Earth Science Frontiers ›› 2020, Vol. 27 ›› Issue (1): 270-274.DOI: 10.13745/j.esf.2020.1.28

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Is negative buoyancy the primary force driving plate motion during the onset of subduction? A discussion on rock fracture mechanics

ZHOU Hui1,*(), QIU Liang2, YAN Danping2   

  1. 1. The Office of Scientific Research, Peking University, Beijing 100871, China
    2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Beijing), Beijing 100083, China
  • Received:2019-06-02 Revised:2019-10-25 Online:2020-01-20 Published:2020-01-20
  • Contact: ZHOU Hui

Abstract:

Based on the method of rock fracture mechanics, we discussed in this paper the possibility of pulling force (negative buoyancy) exerted by subducting plate being the driving force for plate movement. Experimental results of rock fracture indicate that the lithospheric strength is very low, only about n×10 MPa, which is unlikely to bear the necessary n×10 2 MPa stress during the onset of subduction. In addition, results from tectonic modeling, thermal cracking, fatigue fracture, flexure of subducted slabs, subduction dehydration and melting process studies reveal that the idea of negative buoyancy of subducting plate being the driving force for plate movement is inconsistent with research observations.

Key words: rock fracture mechanics, driving force for plate movement, negative buoyancy, lithosphere strength

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