Genesis and tectonic significance of Mesoproterozoic A-type granites in North China Craton
The North China Craton preserves Mesoproterozoic magmatic records related to the breakup of the Columbia supercontinent.In this paper,the temporal and spatial distribution,petrological and geochemical characteristics of the A-type granites in the main rifts and their surrounding areas of the North China Craton in the Mesoproterozoic are reviewed.The genesis and tectonic background of the A-type granites in each period are discussed,and their indicative significance for the breakup events of the North China Craton in the Mesoproterozoic is discussed.Four stages of A-type granites are mainly developed in the North China Craton:1)～1.78 Ga A-type granites are mainly distributed in the Xiong'er Rift and Shanxi-Shaanxi area;2)～1.70 Ga A-type granites are mainly distributed in the northern Zha'ertai-Bayan Obo and Yanliao rifts;3)～1.60 Ga A-type granites are mainly distributed in the southern Xiong'er Rift;4)～1.32 Ga A-type granites are mainly distributed in the northern Zha'ertai-Bayan Obo and Yanliao rifts.These four A-type granites are derived from the partial melting of crustal materials,which may be related to the heat source provided by the crustal melting of magma underplating caused by the same period of extension.As a whole,there is an evolution sequence from post-orogenic extension to intracontinental rift environment,and there are obvious spatial and temporal differences in the region.The A-type granites of the Mesoproterozoic in the North China Craton recorded four major breakup events,providing evidence that the North China Craton might have participated in the breakup of the Columbia supercontinent.
Columbia supercontinentA-type graniteNorth China CratonMesoproterozoicTectonic background
万方数据
维普
