 300 to 180 °C. Salinity ranges from 0.5 to 21.7. wt.% NaCl equiv and 28.9 to 66.76. wt.% NaCl equiv. Ore-forming fluids in the Baogutu and Yunyingshan deposits in the Baogutu and Qiongheba belts, were mainly derived from magmatic fluids, whereas those in the Halasu, Yulekenhalasu and Xilekuduke deposits in the Kalaxiange'er and Xilekuduke-Suoerkuduke belts were mainly derived from magmatic fluids, with some contributions from meteoric water. Sulfur isotope compositions of some porphyry copper deposits cluster around 0‰, indicating that the sulfur was probably derived from mantle-related magmas. The ore-forming processes in all porphyry copper deposits are closely related to the emplacement of intermediate, intermediate-felsic and felsic porphyry intrusions. Porphyry copper deposits in Junggar region developed in a range of tectonic regimes including continental arc, ocean island arc and post collisional settings. © 2011 Elsevier Ltd.

Yang F.,Chinese Academy of Geological Sciences | Mao J.,Chinese Academy of Geological Sciences | Liu F.,Chinese Academy of Geological Sciences | Chai F.,Xinjiang University | And 4 more authors.
Australian Journal of Earth Sciences | Year: 2010

SHRIMP U-Pb zircon dating of a granite in the Mengku iron district, Altay, Xinjiang, yielded an age of 400 ± 6 Ma (MSDW = 1.3), which is similar to the age (SHRIMP U-Pb zircon age 404 ± 8 Ma) of granite north of orebody No. 1 in the Mengku iron deposit. This indicates that the two plutons are of Early Devonian age. These plutons intruded the Kangbutiebao Formation, thereby constraining the age of the Kangbutiebao Formation to > 404 Ma. The Mengku granite and granite north of the No. 1 orebody are characterised by high silica (SiO2 = 72.29-78.63%), Na enrichment (Na2O = 4.12-7.98%), elevated Th, La, Ce, Nd and LREE, depleted Nb, Ta, P and Ti, as well as moderate negative Eu anomalies (δEu = 0.38-0.65). The granites belong to the low-K (tholeiitic) series with Na2O/K2O = 6.36-196.25 and are metaluminous and slightly peraluminous with alumina oversaturation indices of 0.97-1.09. Sr-Nd isotopic analyses [e{open}Nd(t) = 1.04-2.17] indicate that the sources of the Mengku pluton are predominantly mantle-derived, contaminated with small amounts of crustal components. Chemical, isotopic and structural characteristics indicate that granites in the Mengku district originated in a continental-arc setting associated with plate subduction. © 2010 Geological Society of Australia.

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Loading No. 4 Geological Party of the Xinjiang Bureau of Geology and Mineral Exploration and Development collaborators