Late Paleoproterozoic tectonic evolution of the Olongbuluke Terrane, northern Qaidam, China: Constraints from stratigraphy and detrital zircon geochronology

Stratigraphic Framework of the Cryogenian in China

“…(Lu, 2002;Li et al, 2003a), indicated that Mahuanggou and Kubomu formations may have been deposited during Cryogenian Jiangkou glaciation. However, Shen et al (2010) and Sun et al (2019) confirmed that the diamictite's glaciogenic provenance remains uncertain, and would be deposited in a high energy foreshore or nearshore setting. Therefore, it remains to be proved whether the Quanji Group contains Cryogenian strata.…”

Provenance and tectonic significance of the Zhongwunongshan Group from the Zhongwunongshan Structural Belt in China: insights from zircon geochronology

“…The Neoproterozoic granitic gneiss with similar formation ages was found in the Yuqia-Shaliuhe HP-UHP metamorphic belt, located on the southern margin of the NQSB [3,27]. Due to the continental collision between the Olongbruk Microblock and the Qaidam Block, the most important Neoproterozoic tonalite-monzonitic granites were formed, and intruded into the Yuqia-Shaliuhe HP-UHP metamorphic belt during the Jinningian period (1000-800 Ma) [28,29,36,45]. In addition, the Hf isotopic results showed that the Neoproterozoic zircons from the sample KDLG1505 also had similar model age (2815-1581 Ma, with a peak of 2362 Ma), and a similar origin (dominated by ancient crust melting) as the Neoproterozoic Shaliuhe granitic gneiss in the eastern section of the Yuqia-Shaliuhe HP-UHP metamorphic belt [2,46].…”

“…A previous survey indicated the sustained oceanic crust subduction occurred when the Qaidam block northward dived beneath the Olongbruk Microblock during the Late Ordovician [36,63]. Due to the rapid subduction, the thickened lower continental crust melting took place which formed the active epicontinental arc tonalite-granodiorite (450-440 Ma) in the Tanjianshan ophiolite-volcanic arc belt [3,12,28,51]. As the only Early Paleozoic continental arc granites within the age population in the study area, the Tomorit quartz diorite-monzogranite series approaching to the south of Ulan was another source for the Zhongwunongshan Group.…”

“…During the Late Ordovician to Middle Silurian (465-435 Ma), the North Qaidam Ocean closed and the Qaidam Block collided with the Olongbruk Microblock. Due to the rapid subdution, the thickened lower continental crust melting took place which formed the epicontinental arc tonalites-granodiorites (450-440 Ma) in the Tanjianshan ophiolite-volcanic arc belt [3,12,28]. At the same time, the back-arc basin to the north of the North Qaidam deposited thick flysch sediments in the ZWSB and the adjacent South Qilian area during the Silurian [63].…”

“…Devonian, including the Paleoproterozoic (2400-1800 Ma) continental crust formation [2,28]; Neoproterozoic (1030-750 Ma) magmatic activities related to Rodinia supercontinent convergence and breakup [30,31]; early Paleozoic (542-434Ma) magmatism and HP-UHP metamorphism by oceanic crust subduction followed by collision associated continental deep-subduction [3,32]. The continental deep subduction marked the assembly of Olongbruk Microblock and the Qaidam Block.…”