Laboratoire de Géologie, Ecole Normale Supérieure, PSL Res. Univ., Paris, France.
ISTerre, CNRS, Université Grenoble Alpes, Grenoble, France.
Sci Adv. 2019 Oct 30;5(10):eaax4295. doi: 10.1126/sciadv.aax4295. eCollection 2019 Oct.
Does Earth's mantle drive plates, or do plates drive mantle flow? This long-standing question may be ill posed, however, as both the lithosphere and mantle belong to a single self-organizing system. Alternatively, this question is better recast as follows: Does the dynamic balance between plates and mantle change over long-term tectonic reorganizations, and at what spatial wavelengths are those processes operating? A hurdle in answering this question is in designing dynamic models of mantle convection with realistic tectonic behavior evolving over supercontinent cycles. By devising these models, we find that slabs pull plates at rapid rates and tear continents apart, with keels of continents only slowing down their drift when they are not attached to a subducting plate. Our models show that the tectonic tessellation varies at a higher degree than mantle flow, which partly unlocks the conceptualization of plate tectonics and mantle convection as a unique, self-consistent system.
地幔驱动板块,还是板块驱动地幔流动?然而,这个长期存在的问题可能没有得到很好的提出,因为岩石圈和地幔都属于一个单一的自组织系统。或者,这个问题可以更好地表述为:在长期的构造重组过程中,板块和地幔之间的动力平衡是否会发生变化,以及这些过程在什么空间波长上运行?回答这个问题的一个障碍是设计具有在超大陆周期内演化的现实构造行为的地幔对流动力学模型。通过设计这些模型,我们发现板块以很快的速度拉动板块并撕裂大陆,只有当大陆的地幔没有与俯冲板块连接时,大陆的地幔才能减缓它们的漂移。我们的模型表明,构造镶嵌的变化程度高于地幔流动,这在一定程度上解开了板块构造和地幔对流作为一个独特的、自洽系统的概念化。