Origin of high-Mg adakitic magmatic enclaves from the Meichuan pluton, southern Dabie orogen (central China): Implications for delamination of the lower continental crust and melt-mantle interaction

Petrogenesis of the early Cretaceous volcanic rocks in the North Huaiyang tectono-magmatic unit of the Dabie Orogen, eastern China: Implications for crust–mantle interaction

“…As illustrated in Fig. 8, the zircon e Hf (t) values of the Jingangtai volcanic rocks match with those of granites in the Dabie Orogen Zhang et al, 2010a;Xu et al, 2013) and Early Cretaceous intermediat-mafic rocks in the Dabie Orogen (Xu et al, 2012), indicating a genetic relationship between them.…”

“…The large-scale partial melting of the continental crust marks beginning of the extension, while the mafic-ultramafic igneous rocks and alkaline rocks demonstrate the intensive lithospheric thinning and extensional setting in the region. Xu et al, 2012;Zhang et al, 2010a); Early Cretaceous intermediat-mafic rocks in the Dabie Orogen Xu et al, 2012). Table 5.…”

Late Early Cretaceous adakitic granitoids and associated magnesian and potassium‐rich mafic enclaves and dikes in the Tunchang–Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization

“…Petrogenesis 6.1.1. Adakitic rocks via partial melting of newly underplated lower crust Adakitic rocks may be generated by several processes, including (a) melting of subducted young and hot oceanic crust (Mechanism A; Defant and Drummond, 1990;Stern and Kilian, 1996;Martin et al, 2005;Zhou et al, 2006b;Wang et al, 2007aWang et al, , 2008aTang et al, 2010); (b) partial melting of delaminated lower crust (Mechanism B; Rudnick, 1995;Xu et al, 2002a;Gao et al, 2004;Wang et al, 2006aWang et al, , b, 2007bHuang et al, 2008;Zhang et al, 2010); (c) partial melting of subducting continental crust (Mechanism C; Wang et al, 2008b); (d) assimilation and fractional crystallization (AFC) or fractional crystallization (FC) from parental basaltic magmas (Mechanism D; Castillo et al, 1999;Macpherson et al, 2006;Richards and Kerrich, 2007;Li et al, 2009); (e) magma mixing between felsic and basaltic magmas (Mechanism E; Guo et al, 2007;Streck et al, 2007); (f) partial melting of thickened basaltic lower crust (Mechanism F; Atherton and Petford, 1993;Rudnick, 1995;Petford and Atherton, 1996;Chung et al, 2003;Wang et al, 2005aWang et al, , 2007c. Based on petrologic and geochemical observations, we suggest that the first five models are Xu et al (1996Xu et al ( , 1999b and Yu et al (2003).…”

“…In general, adakitic rocks generated by mechanisms A-C have high Mg # values (>0.50) or are similar to high-Mg andesites because their MgO or Mg # values are increased by the interaction between magmas derived from subducted oceanic crust, subducted continental crust or delaminated lower crust and mantle peridotites during magma ascent (Fig. 11b) (e.g., Stern and Kilian, 1996;Rapp et al, 1999;Xu et al, 2002a;Gao et al, 2004;Wang et al, 2006aWang et al, , b, 2007aWang et al, , b, 2008aHuang et al, 2008;Tang et al, 2010;Zhang et al, 2010). However, the Tunchang-Fengmu adakitic granodiorites and granites have low MgO (0.29-2.05 wt.%) or Mg # (0.27-0.50) values (Appendix 5), indicating that interaction between felsic magmas and mantle peridotites was unlikely (Fig.…”

“…However, sources of the mafic and felsic magmas involved in the mixing or mingling process remain unclear. For example, the felsic magmas have been attributed to both supracrustal or lower crustal materials (Koyaguchi and Kaneko, 1999;Bonin, 2004;Guo et al, 2007;Streck et al, 2007) and the mafic magmas have been interpreted as originating directly from the mantle or from mafic lower crust (e.g., Silva et al, 2000;Bonin, 2004;Chen et al, 2009;Zhang et al, 2010). These issues are also directly related to uncertainties concerning the source materials and formation mechanisms of the host granitoids.…”