Oceanic Plateau and Subduction Zone Jump: Two‐Dimensional Thermo‐Mechanical Modeling

作者：Zhiyong Yan, Lin Chen, Xiong Xiong, Bo Wan, Houze Xu · 发表于：Journal of Geophysical Research Solid Earth · 年份：2021 · DOI：10.1029/2021jb021855 · 被引用次数：31 · 研究领域：Geological and Geochemical Analysis、High-pressure geophysics and materials、earthquake and tectonic studies

Abstract Oceanic plateaus are characterized by overthickened crust and rheologically strong and chemically depleted mantle root with respect to normal oceanic lithosphere. The buoyant nature makes them have a great potential to resist subduction and initiate a new subduction zone behind the plateaus, yet the geodynamic process remains enigmatic. Here, we use 2D thermo‐mechanical modeling method to investigate the role of an oceanic plateau in subduction zone reorganization. We systematically examine the rheological strength and compositional density of oceanic plateau mantle and the size of oceanic plateau. Three distinct subduction styles are observed: (a) steep subduction without subduction zone reorganization, favored by a small‐sized (≤150 km) or lowly depleted oceanic plateau; (b) breakoff of subducting slab followed by flat‐slab subduction, which is conditional on a moderate‐sized (≥300 km) oceanic plateau with high degree depletion but relatively low strength; and (c) initiation of a new subduction zone behind the plateau (subduction zone jump), facilitated by a moderate‐sized oceanic plateau with a strongly depleted mantle root. The geodynamic results demonstrate that the overriding lithosphere undergoes a tectonic force switch from compression to tension in ∼5 Myr as the subduction zone is reorganized. This can be reflected in the crustal deformation of the overriding plate and used as an indicator to identify past subduction zone jumps. The spatial relationship pred...