Abstract:

3D flexural numerical modeling of foreland basins provides a strong supportive tool to help predict 3D basin configuration and distribution of key structural elements, such as forebulges, which are very difficult to recognize  the subsurface due to its low amplitude and wide extent. To explain the forebulge migration observed from detailed stratigraphic correlation, 3D flexural modeling was applied for the Late Cretaceous foreland basin across the Southwestern Wyoming. An elastic lithosphere model was assumed, and detailed chronostratigraphy was used as fundamental framework input in the modeling. Flexural load was estimated from published cross sections across the Wyoming thrust belt and shortening rate of the Wind River thrust. Modeling results indicate that the forebulges were limited in their extent to only the southern part of the basin due to the distribution of the thrust loads. The forebulge shifted southeastward over time due to migration of this load. Because of the interaction of the Wyoming thrust belt and the Wind River Range, the elastic lithosphere formed a 3D “foredome” rather than a 2D “forebulge”. 3D flexural modeling is critical to the understanding of the Late Cretaceous forebulge migration across the Southwestern Wyoming.

Key words: flexural numerical modeling, foreland basins, Upper Cretaceous, Wyoming
CLC number：P5444;P53453Document code：AArticle ID：10052321(2010)04012812