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Intraplate Extensional Magmatism of North China Craton and Break-up of Three Supercontinents and Their Deep Dynamics

YAN Guo-han1, CAI Jian-hui1,2, REN Kang-xu1,3, HE Guo-qi1, MU Bao-lei1,Xu Bao-liang1, LI Feng-tang1, Yang Bin1   

  1. 1.The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education,School of Earth and Space Sciences, Peking University, Beijing 100871, China;2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;3. Research Institute of Exploration and Development,Tarim Oilfield Company,PetroChina, Korla 841000, China)
  • Received:2007-06-20 Revised:2007-06-20 Online:2007-06-20 Published:2007-06-20

Abstract: Based on authers' twenty years research on isotope geochronology and spatial distribution of intraplate extensional magmatic rocks (such as alkaline intrusives etc. ) in North China Craton, as well as the existing references, this paper suggests that intraplate extensional magmatisms of North China Craton were concentrated in three stages: the latest Paleoproterozoic-early Mesoproterozoic era(1 850~1 600 Ma), the middle-late Neoproterozoic era(900~600 Ma)and the latest Palaeozoic-Cenozoic era(250 Ma~now), respectively, as named the first, the second and the third extensional stage. The appearance frequency and the spatial distribution of the three stages extensional magmatisms are distinctly different from each other. The third stage has the highest appearance frequency and widest distribution, and the first stage takes second place. It must be especially emphasized that the isochron ages of the three stages magmatic rocks are basically coincident with the break-up timings of Columbia, Rodinia and Pangaea supercontinents,respectively, showing different degrees of response of North China Craton to the break-up of related supercontinents. The activities of super mantle hot plumes are popularly considered as the deep geodynamics of dispersal of supercontinents. So it is speculated that the distance from North China Craton to the center of super mantle hot plume activities in the third extensional stage was the nearest, and that in the second stage was the farthest.