Finite element models of passive continental margins with implications for the initiation of subduction zones.

To investigate the evolution of passive margins, we have constructed finite element models, in which we have incorporated a complex system of forces, depth-dependent rheological properties and lateral variations across the margin. Sediment loading generates differential stresses of several kilobars and dominates the state of stress at passive margins. Such stresses may cause failure of the lithosphere and initiation of subduction. Aging of passive margins alone does not make them more susceptible to initiation of subduction. Extensive sediment loading on young lithosphre might be an effective mechanism for closure of small oceanic basins; it plays an important role in the process of mountain building.-from Authors