Palaeoproterozoic tectonic history of the North China craton: a review

The continental crust of the North China craton (NCC) is considered to have formed largely by the end of the Neoarchaean, with only local Proterozoic igneous and sedimentary activity recorded. However, Palaeoproterozoic metamorphic events are widespread and rocks within localised mobile zones, including the Liaoji Belt in NE China, the Fengzhen Belt in the northwestern NCC and the Jinyu Belt in the centralwestern NCC, evolved in intracratonic or continental margin settings at ca. 2350-1970Ma. These rocks underwent amphibolite to granulite facies metamorphism, and were intruded by granites at 2150-1950. Another important Palaeoproterozoic tectonothermal event occurred at ca. 1900-1800Ma, resulting in a strong metamorphic and geochronological record in almost all earlier Precambrian rocks in the NCC. This event is traditionally named the Luliang Movement and has previously been considered to mark carbonisation of the NCC. This was closely followed at ca. 1800-1650 Ma by a period of continental rifting and anorogenic magmatic activity. In the rifts, volcano-sedimentary rocks of the Changcheng and Xiong'er Systems overlie earlier Precambrian basement, accompanied by coeval anorogenic magmatism including gabbro-anorthosite-rapikivi intrusions. Mafic dyke swarms of this age are also widely distributed in the NCC and these are characterised by enriched mantle epsilon(Nd)(T) values. Some researchers consider that the 1900-1800 Ma metamorphic event represents continental collision, with the 1800-1650 Ma rifting event involving subsequent extension. Conversely, other workers have suggested that they represent a single event related to Palaeo-Mesoproterozoic mantle upwelling and supercontinent break-up. Controversy also exists as to whether high-pressure granulite to retrogade eclogite facies metamorphism in the NCC was Neoarchaean or Palaeoproterozoic in age. We favour carbonisation of the NCC at ca. 2500 Ma, followed by its involvement in a global pre-Rodinian supercontinent at ca. 2000 Ma. The important Luliang Movement between 1900 and 1650 Ma is considered to be related to break-up of the pre-Rodinian supercontinent. We note, however, that there is currently insufficient evidence to substantiate this model. (C) 2002 Published by Elsevier Science B.V.