Ultramafic–mafic mélange, island arc and post-collisional intrusions in the Mayile Mountain, West Junggar, China: Implications for Paleozoic intra-oceanic subduction–accretion process

Geochemistry, zircon U–Pb ages and Lu–Hf isotopes of early Paleozoic plutons in the northwestern Chinese Tianshan: Petrogenesis and geological implications

“…Definitely, calc-alkaline island-arc igneous rocks of middle-late Ordovician developed in the Suyuenka Complex in Ebinur terrane (Buckman and Aitchison, 2004). Moreover, calc-alkaline late Cambrian (493-501 Ma) and early Ordovician (448-488 Ma) intrusive rocks have been discovered in the southwest West Junggar (Xu et al, 2012). These rocks show strong island arc affinities and are most likely related to subduction of the Junggar Ocean (Xu et al, 2012).…”

“…Moreover, calc-alkaline late Cambrian (493-501 Ma) and early Ordovician (448-488 Ma) intrusive rocks have been discovered in the southwest West Junggar (Xu et al, 2012). These rocks show strong island arc affinities and are most likely related to subduction of the Junggar Ocean (Xu et al, 2012). Because these calc-alkaline rocks occur in the northern side of the Neoproterozoic to early Paleozoic Tangbale and Mayile ophiolites and gabbros that yielded zircon ages of 531 ± 15 Ma and 572 ± 9 Ma, respectively (Jian et al, 2005;Yang et al, 2012), it is suggested that the beginning of northward subduction of the Junggar Ocean likely began in the late Cambrian.…”

A Late Carboniferous–Early Permian slab window in the West Junggar of NW China: Geochronological and geochemical evidence from mafic to intermediate dikes

“…The tectonic setting of West Junggar has long been controversial, such as a post-collisional environment since the Early Carboniferous (Chen and Arakawa, 2005;Chen and Jahn, 2004;Fan et al, 2007;Han et al, 1997Han et al, , 2006Su et al, 2006;Xu et al, 2012), or a subduction setting in the Late Carboniferous (Geng et al, 2009;Ma et al, 2012;Tang et al, 2010Tang et al, , 2012aXiao et al, 2008Xiao et al, , 2009Yang et al, 2012;Yin et al, 2010;Zhang et al, 2011a,b). Based on the occurrence of the I-type and A-type granites and their undeformed and alkali-enriched characteristics, most granitic plutons in West Junggar were previously interpreted as post-collisional granites (Chen and Jahn, 2004;Xu et al, 2012). A post-collisional tectonic setting was considered to have begun at 340 Ma (Chen and Jahn, 2004;Han et al, 1997Han et al, , 2006.…”

“…In West Junggar, a Late Carboniferous magmatic association of various volcanic and intrusive rocks have extensively developed and mostly derived from a mantle magmatic source (Chen and Arakawa, 2005;Chen and Jahn, 2004;Fan et al, 2007;Geng et al, 2009Geng et al, , 2011Han et al, 2006;Tang et al, 2010;Xu et al, 2012;Yin et al, 2010;Zhang et al, 2011a,b). Zhang et al (2011a,b) first discovered some Late Carboniferous N-MORB to OIB-like tholeiitic and alkaline basalts in Yeyagou (306 Ma) and Maliya (311 Ma) and suggested different derivations from various enriched mantle source associated with ridge-trench interaction (Zhang et al, 2011a,b).…”

“…Previous studies mainly focused on the petrology, geochemistry and geochronology of granitic plutons (e.g. A-type granites and adakites) whereas the petrogenesis of mantle-derived magmatic rocks in West Junggar is still poorly constrained (Chen and Arakawa, 2005;Chen and Jahn, 2004;Fan et al, 2007;Geng et al, 2009Geng et al, , 2011Han et al, 2006;Tang et al, 2010;Xu et al, 2012;Yin et al, 2010;Zhang et al, 2011a,b). Mafic to intermediate dikes are Geng et al, 2009;Yin et al, 2010).…”