Mineralization events in the Xiaokele porphyry Cu (–Mo) deposit, NE China: Evidence from zircon U–Pb and K‐feldspar Ar–Ar geochronology and petrochemistry

Abstract

The Great Xing'an Range (GXR), Northeast (NE) China, is a major polymetallic metallogenic belt in the eastern segment of the Central Asian Orogenic Belt. The newly discovered Xiaokele porphyry Cu (–Mo) deposit lies in the northern GXR. Field geological and geochronological studies have revealed two mineralization events in this deposit: early porphyry‐type Cu (–Mo) mineralization, and later vein‐type Cu mineralization. Previous geochronological studies yielded an age of ca. 147 Ma for the early Cu (–Mo) mineralization. Our 40Ar/39Ar dating yielded 40Ar/39Ar plateau ages of 124.8 ± 0.4 to 124.3 ± 0.4 Ma on K‐feldspar in altered Cu‐mineralized diorite porphyrite dikes that represent the overprinting vein‐type Cu mineralization, consistent with zircon U–Pb ages of the diorite porphyrite (126.4 ± 0.5 to 125.0 ± 0.5 Ma). The Cr and Ni contents and Mg# of the Xiaokele diorite porphyrites are high. The diorite porphyrites at Xiaokele are enriched in light rare‐earth elements (REEs), and large‐ion lithophile elements (e.g., Rb, Ba, and K), are depleted in heavy REEs and high‐field‐strength elements (e.g., Nb, Ta, and Ti), and have weak negative εHf(t) values (+0.29 to +5.27) with two‐stage model ages (TDM2) of 1,164–845 Ma. Given the regional tectonic setting in Early Cretaceous, the ore‐bearing diorite porphyrites were likely formed in an extensional environment related to lithospheric delamination and asthenospheric upwelling induced by subduction of the Paleo‐Pacific Plate. These tectonic events caused large‐scale magmatic activity, ore mineralization, and lithospheric thinning in NE China.

Petrogenesis, W metallogenic and tectonic implications of granitic intrusions in the southern Great Xing’an Range W belt, NE China: insights from the Narenwula Complex

“…However, this model was later abandoned because late Mesozoic magmatism in the Great Xing'an Range (GXR) lasted for a relatively long period of time (40 Ma), distinguishing it from the short-lived intense period of magmatic eruption expected to result from a mantle plume (Wu et al 2011). More recent studies have suggested a genetic relationship between the late Mesozoic magmatism in NE China and the subduction of the PPO (Ji et al 2019;Li, S. Z. et al 2019;Suo et al 2019;He et al 2020;Sun et al 2020;Wei et al 2020;Jing et al 2021). However, this scenario can be precluded because (1) late Mesozoic SGB magmatism likely occurred far from (> 2000 km) the PPO subduction front, whereas the maximum extent of the PPO plate subduction is evaluated as 1300 km (Wan et al 2019); (2) seismological studies suggest that back-arc extension led by the PPO subduction did not reach the late Mesozoic SGB ; and (3) during Late Jurassic time, igneous rocks were mainly distributed in the GXR and absent in other regions of NE China, indicating that the PPO plate was rotating and undergoing oblique subduction beneath the Eurasian continent during this time (Maruyama et al 1997;Xu, W. L. et al 2013).…”

“…However, the overprinting of the Palaeo-Asian Ocean (PAO), Mongol-Okhotsk Ocean (MOO) and Palaeo-Pacific Ocean (PPO) tectonic regimes had significant influence on the SGB during late Mesozoic time, which has led to disagreements on the interpretation of the deep geodynamic processes and limited our understanding of regional W-related granitic magmatism and W mineralization. Several models have been proposed for the SGB tectonic setting during late Mesozoic time, including (a) upwelling of a mantle plume (Wang, T. et al 2015), (b) post-orogenic gravitational collapse and/or subductioninduced back-arc extension related to the closure of the MOO (Wang, Z. H. et al 2015;Fritzell et al 2016;Guan et al 2018;Ji et al 2018Ji et al , 2020Han et al 2021;Shi et al 2020;Wei et al 2021), (c) arc/back-arc extension and asthenosphere upwelling induced by subduction of the PPO (Ji et al 2019;Li, S. Z. et al 2019;Suo et al 2019;He et al 2020;Sun et al 2020;Wei et al 2020;Jing et al 2021), and (d) compositional effects resulting from the closure of the MOO and subduction of the PPO (Ouyang et al 2015;Liu, C. F. et al 2017;Liu et al 2020;Pang et al 2020;Zhang, C. et al 2020;Mi et al 2021). Additionally, although researchers generally agree that the disappearance of the PAO occurred along the Solonker-Xar Moron-Changchun Fault (SXCF), the closure time of the PAO remains ambiguous (Liu, Y. J. et al 2017).…”

Fluid Inclusions and C–H–O–S–Pb Isotopes of the Huoluotai Porphyry Cu (Mo) Deposit in the Northern Great Xing’an Range, NE China: Implications for Ore Genesis

“…The exposed strata in the Erguna Block mainly consist of Paleozoic marine sediments [20], widely distributed Mesozoic terrigenous clastic rocks, and volcanic rocks [21]. Magmatism in the NGXR can be divided into Paleozoic, Early-Middle Triassic, Late Triassic-Early Jurassic, Middle-Late Jurassic, and Cretaceous (Figure 1C; [12,[22][23][24]).…”

Mineralization Age and Hydrothermal Evolution of the Fukeshan Cu (Mo) Deposit in the Northern Great Xing’an Range, Northeast China: Evidence from Fluid Inclusions, H–O–S–Pb Isotopes, and Re–Os Geochronology

“…The intrusive rocks in the region are mainly Paleozoic and Mesozoic granites [24,31]. According to recent geochronological data, they can be divided into four stages: Early Paleozoic, Late Paleozoic, Late Triassic-Early Jurassic, and Late Jurassic-Early Cretaceous [24,26,32]. In addition, previous studies on Early Paleozoic post-orogenic granites in the Tahe-Mohe area and blueschist facies metamorphic rocks in Toudaoqiao have shown that the amalgamation of the Erguna and Xing'an blocks occurred at ca.…”