Petrogenesis of granitoids in the Wulan area: Magmatic activity and tectonic evolution in the North Qaidam, NW China

Fluid Inclusion and H–O–S–Pb Isotope Geochemistry of the Yuka Orogenic Gold Deposit, Northern Qaidam, China

“…Major lithostratigraphic units of the NQOB consist of the Paleoproterozoic Dakendaban Group, Early Paleozoic arc-related volcanic and sedimentary rocks of Tanjianshan Group and Devonian molasse, and Early Paleozoic granitic rocks [37][38][39][40][41][42][43][44][45]. Previous studies have interpreted geochronological and geochemical studies of HP/UHP metamorphic rocks (eclogite and gneiss) from NQOB as reflecting the evolution of a continental orogen from early seafloor subduction (>440 Ma) to continental subduction and collision (440-420 Ma), to the exhumation of the subducted slab (420-390 Ma), and to the final orogen collapse (390-360 Ma) [32,36,39,40,[46][47][48][49][50][51][52]. Moreover, Wu et al [53] have summarized data for NQOB granitoids; the following five periods of granitic magmatism occurred between the Ordovician and Alty n Tag h Fau lt S a i s h i t e n g s h a n -X i t i e s h a n f a u lt O u lo n g b u lu k e -M a o n iu s h a n fa u lt Zo ng wu lon gs ha n fau lt (b)…”

Geochronology, petrogenesis, and tectonic significance of the granites in the Chaqiabeishan area of the Quanji Massif, northwestern China

“…The North Qaidam tectonic Belt (NQTB), which is a tectonic terrane located between the Qaidam Block to the south and the Qilian Block to the north, consists of three tectonic units: The Quanji Massif (QM) in the north, the Tanjianshan volcanic zone (TVZ) in the middle, and the North Qaidam high‐pressure to ultrahigh‐pressure (HP‐UHP) metamorphic belt (NQ‐HP‐UHP) in the south (Figure 1a; Q. Y. Wang, Dong, Pan, Liao, & Guo, 2018). The southern two units (the TVZ and NQ‐HP‐UHP), that is, the Northern Qaidam (NQD), are collectively referred to as the Early Palaeozoic northern subduction‐collision complex (Gong, He, Wang, Chen, & Kusky, 2019; Q. Y. Wang et al, 2018; L. Wang, Johnston, & Chen, 2019; C. L. Wu et al, 2019), which is tectonically related to the Early Palaeozoic South Qilian Ocean, which was a significant branch of the Proto‐Tethys Ocean (Q. Y. Wang et al, 2018; C. L. Wu et al, 2008, 2019). During the Early Palaeozoic, the QM was located within the South Qilian Ocean and was geographically closer to the Qilian Block than to the Qaidam Block.…”

“…The QM and the Qaidam Block were finally amalgamated during subduction‐collision with the TVZ (Q. Y. Wang et al, 2018). Along the Zongwulong tectonic Belt, which borders the QM and the Qilian Block, the Zongwulong Ocean, which was once a small branch of the Palaeo‐Tethys Ocean, is believed to have developed during the Middle Carboniferous to Early Permian in response to continental rifting of the northern margin of the QM (Guo et al, 2009; Peng, Zhang, Sun, Xing, & Yu, 2018; C. L. Wu et al, 2019). Following this rifting, the Zongwulong oceanic plate was subducted obliquely southward under the QM from the Late Permian to Middle Triassic (Guo et al, 2009; Peng et al, 2018; Peng, Ma, Liu, Sun, & Shao, 2016; C. L. Wu et al, 2019).…”

“…Understanding the petrogenesis of the granitoids in the QM is crucial to understanding the tectonic evolution of the South Qilian Ocean, and even of the Zongwulong Ocean. The few granitoids in the QM have provided only minor evidence of the subduction‐collision process related to the South Qilian Ocean (Song, Niu, Zhang, & Zhang, 2019; Q. Y. Wang et al, 2018; C. L. Wu et al, 2019). For example, the continuing northward subduction of the lower plate between 500 and 440 Ma gave rise to further island‐arc magmatism in the QM, which was a continental arc (Q. Y. Wang et al, 2018).…”

“…The South Qilian Ocean was most likely completely closed by ~440 Ma, which is indicated by the Tuanyu Mountain granite (Q. Y. Wang et al, 2018; Wu et al, 2008). In terms of the tectonic evolution of the Zongwulong Ocean, several I‐type granitoids with ages of 240–254 Ma in the Tianjun and Wulan areas within the eastern segment of the QM contain evidence that the Zongwulong oceanic plate had subducted obliquely southward under the QM by the Late Permian to Middle Triassic (Guo et al, 2009; Peng et al, 2016, 2018; C. L. Wu et al, 2019). Concurrently, the Palaeo‐Tethys oceanic plate was subducted northward, forming numerous granitic intrusions with ages of 240–254 Ma in the Eastern Kunlun area (Ding, Jiang, & Sun, 2014; Ding, Liu, & Yan, 2015; Xiong, Ma, Zhang, Liu, & Jiang, 2014).…”