A new multilayered model for intraplate stress-induced differential subsidence of faulted lithosphere, applied to rifted basins

In-plane horizontal stresses acting on predeformed lithosphere induce diffe rential flexural vertical motions. A high-precision record of these motions can be found in the sedimentary record of rifted basins. Originally, it wa s proposed that rifted basins experience flank uplift and basin center subs idence in response to a compressive change of inplane stress, which agrees well with observed differential motions. Subsequently published models pred icted that the vertical motions may be opposite because of the flexural sta te of the lithosphere induced by necking during extension. However, the tot al, flexural and permanent, geometry of the lithosphere underlying the rift ed basin is the controlling parameter for the in-plane stress-caused vertic al motions. The largest part of this preexisting geometry is caused by faul ting in the uppermost brittle part of the crust and ductile deformation in the underlying parts of the lithosphere. We present a new multilayered mode l for stress-induced differential subsidence, taking into account the tecto nically induced preexisting geometry of the lithosphere, including faults i n the upper crust. As continental lithosphere may exhibit flexural decoupli ng due to a weak lower crustal layer, the new multilayer in-plane stress mo del discriminates the geometries of the separate competent layers. At a bas in-wide scale, the new model predicts that a compressive change of in-plane force results in basin center subsidence and flank uplift, confirming the original hypothesis. Compared to all previous models, the new model require s a lower horizontal stress level change to explain observed differential v ertical motions.