Effects of lithospheric in‐plane stress on sedimentary basin stratigraphy

Abstract

In‐plane lithospheric stress, though known to exist, has generally been ignored in the quantitative modeling of basin stratigraphy. However, low levels of intraplate lateral stress can induce observable plate deformations (10–100 m of vertical motion) if the lithosphere contains a preexisting deformation (such as a sedimentary basin). The importance of in‐plane stress in modifying the stratigraphy of a sedimentary basin has been assessed using an elastic plate model for the lithosphere. A compressive in‐plane stress generally induces basin subsidence with peripheral uplift (shoreline regression), while a tensile in‐plane stress induces basin uplift and peripheral subsidence (shoreline transgression). These simple results are complicated by variations in crustal thickness, as now two interfaces are involved, that is, the sediment/basement interface of the sedimentary basin and the Moho topography; the isostatic state of a sedimentary basin therefore ultimately controls the resultant deformation induced by in‐plane stress. The implications of in‐plane stress modification of basin stratigraphy are profound: regionally correlatable transgressions and regressions of basin interiors (e.g. cyclothems) and passive continental margins (the third‐order variations of the Vail et al. [1977a] coastal onlap curve), may be tectonically produced by the interaction of stress‐induced base level changes and a basin tectonic driving subsidence. In‐plane stress, its generation, magnitude, and variation, is considered a consequence of plate boundary reconfigurations during continental collisions, rifting, and subduction/obduction.