The metamorphic ages of the mafic granulites were not obtain

The metamorphic ages of the mafic granulites were not obtained in this study because of lacking of zircon crystals. Due to the stronger retrograde metamorphism, the peak metamorphic conditions of the felsic rocks are hardly acquired. Taking into consideration the occurrence of mafic granulites as small lenses in the felsic granulites and leucogranites (Fig. 3), both rocks are inferred to have undergone similar metamorphic history. This argument is supported by the petrologic observations mentioned above that the felsic and mafic rocks underwent granulite facies metamorphism, together with the leucogranites (Fig. 3). The entire high-grade metamorphic complexes within the Tongka village (Figs. 2 and 3) are thus argued to experience high-pressure granulite facies metamorphism with pressure up to 17 kbar at 924 ± 34 Ma. If the argument is reasonable, the metamorphic conditions of the Tongka granulites are similar to those of the Himalayan granulites (e.g., Davidson et al., 1997; Liu and Zhong, 1997; Neogi et al., 1998; Daniel et al., 2003; Liu et al., 2007a; b), suggesting that crustal thickening during Neoproterozoic, probably in a scene similar to that of the present day southern Tibetan plateau. Within the southern Qiangtang terrane, low-grade meta-sandstones were intruded by deformed Ordovician granitic bodies (Pullen et al., 2011; Zhao et al., 2014). The meta-sandstones were therefore regarded as the basement of the southern Qiangtang terrane (e.g., Pullen et al., 2011; Pullen and Kapp, 2014). Recent studies have revealed that the meta-sandstones are the late of aldehyde dehydrogenase inhibitor age (Yang et al., 2014) and were named as the Rongma Formation (Fig. 1, Yang et al., 2014). Moreover, recent detrital zircon studies of meta-sedimentary rocks have clearly shown a dominant age peak of ∼950 Ma in the southern Qiangtang terrane (e.g., Gehrels et al., 2011; Pullen et al., 2011; Zhu et al., 2013; Yang et al., 2014), suggesting an older crystalline basement beneath the southern Qiangtang terrane (e.g., Zhu et al., 2013; Yang et al., 2014). Moreover, Zhu et al. (2013) further argued the age obtained from zircon grains from the southern Qiangtang terrane are similar to those from the Eastern Ghats province India and the Rayner province of East Antarctica. The age data from zircon grains in the granulites reported in this study (Figs. 9 and 10, Table 2) correlate with their source from the low-grade metasedimentary rocks of the southern Qiangtang terrane (e.g., Gehrels et al., 2011; Pullen et al., 2011; Zhu et al., 2013; Yang et al., 2014). Therefore, the granulites within the Tongka village could represent the basement of the southern Qiangtang terrane. The late Cambrian meta-sandstones (Pullen et al., 2011; Yang et al., 2014) are cover strata rather than the basement of the southern Qiangtang terrane, structurally overlying the high-grade crystalline basement. Based on the geochronological and petrological observations in this study, the Tongka high-grade complex can be further correlated to the Eastern Ghats-Rayner provinces (e.g., Dobmeier and Raith, 2003; Veevers, 2007; Li et al., 2008; Chatterjee et al., 2010; Corvinoa et al., 2011), and we propose a simply tectonic model to explain the evolution of the southern Qiangtang terrane (Fig. 11). During the Rodinian supercontinent assembly, a vast intercontinental collisional belt existed between the Greater India and eastern Antarctica (Fig. 11). The southern Qiangtang terrane, Eastern Ghats, as well as the Rayner belt were parts of this belt. This implies that some portions of the Rodinian supercontinent are high plateau, similar to the Tibetan plateau today. After Rodinian supercontinent breakup, the southern Qiangtang terrane was located in the margin of Gondwana supercontinent, and was covered by late Cambrian sandstones, regarded as Rongma Formation (Fig. 1, Yang et al., 2014). During the breakup of the Gondwana supercontinent, the southern Qiangtang terrane moved northwards, and was incorporated in the formation of Tibetan plateau during the Cenozoic times.