Reviewing subduction initiation and the origin of plate tectonics:What do we learn from present-day Earth?

作者：Gang Lu,Liang Zhao,Ling Chen,Bo Wan,FuYuan Wu

摘要：The theory of plate tectonics came together in the 1960s,achieving wide acceptance after 1968.Since then it has been the most successful framework for investigations of Earth’s evolution.Subduction of the oceanic lithosphere,as the engine that drives plate tectonics,has played a key role in the theory.However,one of the biggest unanswered questions in Earth science is how the first subduction was initiated,and hence how plate tectonics began.The main challenge is how the strong lithosphere could break and bend if plate tectonics-related weakness and slab-pull force were both absent.In this work we review state-of-the-art subduction initiation(SI)models with a focus on their prerequisites and related driving mechanisms.We note that the plume-lithosphere-interaction and mantleconvection models do not rely on the operation of existing plate tectonics and thus may be capable of explaining the first SI.Reinvestigation of plate-driving mechanisms reveals that mantle drag may be the missing driving force for surface plates,capable of triggering initiation of the first subduction.We propose a composite driving mechanism,suggesting that plate tectonics may be driven by both subducting slabs and convection currents in the mantle.We also discuss and try to answer the following question:Why has plate tectonics been observed only on Earth?

發文機構：State Key Laboratory of Lithospheric Evolution

關鍵詞：subductioninitiationplatetectonicsmantleconvectiondrivingforcemantledrag

分類號： P54[天文地球—構造地質學]