Early Jurassic high-pressure metamorphism of the Amdo terrane, Tibet: Constraints from zircon U–Pb geochronology of mafic granulites

Zircon U–Pb age and Hf isotopic compositions of Mesozoic granitoids in southern Qiangtang, Tibet: Implications for the subduction of the Bangong–Nujiang Tethyan Ocean

“…Zhang et al, 2012;Guynn et al, 2013;Zhang et al, 2014) and associated granitic magmatism (Xu et al, 1985;Guynn et al, 2006). During the Middle to Late Jurassic times, the subduction of the BNT near Gaize, Bangong Co and Murghab formed the 170-150 Ma granitoids (Schwab et al, 2004;Li et al, 2014;Liu et al, 2014).…”

Underplating of basaltic magmas and crustal growth in a continental arc: Evidence from Late Mesozoic intermediate–felsic intrusive rocks in southern Qiangtang, central Tibet

“…Nevertheless, it should be noted that this 170-102 Ma continental arc is younger than the arc proposed by Guynn et al (2006) on the basis of the 185-170 Ma granitoids from the Amdo area. In fact, the Amdo block has been interpreted as an isolated microcontinent in the Tethyan Ocean that experienced complex tectono-thermal events, such as Jurassic (~190-170 Ma) highpressure granulite-facies metamorphism (e.g., Guynn et al, 2013;Zhang et al, 2012bZhang et al, , 2014b. Therefore, the coeval (Early Jurassic) magmatism in the Amdo microcontinent may have been related to deep subduction of this microcontinent beneath southern Qiangtang in a collisional setting rather than to northward subduction of the Bangong-Nujiang Ocean (e.g., Guynn et al, 2013;Zhang et al, 2012bZhang et al, , 2014b.…”

“…In fact, the Amdo block has been interpreted as an isolated microcontinent in the Tethyan Ocean that experienced complex tectono-thermal events, such as Jurassic (~190-170 Ma) highpressure granulite-facies metamorphism (e.g., Guynn et al, 2013;Zhang et al, 2012bZhang et al, , 2014b. Therefore, the coeval (Early Jurassic) magmatism in the Amdo microcontinent may have been related to deep subduction of this microcontinent beneath southern Qiangtang in a collisional setting rather than to northward subduction of the Bangong-Nujiang Ocean (e.g., Guynn et al, 2013;Zhang et al, 2012bZhang et al, , 2014b. Late Mesozoic magmatism in the region has been widely attributed to the northward subduction of the Bangong-Nujiang oceanic lithosphere (Geng et al, 2011;Li et al, 2013Li et al, , 2014aLiu et al, 2014).…”

Late Triassic island-arc–back-arc basin development along the Bangong–Nujiang suture zone (central Tibet): Geological, geochemical and chronological evidence from volcanic rocks

“…The Amdo terrane is situated on the suture between the Lhasa terrane to the south and the Qiangtang terrane to the north. Previous investigations have suggested that the Amdo terrane was an isolated microcontinent during the Permian-Triassic and subjected to northward subduction in the Early Jurassic (e.g., Coward et al, 1988;Zhang et al, 2014), indicating that the middle Bangong-Nujiang Tethys has been subjected to different geological evolution during the Mesozoic.…”

“…During the Permian-Triassic, the Amdo terrane is thought to be an isolated microcontinent (e.g., Coward et al, 1988;Shi et al, 2012bShi et al, , 2013Zhang et al, 2014). However, Early-Middle Jurassic peak HP metamorphism (ca.…”