Accretion of oceanic plateaus at continental margins: Numerical modeling |
| |
| Institution: | 1. Département de Géologie et Génie Géologique, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada;2. Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China;3. Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China;4. Fujian Institute of Geological Survey, Fuzhou 350013, China |
| |
| Abstract: | The accretion of oceanic plateaus has played a significant role in continental growth during Earth's history, which is evidenced by the presence of oceanic island basalts (OIB) and plume-type ophiolites in many modern orogens. However, oceanic plateaus can also be subducted into the deeper mantle, as revealed by seismic tomography. The controlling factors of accretion versus subduction of oceanic plateaus remain unclear. Here, we investigate the dynamics of oceanic plateau accretion at active continental margins using a thermo-mechanical numerical model. Three major factors for the accretion of oceanic plateaus are studied: (1) a thinned continental margin of the overriding plate, (2) “weak” layers in the oceanic lithosphere, and (3) a young oceanic plateau. For a large oceanic plateau, the modes of oceanic plateau accretion can be classified into one-sided and two-sided subduction–collisional regimes, which mainly depend on the geometry of the continental margin (normal or thinned). For smaller-sized seamounts, accretion occurs only if all three factors are satisfied, of which a thinned continental margin is the most critical. Possible geological analogues for the two-sided subduction–collisional mode include the Taiwan orogenic belt and subduction of the Ontong Java Plateau. The accretion model for small oceanic plateaus applies to the Nadanhada Terrane in Northeast China. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
