A paradigm shift: North China Craton’s North Margin Orogen is the
collisional suture with the Columbia Supercontinent
Abstract
In a new study, Wu et al. (this issue) present a comprehensive study of
the North Margin Orogen of the North China Craton, showing that older
accreted rocks in this belt preserve a record of active margin magmatism
from 2.2-2.0 Ga, followed by collisional tectonics, marked by mélange
and mylonitic shear zones, then granulite facies metamorphism at 1.9-1.8
Ga, marking the final collision of the North China Craton with the
Columbia Supercontinent. The multidisciplinary studies present in this
work support earlier suggestions that the North China 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.