Petrogenesis and geodynamic implications of Early Palaeozoic granitic rocks at the Hongshi Cu deposit in East Tianshan Orogenic Belt, NW China: Constraints from zircon U–Pb geochronology, geochemistry, and Sr–Nd–Hf isotopes

Abstract

The Early Palaeozoic granitoid rocks represent a volumetrical component of the eastern part of the Dananhu–Tousuquan island arc belt of the East Tianshan and preserve useful information about the tectonomagmatic history of this region. The Hongshi intrusion primarily consists of granodiorite, which intrudes the Ordovician–Silurian Daliugou Formation in the Kalatag area. Zircon U–Pb dating of magmatic zircons from the granodiorite was formed at 426.6 ± 2.3 Ma, suggesting that the intrusion was emplaced in the Middle Silurian. Geochemically, granodiorite belongs to the metaluminous calc‐alkaline I‐type granitoids associated with a narrow range of SiO2 concentration (63.53–67.71 wt.%), A/CNK values ranging from 1.01 to 1.12. They have high Ba, LREE, and LILE contents and low abundance of HREE and HFSE. These samples displayed MgO contents of 1.38–1.52 wt.%, resulting in low K2O/Na2O ratios of 0.11–0.33 and intermediate Mg# values of 29.03–37.31, with high Sr/Y, La/Yb, and Ba/Th ratios, positive εNd(t) (6.60 to 7.95) and εHf(t) (13.1–16.0), low (87Sr/86Sr)i (0.704113–0.704312), and low Nb/U and Ta/U ratios. These features indicated that the parental magma of the granodiorite was probably derived from a juvenile crust with no significant mantle component involvement. Based on the regional geology and geochemical evidence, the Hongshi granodiorite is considered to have formed in an arc setting, associated with the northward subduction of the young Kangguer Ocean slab beneath the Dananhu island arc.

Fluid evolution and metallogenesis of the Meiling Cu‐polymetallic deposit in the East Tianshan, NW China: Constraints from ore geology, fluid inclusions, stable isotope, and U–Pb geochronology

“…The Kalatag district is located in the central part of the Harlik–Dananhu Arc in the East Tianshan belt (Figure 1b). During the past 20 years, several Cu–Zn deposits have been discovered in this area, including the Huangtupo (containing the Honghai) volcanogenic massive sulphide (VMS) Cu–Zn deposit (Chai et al, 2019; Deng, Mathur, et al, 2019; Deng, Wang, et al, 2019; Mao et al, 2019; Yang, Yang, Santosh, Xu, & Wang, 2018), the Hongshi copper deposit and Meiling polymetallic copper deposit (Cheng et al, 2019; Cheng, Yang, Zhang, Xu, & Li, 2020; Cheng, Yang, Zhang, Xu, & Yang, 2020; Deng et al, 2014), the Hongshan epithermal Cu–Au deposit, the Yudai porphyry Cu deposit and Yueyawan magmatic Cu–Ni deposit (Sun et al, 2018). Subsequently, more attentions have been paid on the recently documented Late Palaeozoic mineralization, which includes the Meiling deposit.…”

Palaeozoic tectonic evolution and magmatism in the Kalatag area, East Tianshan, NW China: Evidence from the geochronology and geochemistry of intrusive rocks

“…The zircon U–Pb ages of the quartz diorite from the southern part of the Kalatag pluton are 419.6–432.7 Ma, as determined in this study. Combined with previous chronological studies, the magma emplacement time of the Kalatag pluton is limited to 420–449 Ma (Cheng, Yang, Zhang, Xu, & Yang, 2020; Du et al, 2018; Xu et al, 2020; Zheng et al, 2018). In this study, the zircon U–Pb ages of the quartz diorite porphyry in the Yudai ore district are 436 and 439 Ma.…”

“…The ore deposits can also provide some information regarding the tectonic evolution of a particular domain. Many studies have discussed the tectonic environment of the magma in the Kalatag area (Du et al, 2017;Mao et al, 2018;Sun et al, 2018;Sun, Wang, Lü, et al, 2019a;Zheng et al, 2018;Chen et al, 2020;Cheng, Yang, Zhang, Xu, & Yang, 2020). The Early Palaeozoic magma intrusion activities and deposits in the Kalatag area F I G U R E 1 (a) Sketch map showing the location of Northern Xinjiang (modified after Sengör, Natalin, & Burtman, 1993;Xiao, Zhang, Qin, Sun, & Li, 2004).…”

Accretionary tectonics, deep structures and metallogeny of southern Altaids

“…In the research conducted by Cheng, Yang, Zhang, Xu and Yang (, this issue), zircon U–Pb geochronology, geochemistry, and Sr–Nd–Hf isotopes of the Early Palaeozoic granitic rocks at the Hongshi Cu deposit of the Dananhu–Tousuquan island arc belt of the East Tianshan imply that the Hongshi granodiorite (426.6 ± 2.3 Ma) was probably derived from a juvenile crust in an arc setting, associated with the northward subduction of the young Kangguer Ocean slab beneath the Dananhu island arc.…”