Melting of continental crust during subduction initiation: A case study from the Chaidanuo peraluminous granite in the North Qilian suture zone

Geochronology and petrogenesis of Neoproterozoic S‐type granites from the Qilian Block, north‐west China, and their geological implications

“…The tectonic setting of strongly peraluminous, S‐type granites continues to be the subject of debate. Potential tectonic settings that have been previously proposed are (1) subduction‐related setting such as a back‐arc setting (Collins & Richards, ; Wang et al, ), ridge subduction (Cai et al, ), or initiation of subduction (Chen, Song, Niu, & Wei, ); and/or (2) continental collision‐related settings, such as syn‐collisional or post‐collisional settings (Finger, Roberts, Haunschmid, Schermaier, & Steyrer, ; Sylvester, ; Yang et al, ). However, in this study, we suggest continental margin arc setting to be the most probable tectonic environment for the peraluminous granites in the east of the QB, on the basis of the following evidence.…”

Garnet effect on Nd-Hf isotope decoupling: Evidence from the Jinfosi batholith, Northern Tibetan Plateau

“…The Jinfosi batholith is one of the largest batholiths in the NQOB, considered as typical products of intra-crustal differentiation in a syn/post-collisional setting (Hu et al, 2006;Zhang et al, 1995;Wu et al, 2010;Song et al, 2013 (Wang et al, 2005;Chen et al, 2014), generally coupled with the subduction-related HP metamorphic activities (489-440 Ma) (Wu et al, 1993;Zhang et al, 1997Song et al, 2004Song et al, , 2006Liu et al, 2006). The Jinfosi batholith is ~ 60 km long and 10-12 km wide, extending in NW-direction in the northwestern part of the NQOB (Fig.…”

Petrogenesis of the early Paleozoic low-Mg and high-Mg adakitic rocks in the North Qilian orogenic belt, NW China: Implications for transition from crustal thickening to extension thinning

“…The subduction polarity of the Qilian ocean is still controversial, most researchers suggested a double subduction model (Zuo and Liu, 1987;Wu et al, 2009Wu et al, , 2010Zhang et al, 2012), and some argued for north-dipping subduction (Xu et al, 1994;Xia et al, 1996Xia et al, , 1998Xia et al, , 2003Zhang et al, 1997bZhang et al, , 1998Song et al, 2013) or south-dipping subduction (Song, 1997;Sobel and Arnaud, 1999;Gehrels and Yin, 2003;Yin et al, 2007). The subduction of the Qilian ocean was probably initiated at $520 Ma as marked by the earliest arc magmatism ($515 Ma), ''infant arc'' boninitic complex ($517 Ma) and HP/LT metamorphic rocks ($490 Ma) Wu et al, 2010;Song et al, 2013;Chen et al, 2014). In the North Qilian, voluminous The field for subducted continental crustd-erived adakites, and delaminated or thickened lower crust-derived adakitic rocks after Wang et al (2006aWang et al ( ,b, 2007Wang et al ( , 2008a widespread granitoids with distinct geochemical character have been recognized, ranging from 520 to 380 Ma, which could provide vital clues for reconstruction the tectonic framework of subduc tion-accretion/collisional orogen.…”

“…During the early-stage (516-505 Ma) most granitoids (e.g., the Chaidanuo and Yemazui granite pluton) have S-type features with negative e Nd (t) and e Hf (t), probably originated from partial melting of the continental materials of the Qilian block (Wu et al, 2010;Chen et al, 2014). Nearly at the same time, Wu et al (2010) reported plagiogranite at Kekeli area with age of $512 Ma, probably derived from partial melting of subducted oceanic crust.…”