Petrogenesis of continental igneous rocks: Reply to the comment by Qiu et al. on 'Origin of TTG-like rocks from anatexis of ancient lower crust: Geochemical evidence from Neoproterozoic granitoids in South China [Lithos 113 (2009) 347-368]'

摘要

We welcome the comment by Qiu et al. (2010-this issue) on our paper entitled "Origin ofTTG-like rocks from anatexis of ancient lower crust: Geochemical evidence from Neoproterozoic granitoids in South China" (Zhang et al, 2009a). This provides us a good opportunity to highlight important issues concerning the petrogenesis of the Neoproterozoic granitoids in South China. In their comment, Qiu et al. (2010-this issue) claimed that they 'saw' evidence of some juvenile crust derived from the depleted mantle, although our rocks have extremely negative ε_(Nd_(t) and ε_(Hf) values, and argued that the Neoproterozoic granitoids in the Huangling batholith are mantle plume-related. The presence of juvenile crust in magmatic rocks is a key argument for the involvement of mantle plume (Zheng et al., 2008). In order to resolve this question, it is critical to examine whether there is involvement of juvenile crust in the Huangling batholith and whether the mafic rocks in the batholith are mantle plume-related. These issues are of significance because they can help us understand not only the tectonic regime of widespread Neoproterozoic igneous rocks in South China but also the petrogenesis of continental igneous rocks with respect to the nature of crust-mantle interaction. In particular, their comment reminds us that an integrated study of major elements, trace elements, and radiogenic isotopes on the same rocks is necessary when using the compositions of mafic to felsic rocks to decipher the nature of their source.