An early high-pressure history preceeded pelitic ultrahigh-temperature granulite formation in the Tuguiwula area, Khondalite Belt, North China Craton

Petrogenesis of the ~1.94 Ga Meta‐gabbronorites in Liangcheng: Implications for Tectonic Evolution of the Khondalite Belt, North China Craton

“…there existed an early high-pressure history that preceded UHT metamorphism in the region (Liu et al, 2021), which is consistent with the previous studies that the peak highpressure metamorphism occurred at ~1.95 Ga (Zhao et al, 2005;Yin et al, 2014Yin et al, , 2015, whereas the UHT metamorphism occurred at ~1.94-1.92 Ga (Santosh et al, 2007;Li and Wei, 2018;Wang B et al, 2020). Thus the peak high-pressure metamorphism related to orogenic crustal thickening was prior to the UHT metamorphism in the region.…”

“…In addition, high-pressure, high-ultrahigh temperature (UHT) granulites related to the late Paleoproterozoic orogenic events are locally exposed in KB (Zhao et al, 1999(Zhao et al, , 2005Santosh et al, 2006Santosh et al, , 2007Santosh et al, , 2009Santosh et al, , 2012Zhou et al, 2010;Tsunogae et al, 2011;Guo et al, 2012;Liu et al, 2012;Shimizu et al, 2013;Yin et al, 2014;Jiao et al, 2015). The khondalite series are mainly graphite-bearing garnet sillimanite gneiss, sillimanite biotite monzonite gneiss, sillimanite garnet felsic gneiss, garnet quartzite, calcsilicate rocks, and marble (Condie et al, 1992;Lu et al, 1996;Zhao et al, 1999;Xu et al, 2007;Cai et al, 2014). The detrital zircon ages of the khondalite series mainly range from ~2.2 Ga to 2.0 Ga (Wan et al, 2006(Wan et al, , 2009Xia et al, 2006a, b), and they were subjected to metamorphism at ~1.95-1.85 Ga (Zhao et al, 2005;Wan et al, 2006Wan et al, , 2009Xia et al, 2006a, b;Dong et al, 2007;Cai et al, 2014).…”

“…The tectonic regime for the meta-gabbronorites in the eastern segment of the KB is still disputed, as opinions vary from ridge subduction (Peng et al, 2010;Guo et al, 2012;Santosh et al, 2012) to post-collisional mantle upwelling (Zhao, 2009;Zhai and Santosh, 2011;Li and Wei, 2018;Wang B et al, 2020). Previous studies suggest that almost all metamorphic rocks in the eastern segment of KB recorded clockwise P-T-t paths (Jiao et al, 2013b;Yin et al, 2014Yin et al, , 2015Li and Wei, 2018;Wang B et al, 2020;Liu et al, 2021), indicating a continental collisional setting (Zhao et al, 2005). Furthermore, thermodynamic modeling and isotopic geochronology studies revealed Fig.…”

Paleoproterozoic ultrahigh‐temperature mafic granulites with a high‐pressure prograde path from the Alxa Block: Implications on the tectonic evolution of the Khondalite Belt, North China Craton

“…Our study shows that the UHT granulites from the Alxa, Daqingshan, and Jining areas of the KB all experienced a similar metamorphic evolution from HP to UHT (involving decompression with heating and near-IBC; Figure 14a; Li & Wei, 2018;Liu et al, 2021;this study). Existing work suggests that UHT granulites from the eastern part of the KB also record a later decompression stage with cooling (Li & Wei, 2018;Liu et al, 2021) or heating , which may be related to the overprinting of $1.85 Ga granulite facies or UHT metamorphism in the eastern part of the KB (Guo et al, 2012;Peng et al, 2014). By combining our findings with existing petrochronology studies in the KB (e.g., Huang et al, 2019;Li & Wei, 2018;Yin et al, 2014Yin et al, , 2015, a possible geological scenario for the KB includes the following: (1) the protoliths of mafic or pelitic granulites were thickened at lower crustal levels ($45 km depth) at $1.96-1.95 Ga due to collision between the Yinshan and Ordos blocks (e.g., Zhao et al, 2012;Zhao & Zhai, 2013);…”

“…(2) the granulites were exhumed to middle crustal levels ($25 km depth) at $1.92 Ga, mantle-derived mafic magmatism (e.g., mantle upwelling) or radiogenic heating led to UHT metamorphism (e.g., Huang et al, 2019;Peng et al, 2010;Zhao, 2009;Zou et al, 2022); (3) the UHT granulites from the western part of the KB (Alxa and Helanshan area; Gou et al, 2018Gou et al, , 2019Zou et al, 2022; this study) experienced a prolonged cooling process over $110 million years (Ma) ($1.92-1.81 Ga) at middle crustal levels ($25 km deep), whereas the UHT granulites from the eastern part of the KB (Daqingshan and Jining area) were exhumed to shallower depths during cooling (Jining area; Li & Wei, 2018;Liu et al, 2021) or heating (Daqingshan area; after $1.85 Ga.…”