Orogeny and stratigraphy: Numerical models of the Paleozoic in the eastern interior of North America

Publisher Website
Google Scholar
Abstract
A computer model is used to estimate patterns of lithospheric deformation caused by obduction and removal of loads within orogenic belts. Regions of lithospheric downwarp become sedimentary depocenters and regions of lithospheric upwarp suffer erosion. By following the deposition and erosion of sedimentary packages through a number of model time steps it is possible to calculate a synthetic stratigraphy for a given study area. This model is applied to the post‐Early Ordovician stratigraphy of the Eastern Interior region of North America. The loading that drives lithospheric deformation is associated with the development of the Appalachian and Ouachita orogens and the independent development of the Michigan and Illinois intracratonic basins. Model results are shown to be consistent with presently observed stratigraphy, lithology, and cumulative erosion and are then used to estimate the configuration of given sediment packages at discrete intervals following their deposition. These estimates are presented in the form of isopach maps, stratigraphic cross sections, and time‐stratigraphic diagrams as a function of time over the last 470 Ma. By tracking the burial and erosion history of sedimentary units we are able to establish a cause and effect relationship between particular tectonic events and the extent of preservation of sedimentary units. In particular, we suggest that the Pennsylvanian–Permian Alleghanian orogeny produced major sediment cover over much of the study area.