A Paradigm Shift: North China Craton's North Margin Orogen Is the Collisional Suture With the Columbia Supercontinent

In a new study, Wu, Wang, Zhou, Zhao, Haproff, et al. (2022, https://doi.org/10.1029/2022GC010662) present a comprehensive study of the North Margin Orogen of the North China Craton (NCC), showing that older accreted rocks in this belt preserve a record of active margin magmatism from 2.2 to 2.0 Ga, followed by collisional tectonics, marked by melange and mylonitic shear zones, then granulite facies metamorphism at 1.9-1.8 Ga, marking the final collision of the NCC with the Columbia Supercontinent. The multidisciplinary studies presented in this work support earlier suggestions that the North China Craton amalgamated during accretionary orogenesis in the Neoarchean to earlier Paleoproterozoic, and that the late widespread 1.85 Ga high-grade metamorphism is craton-wide in scale, and not confined to a narrow orogen in the center of the craton. This new understanding creates new possibilities for refining reconstructions of one of Earth's earliest, best documented supercontinents, showing a globally linked plate network at 1.85 Ga, and suggests drastic new correlations and models for mineral resource exploration.

Automated summary

In a comprehensive study of the North Margin Orogen of the North China Craton, it is shown that the older rocks in this region have preserved evidence of active margin magmatism, collisional tectonics, and granulite facies metamorphism. This study supports the idea that the North China Craton amalgamated during accretionary orogenesis and that the 1.85 Ga high-grade metamorphism is craton-wide in scale. This new understanding has implications for reconstructing Earth's early supercontinents and for mineral resource exploration.