Early Carboniferous intra-oceanic arc and back-arc basin system in the West Junggar, NW China

Spatial–temporal framework for the closure of the Junggar Ocean in central Asia: New SIMS zircon U–Pb ages of the ophiolitic mélange and collisional igneous rocks in the Zhifang area, East Junggar

“…By combining the ages of the syn-collisional West Hill quartz diorite (348 Ma) and Hongliuxia ductile shear zone (344 Ma), it is suggested that Junggar Ocean was closed before 343-329 Ma in the Early Carboniferous and the closure is possibly scissors-like from the Zhifang-Kalamaili area in the eastern segment to the Darbute-Karamay area in the western segment. (Zhang et al, 2006a;Geng et al, 2009;Tang et al, 2010), which were interpreted as products of slab or ridge subduction at island arc setting by some researchers (e.g., Zhang et al, 2006a;Shen et al, 2009Shen et al, , 2010Shen et al, , 2012bShen et al, , 2014Geng et al, 2009Geng et al, , 2011Tang et al, 2010Tang et al, , 2012bGao et al, 2013Gao et al, , 2014. However, igneous rocks with arc geochemical signatures may be formed in late-and post-collision settings as well (Harris et al, 1986;Chung et al, 2005;Guo et al, 2005;Mo et al, 2008 porphyry district (Cao et al, 2014aWu et al, 2015).…”

Geochemical, Sr–Nd–Pb and zircon U–Pb–Hf isotopic constraints on the Late Carboniferous back-arc basin basalts from the Chengjisihanshan Formation in West Junggar, NW China

“…The Heishantou Formation, mainly distributed on Barleik Mountain, consists of volcaniclastic rocks, clastic rocks and Nb-enriched basalts and basaltic andesites (Li et al 2014). The Baogutu Formation is composed of deep-sea facies fine-grained clastic rocks consisting of siliceous and muddy siltstone, tuffaceous siltstone, felsic tuff, variegated chert, limestone and basic to intermediate volcanic rocks with zircon U-Pb ages of c. 346-324 Ma (Guo et al 2010;Geng et al 2011;Shen et al 2013;Yang et al 2016). Previous studies have confirmed that the volcanic rocks within the Baogutu Formation distributed in the northern Karamay region possess alkaline oceanic island basalt characteristics (c. 346 Ma; Yang et al 2016), and~324 Ma tholeiites erupted in the Hatu region were reported to have BABB affinity (Shen et al 2013).…”

“…The Baogutu Formation is composed of deep-sea facies fine-grained clastic rocks consisting of siliceous and muddy siltstone, tuffaceous siltstone, felsic tuff, variegated chert, limestone and basic to intermediate volcanic rocks with zircon U-Pb ages of c. 346-324 Ma (Guo et al 2010;Geng et al 2011;Shen et al 2013;Yang et al 2016). Previous studies have confirmed that the volcanic rocks within the Baogutu Formation distributed in the northern Karamay region possess alkaline oceanic island basalt characteristics (c. 346 Ma; Yang et al 2016), and~324 Ma tholeiites erupted in the Hatu region were reported to have BABB affinity (Shen et al 2013). The Xibeikulasi Formation, conformably overlying the Baogutu Formation on the southern side of the Hongshan pluton (Li et al 2010), is characterized by conglomerate, pebbly sandstone and coarse sandstone, representing coarse debris flow deposits (BGMRXUAR, 1993;Li et al 2010).…”

Geochemistry, Petrology, and U–Pb dating of high‐K volcanic rocks in wells WC‐1 and Y‐2 from the northern Junggar Basin, northwestern China: Implications for the closure of the Keramaili oceanic basin during the Carboniferous

“…The extensive distribution of Carboniferous volcanic rocks not only suggests multiple subduction regimes during the Carboniferous, but also provides significant insights into the construction of Carboniferous tectonic models and the depositional filling process (Geng, Sun, Yuan, Zhao, & Xiao, ; D. Li, He, Santosh, & Tang, ; G. Yang et al, ). Interestingly, previous studies suggest different tectonic environments in different regions of the Junggar area since the Carboniferous Period, such as intraoceanic arc in the West Junggar area (Shen et al, ; M. Yang, Wang, & Zheng, ), continental margin arc in the East Junggar area during Early Carboniferous (S. Han, Sang, et al, ; Y. Han, Zhao, et al, ), and postcollision in the east Luliang Uplift during Late Carboniferous (Mao et al, ; Wu, Liu, & Li, ; Wu, Liu, Wei, Li, & Li, ; X. Zhao et al, ). Recently, some researchers proposed that during the Carboniferous, the Keramaili oceanic basin might have experienced a scissor‐type closure from the Keramaili area in the eastern Junggar area to Shiyingtan area in the Western Junggar area (S. Han et al, ; D. Li, He, Tang, Fang, & Kong, ).…”

“…Yang et al, 2011). Interestingly, previous studies suggest different tectonic environments in different regions of the Junggar area since the Carboniferous Period, such as intraoceanic arc in the West Junggar area (Shen et al, 2013; M. Yang, Wang, & Zheng, 2006), continental margin arc in the East Junggar area during Early Carboniferous (S. Han, Sang, et al, 2015; Y. Han, Zhao, et al, 2015), and postcollision in the east Luliang Uplift during Late Carboniferous (Mao et al, 2010;; Wu, Liu, Wei, ; X.…”