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 146 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. Much like the two orogenies that followed, the Nevadan was caused by the subduction of oceanic lithosphere at a subduction zone running along the edge of the North American continent. The subduction was relatively slow due to a reduced rate of sea floor spreading, this resulted in relatively cool oceanic crust descending into the lithosphere very quickly, and steeply beneath the edge of the continent. As a result, magma rose from the melting oceanic crust producing a chain of volcanoes located close to continent's edge. This volcanic activity over the course of several million years would form what is today the Sierra Nevada Mountains of California. Mountain building is when mountains develop out of previously lower terrain, or even seas. ... World map showing location of North America A satellite composite image of North America North America is the third largest continent in area and fourth in population after Asia and Africa in area and population and Europe in population. ... The Jurassic period is a major unit of the geologic timescale that extends from about 200 million years BP at the end of the Triassic to 146 million years BP at the beginning of the Cretaceous. ... In geology, orogeny is the process of mountain building. ... The Mesozoic is one of three geologic eras of Phanerozoic eon. ... The Cenozoic or Cainozoic era (sometimes Caenozoic Era) is the most recent of the four classic geological eras. ... The Laramide orogeny was a 30 million year period of mountain building in western North America that started in the Late Cretaceous, 70 million years ago, and ended in the Late Paleogene 40 million years ago. ... Subduction zones mark sites of convective downwelling of the Earths lithosphere. ... Categories: Geology stubs | Plate tectonics ... Seafloor spreading is a part of the theory of plate tectonics. ... Oceanic crust is the part of Earths lithosphere which underlies the ocean basins. ... The lithosphere (from the Greek for rocky sphere) is the solid outermost shell of a rocky planet. ... Dymaxion map by Buckminster Fuller shows land mass with minimal distortion as only one continuous continent A continent (Latin continere, to hold together) is a large continuous land mass. ... This article is about the type of molten rock. ... This article is about volcanoes in geology. ... The Sierra Nevada is a mountain range that is mostly in eastern California. ... State nickname: The Golden State Other U.S. States Capital Sacramento Largest city Los Angeles Governor Arnold Schwarzenegger Official languages English Area 410,000 kmÂ² (3rd) - Land 404,298 kmÂ² - Water 20,047 kmÂ² (4. ...
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