PALEOSTRESS IN CRATONIC NORTH-AMERICA - IMPLICATIONS FOR DEFORMATION OF CONTINENTAL INTERIORS

Compressive paleostresses, as recorded by twinned calcite in carbonate rocks that cover cratonic northwestern North America, are perpendicul ar to the orogenic front of the Late Cretaceous to Early Cenozoic Sevi er fold-thrust belt. Inferred differential stresses decrease from simi lar to 100 megapascals (MPa) at the orogenic front to similar to 20 MP a up to 2000 kilometers inland. New analyses near the Late Paleozoic A ppalachian front refine earlier results from the eastern Midcontinent. The Appalachian and Sevier stress data in North America's continental interior are remarkably similar in spite of distinctly different tect onic properties. This suggests that continental interior stresses are largely insensitive to tectonic characteristics of compressive plate m argins and that far-field stress transmission is filtered by deformati on styles in mountain belts.