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地球物理学报 2009
The numerical modeling of the formation and evolution of rifted continental margin
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Abstract:
On the basis of the isoviscous corner flow model, we established upwelling divergent mantle flow field. When this flow field acts on the base of continental lithosphere, the deformation and thinning of continental lithosphere leading to breakup and the initiation of sea-floor spreading can be described. The numerical modeling results indicate that lithosphere behaves as depth-dependent stretching manifested as stretching factors from different depth are different, and the surface heat significantly increases in response to an upwelling divergent mantle flow. The isostatic adjustment due to the mantle flow-induced thermal disturbance leads to surface subsidence; meanwhile, the thermal disturbance reduces the rheological strength of lithosphere, especially at deformation center. The critical depth of brittle deformation is reduced and the range of ductile deformation becomes larger significantly. This deformation finally evolves into continental breakup, mantle exhumation, and the formation of sea-floor spreading and rifted continental margin under the continuing impact of upwelling divergent mantle flow.