abstract:The Nevadan Orogeny was a major mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic (between about 180 and 140 million years ago). The Nevadan orogeny was the first of three major mountain building episodes to transform Western North America between the Late Mesozoic and Early Cenozoic Eras, the latter two being the Sevier and Laramide orogeny, chronologically.