Development of the North China Craton during the Late Archaean and its Final Amalgamation at 1.8 Ga: Some Speculations on its Position Within a Global Palaeoproterozoic Supercontinent

Abstract

New data obtained over the past few years indicate that, by the end of the Archaean, the North China Craton consisted of two major crustal entities, identified as the eastern and western blocks. The formation of island and magmatic arcs along the western margin of the eastern block record the latest Archaean events so far identified. The location of the western block at this time is unknown, however, the occurrence of Palaeoproterozoic passive margin sediments, similar in age to those occurring in the eastern block, indicates essentially similar conditions and possible separation by an ocean of unknown dimensions. Re-initiation of east-dipping subduction beneath the western margin of the eastern block resulted in closure of this Palaeoproterozoic ocean, bringing the western block into dose proximity. Continued subduction resulted in a major continental-continental collision and the western margin of the eastern block was again reactivated, leading to extensive thrusting, high-pressure metamorphism and the generation of crustal melts. This occurred between 1.88 and 1.79 Ga ago, resulting in the formation of the Trans-North China Orogen and final amalgamation of the North China Craton. Although information is sparse to non-existent, we have reviewed the possible location of the North China Craton at the time of collision and note a similarity in terms of age, lithology and distribution of major crustal components between the North China Craton and Baltica. Although speculative, we present this model in the hope that it will stimulate debate and lead to further research in these areas.