Precambrian mafic dyke swarms in the North China Craton and their geological implications

A map of major Precambrian mafic dyke swarms and related units in the North China Craton is compiled, and the features and geological implications of these swarms are demonstrated. The Archean dyke swarms are available to portray the early crustal growth and cratonization. The middle Paleoproterozoic (2200-1850 Ma) swarms and related magmatic series could constrain the tectonic evolution: They approve that the craton was amalgamated by two sub-cratons. The late Paleoproterozoic (1800-1600 Ma), Mesoproterozoic (1400-1200 Ma) and Neoproterozoic (1000-800 Ma) series swarms are important in paleogeographic reconstruction: they indicate that North China might have connected with some of the North European and North American cratons during Proterozoic. Dyke swarms are not only geological timescales and tectonic markers but also evolution indicators of lithospheric mantle: they imply a rejuvenation of the sub-continental lithospheric mantle of North China at 1780-1730 Ma. These swarms occurred with several rifts, including the Hengling (2200-1970 Ma), Xuwujia (1970-1880 Ma), Xiong'er (1800-1600 Ma), Yan-Liao (1730-1200 Ma), and Xu-Huai (1000-800 Ma). Among them, the Xuwujia rift was possibly continental arc associated; whereas the others were intra-continental. In addition, the Xiong'er and Xu-Huai rifts were possibly triple junctions along the present southern and southeastern margins of the Craton, respectively. Different tectonic settings of these rifts and dyke swarms would result in diversified series of ore deposits.