Paleostress in Cratonic North America: Implications for Deformation of Continental Interiors

摘要

Compressive paleostresses, as recorded by twinned calcite in carbonate rocks that cover cratonic northwestern North America, are perpendicular to the orogenic front of the Late Cretaceous to Early Cenozoic Sevier fold-thrust belt. Inferred differential stresses decrease from ～100 megapascals (MPa) at the orogenic front to ～20 MPa up to 2000 kilometers inland. New analyses near the Late Paleozoic Appalachian 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 tectonic properties. This suggests that continental interior stresses are largely insensitive to tectonic characteristics of compressive plate margins and that far-field stress transmission is filtered by deformation styles in mountain belts.