Basement Control on Laramide Deformation in the Powder River and Williston Basins and Adjacent Areas of the Northern Midcontinent—Tectonic Hierarchy in Continental Lithosphere

Continental lithosphere is subdivided into a tectonic hierarchy in the Powder River and Williston Basins and in adjacent areas of the northern midcontinent of North America. Small units less than about 50 sq mi (130 sq km) are termed “basement blocks”; larger elements of approximately 1000 to 1500 sq mi (18,000 sq km) are designated “lithosphere blocks.” At each scale in the hierarchy, elements consist of a mosaic of smaller units. This tectonic hierarchy in continental lithosphere controlled Laramide deformation as well as earlier episodes of epeirogenic activity.