地学前缘 ›› 2020, Vol. 27 ›› Issue (1): 270-274.DOI: 10.13745/j.esf.2020.1.28

• 非主题来稿选登 • 上一篇    下一篇

负浮力是板块运动的驱动力吗?关于岩石断裂力学的讨论

周辉1,*(), 邱亮2, 颜丹平2   

  1. 1.北京大学 科学研究部, 北京 100871
    2.中国地质大学(北京) 地质过程与矿产资源国家重点实验室, 北京 100083
  • 收稿日期:2019-06-02 修回日期:2019-10-25 出版日期:2020-01-20 发布日期:2020-01-20
  • 通讯作者: 周辉
  • 作者简介:周 辉(1968—),男,博士,研究员,主要从事科技管理工作,研究方向为大地构造学。E-mail: zhouhui@pku.edu.cn
  • 基金资助:
    国家自然科学基金项目(41672216);国家自然科学基金项目(41702207)

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

摘要:

本文从岩石断裂力学的角度,讨论了俯冲板块下拉牵引力(负浮力)作为板块运动初始驱动力的可能性。笔者总结已发表的岩石抗张强度的岩石力学实验结果,并和现在普遍认为的负浮力的数量级进行对比分析,结果表明大洋岩石圈上部岩石强度较低,仅有n×10 MPa。虽然随着温度和压力的增加岩石圈的强度不断增强,但是在板块俯冲的初始阶段,大洋岩石圈可能无法承受拖曳板块运动高达n×102 MPa的应力。此外,构造模拟、热开裂、疲劳断裂、俯冲挠曲、俯冲脱水以及熔融作用等地质现象的分析,也表明俯冲板块的负浮力作为板块运动初始驱动力是不符合客观事实的。

关键词: 岩石断裂力学, 板块运动驱动力, 负浮力, 岩石圈强度

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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