Skip to Main Content


The Western Interior Cretaceous Basin of North America evolved as a complex foreland basin between Late Jurassic and Cretaceous time in response to accelerated plate spreading, convergence, and subduction along the western margin of North America. Westward translation of compressive forces episodically deformed this basin, and divided it into six discrete structural provinces: (1) A western zone of pluton-ism, volcanism, and thrusting - the Cordilleran thrust belt; (2) a foreland basin which subsided rapidly in response to thrust and synorogenic sediment loading; (3) a discontinuous forebulge zone east of the foreland basin; (4) a broad axial basin characterized by subsidence at rates greater than sedimentation during structurally active periods; (5) a tectonic hinge zone on the east side of the axial basin, at its junction with the North American craton; and (6) a broad eastern stable cratonic zone. This basin was flooded by shallow Cretaceous epicontinental seas from the north and south beginning in Barremian-Aptian time. These discrete arms of the seaway joined in Late Alb-ian, and after a brief latest Albian separation across the Transcontinental Arch, the basin remained flooded for 38 Ma until late Middle Maastrichtian time. Initial flooding of the Western Interior Basin, and dynamic changes in the shape, size, and depth of this epicontinental sea reflected the complex interaction of episodic basin tectonics and first- through fourth-order tectonoeustacy, reflecting plate tectonic (especially seafloor spreading) activity levels. The Western Interior Cretaceous Seaway was highly dynamic throughout its history; its temperature, chemistry, circulation patterns and levels, stratification characteristics, shape and size varied greatly, and episodically in concert with tectonic, eustatic, and climatic factors and their interaction. Consequently, the sedimentologic record of basin evolution in the Western Interior Seaway is complex, and reflects both local, autocyclic and, more predominantly, regional to global allocyclic processes. Eustatic and climatic cycles were the prevailing controls of cyclic sedimentation, which is well defined in the basin center (e.g. Pueblo), and more complex in its marginal basin development. High resolution event-stratigraphy and assemblage zone biostratigraphy provide independent means of correlating diverse aspects of basin evolution, through graphic correlation, into a coherent basin model. This model suggests a two-phase evolution of the basin. Times of active plate spreading, ridge-building, and thus eustatic rise are generally coeval with active plutonism, volcanism, thrusting, and rapid subsidence in the Western Interior Basin of North America, preserving thick transgres-sive sediment sequences. Times of plate quiescence are also times of tectonic quiescence and filling of the basin associated with eustatic fall and regression.

You do not currently have access to this chapter.

Figures & Tables





Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal