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When did the Laramide Orogeny occur?
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Rocky Mountains
Physical features of western North America.
The Laramide orogeny was not a single event but a series of mountain-building pulses that occurred across western North America over an extended period.
These deformation events took place from the Late Cretaceous Period through the Paleogene Period and lasted as late as the Oligocene Epoch, which ended approximately 23 million years ago. While the orogeny was once thought to be confined to the Cretaceous–Tertiary boundary, it is now understood to be a polyphase process with varying intensity and timing across different regions. Igneous intrusions associated with the orogeny, however, are generally centered around the Cretaceous-Tertiary boundary.1