Sedimentary loading, lithospheric flexure, and subduction initiation at passive margins

Investigation of lithospheric flexure at continental margins by sedimentary loading has been carried out using elastic-plate theory. The geometry of mature marginal basins fits the deflection produced by loading of an infinite plate in which the flexural rigidity of the continental lithosphere is larger than that of oceanic lithosphere. Decoupling of a previously locked passive margin by reactivation of margin faults may cause the lithospheric bending behavior of the margin to change from that of an infinite plate to that of a semi-infinite plate, with a resultant increase in deflection of the marginal basin and possible subduction initiation.