Recycling of oceanic crust from a stagnant slab in the mantle transition zone: Evidence from Cenozoic continental basalts in Zhejiang Province, SE China

Deciphering the origin of the Cenozoic intracontinental rifting and volcanism in eastern China using integrated evidence from the Jianghan Basin

“…Previous studies on the Cenozoic basalts from the eastern SCB suggested negligible crustal contamination (Li et al, 2015b(Li et al, , 2016bLiu et al, 2016;Chu et al, 2017;Zeng et al, 2017). Trace element compositions of the Jianghan basalts also show no obvious imprint of continent crust in the spidergram (e.g., depletions in Nb and Ta; Rudnick and Gao, 2003) (Fig.…”

“…9 shows chondrite-normalized rare earth element (REE) patterns and primitive-mantle normalized multi-elements spidergram of the Jianghan basalts. As with the basalts from the eastern SCB (Li et al, 2015b(Li et al, , 2016bLiu et al, 2016;Chu et al, 2017;Zeng et al, 2017), all the Jianghan basalts are characterized by OIB-like trace element patterns, being progressively more enriched in the more incompatible elements. Importantly, the late phase basalts are generally more enriched in incompatible trace elements and have higher [La/Yb] N ratios (5.50-10.29, N denotes normalization to primitive mantle) than the early phase basalts ([La/Yb] N = 3.35-4.99).…”

“…The results of the major and trace elements, and Sr-Nd-Hf isotopic analyses of the Jianghan basalts are given in Table S2-S3 (Appendix A). Samples from this study are plotted together with the Cenozoic basalts from the eastern SCB for comparison (Li et al, 2015b(Li et al, , 2016bLiu et al, 2016;Chu et al, 2017;Zeng et al, 2017).…”

“…Although extensive research has focused on the origin of the widespread Cenozoic rifting and volcanism in eastern China (e.g., Flower et al, 2001;Ren et al, 2002;Liu et al, 2004;Niu, 2005;Tang et al, 2006;Xu, 2007;Li et al, 2010Li et al, , 2013Li et al, , 2015bLi et al, , 2016bYin, 2010;Zhao et al, 2011;Xu et al, 2012;Suo et al, 2012Suo et al, , 2014Kuritani et al, 2013;Sakuyama et al, 2013;Gong and Chen, 2014;Wang et al, 2015;Zhao et al, 2016;Chen et al, 2017;Sun et al, 2017), controversy remains and two alternative models are currently invoked. These two competing models have evoked fundamentally different lithospheric and asthenospheric processes as they involve different driving forces ( Fig.…”

“…2B and C). The passive rifting and upwelling model states that the retreat of subduction zone causes the lithosphere of eastern China to extend (Niu, 2013), inducing asthenospheric mantle to upwell and melt (Xu et al, 2012;Li et al, 2015b). Therefore, its driving force is the rollback of the subducted Pacific slab (Niu, 2013).…”