T165 Orogenic Plateaus From Top to Bottom (Posters)
LARAMIDE DEFORMATION OF THE COLORADO PLATEAU AND THE EVOLUTION OF ANCIENT FAULT ARRAYS
Paper number: T165-10
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM
Authors
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George H. DavisUniv of Arizona, Tucson, AZ
Abstract
Using structure contour maps of the Cretaceous Dakota Sandstone, we constructed strike parallel throw profiles for each of these monoclines. Assuming that the underlying faults do not exhibit wild changes in dip along strike, these throw profiles reflect strike-parallel variations in reverse displacement on the underlying basement faults. Individual profiles exhibit varying degrees of sawtooth character but each tapers from a maximum in the middle to a minimum at each end, much like a typical fault. Aggregate throw profiles for the two systems display a similar shape, grading from near a minimum at each end to a maximum in the middle. By analogy with modern fault systems, we suggest that these monoclines are the surface expression of kinematically linked basement faults. Thus, while ancient weaknesses may have provided the initial locus for Laramide deformation, they are not static features. Indeed, these faults appear to have evolved, growing laterally and forming new linkages during the Laramide orogeny.