The assembly and breakup of supercontinents is the self-expression of plate tectonics.The assembly stage is accompanied by global-scale subduction and collisional orogeny,while the fragmentation stage produces large-scale mafic magmatic events.The Columbia supercontinent was the first true supercontinent in Earth's history,and its main body coalesced between 2.1～1.8 Ga and finally broke apart at 1.3 Ga.Compared with the other younger supercontinents,the paleogeographic reconstruction model of the Columbia supercontinent still remains quite uncertain,which profoundly influences our understanding of the geodynamic processes and effects of its breakup.In this study,based on the correlation of global Paleo-Mesoproterozoic mafic magmatism events,integrated with the published work and analysis of global igneous rock geochemical data,we proposed that multiple Paleo-Mesoproterozoic mantle plume events resulted in the incomplete breakup of the Columbia supercontinent,which significantly affected the geochemical compositions and topographic height of the continental crust at that time.Highly differentiated continental crust and low topographic height together greatly reduced the flux of nutrients into the ocean by weathering and denudation of continental crust materials,thus limiting the primary productivity of marine organisms,and ultimately stalling the evolution of life during the transition period from the Colombian supercontinent to the Rodinia supercontinent.
关键词
哥伦比亚超大陆/不彻底裂解/地幔柱/古—中元古代
Key words
Columbia supercontinent/Incomplete breakup/Mantle plumes/Paleo-Mesoproterozoic
维普
万方数据