Laramide orogeny

The Laramide orogeny was a mountain-building episode in western North America, chiefly from the Late Cretaceous to Paleogene, that uplifted the Rocky Mountains far inland from the plate boundary.

Shallow-angle subduction: Subduction in which an oceanic plate descends at a low angle beneath an overriding plate. A flattened Farallon slab is the leading explanation for deformation far east of the plate boundary.
North American Plate: A tectonic plate containing most of North America and parts of the Atlantic and Arctic ocean floors. The orogeny deformed its western interior as oceanic lithosphere converged along its margin.
North American Cordillera: The long mountain belt along western North America, formed through successive episodes of subduction, accretion, and deformation. The Laramide episode was one phase in this much longer construction of the continental margin.
Front Range: A mountain range along the eastern edge of the southern Rocky Mountains in Colorado. Its steep eastern margin and uplifted basement exemplify Laramide range structure.
Rocky Mountain foreland basins: Sediment-filled basins formed beside or between uplifted Rocky Mountain ranges. Laramide uplift created adjacent depressions that accumulated thick, locally sourced sediment.
Farallon Plate: An oceanic tectonic plate that subducted beneath western North America before being largely consumed. Its subduction beneath North America supplied the changing forces associated with Laramide deformation.
Rocky Mountains: A major mountain system extending through western North America from Canada to the southwestern United States. Their Laramide ranges include many of the high-standing uplifts produced by the episode.
Farallon Plate subduction: The descent of the Farallon oceanic plate beneath western North America during the Mesozoic and Cenozoic. Changes in its geometry and motion are central to explanations of Laramide onset and inland reach.
Bighorn Mountains: A mountain range in northern Wyoming and southern Montana, bordered by deep sedimentary basins. Their uplift illustrates the isolated basement-cored ranges characteristic of the Laramide province.
Laramide sediments: Sedimentary deposits produced by erosion of Laramide uplifts and preserved in neighboring basins. Their composition and age record the unroofing and growth of the rising ranges.

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