Early Carboniferous adakite-like and I-type granites in central Qiangtang, northern Tibet: Implications for intra-oceanic subduction and back-arc basin formation within the Paleo-Tethys Ocean

Early Carboniferous continental margin magmatism in central Qiangtang, Tibet: Implications for the geological evolution of the Paleo‐Tethys Ocean

“…Geochemical classification diagrams for the Riwanchaka volcanic rocks: (a) SiO 2 versus Zr/TiO 2 *0.0001 (Winchester & Floyd, ); (b) Th versus Co (Hastie, Kerr, Pearce, & Mitchell, ); and (c) A/NK versus A/CNK (Maniar & Piccoli, ). Literature data are from Dan et al (), Jiang et al (, 2015), Liu et al (); Wang et al (), and Zhai et al (2017) [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…According to recent geological mapping in this area, early Carboniferous magmatic rocks are rarely exposed in the NQ due to the widespread Jurassic to Cenozoic sedimentary cover. However, recent studies have revealed that volcanic rocks are widely distributed in the Riwanchaka area of the SQ, and some coeval intrusive rocks have also been identified in the LSSZ (Hu et al, , ; Liu et al, ; Shi, Dong, & Wang, ; Zhai et al, ).…”

“…These igneous rocks record information regarding subduction and collisional processes, which can constrain the tectonic evolution of the Paleo‐Tethys Ocean and models of the formation and evolution of the Tibetan Plateau. The newly recognized Late Devonian–early Carboniferous magmatic suite was identified from previously published zircon U–Pb ages, and is considered to have formed during the subduction of oceanic crust in the Paleo‐Tethys Ocean (e.g., Jiang et al, ; Li, ; Liu et al, ; Wang et al, ; Zhai et al, ). However, preliminary petrological and geochemical studies have resulted in several petrogenetic and tectonic models being proposed (e.g., Dan et al, ;Jiang et al, ; Wang et al, ).…”

Early Cretaceous Adakitic Rocks in the Northern Great Xing'an Range, NE China: Implications for the Final Closure of Mongol‐Okhotsk Ocean and Regional Extensional Setting

“…However, the Keyihe adakitic rocks have completely negative ε Hf (t) values (Fig. 7), with old T DM2 model ages of zircons (1.77-2.39 Ga), which suggest derivation from partial melting of an isotopically evolved lower crust with no addition of mantle melts (Ma et al, 2013;Liu et al, 2018;Keevil et al, 2019). These further confirms our hypothesis.…”

“…Previous studies proposed that adakites or adakitic rocks can be formed in a variety of origins: (a) partial melting of subducted oceanic crust (Defant and Drummond, 1990;Martin et al, 2005;Wang et al, 2006;Liu et al, 2018); (b) high-pressure fractional crystallization of basaltic melts (Defant and Drummond, 1990;Castillo et al, 1999;Macpherson et al, 2006), (c) partial melting of thickened mafic lower crust (Atherton and Petford, 1993;Wang et al, 2007;Wang et al, 2008;He et al, 2011); (d) the mixing of basic and acidic magmas in the lower crust (Guo et al, 2007;Chen et al 2013a, b); (e) partial melting of delaminated lower crust (Xu et al, 2002;Gao et al, 2004;Xu et al, 2006;Yang et al, 2008;Zhang J et al, 2010). The possibility that partial melting of subducted oceanic crust generated the Early Cretaceous Keyihe adakitic rocks can be ruled based on their geochemical characteristics and the tectonic context of the Erguna block .…”