Geologic Timeline of Western North America

A timeline of significant geological events in the evolution of western North America. Dates are approximate. ("Ma" = millions of years ago)

Date Period/Epoch Event
350 Ma Devonian An unnamed terrane collides and accretes to the North American Plate, along a line roughly coinciding with the Nevada–Utah border and called the Carlin Unconformity.
250 Ma Permian The Sonomia Terrane collides and accretes to the North American Plate, along a line called the Golconda Thrust (also the name of the event) which runs through central Nevada.
200 Ma Triassic Sierra Nevada batholith first develops.
180 Ma Jurassic The Intermontane Plate collides with the Pacific Northwest, the remnants of which form the Intermontane Belt today.
165 Ma Jurassic The Smartville Block, an island arc terrane, collides and accretes to the North American Plate, along a line which coincides with the Mother Lode country of California.
140 Ma Jurassic Second wave of plutons added to Sierra batholith.
115 Ma Cretaceous The Insular Plate collides with the Pacific Northwest. The remnants of that terrane comprise the Insular Belt today, of which Vancouver Island is a part.
90 Ma Cretaceous Third and last wave of plutons added to Sierra batholith.
43 Ma Eocene The Pacific Plate changes its direction of motion from north to northwest.
35 Ma Eocene Rio Grande Rift begins to form.
20 Ma Miocene San Andreas Fault comes into being as the North American Plate begins splitting the Farallon Plate in two.
17 Ma - 14 Ma Miocene Columbia River Basalt Group Forms.
8 Ma Miocene Onset of faulting creating the Basin and Range geologic province.
5 Ma Miocene - Pliocene Northward propagation of the East Pacific Rise into the North American Plate initiates rifting off of the Baja California peninsula.
4 Ma Pliocene Sierra Nevada begins to rise.
3.5 Ma Pliocene The Pacific Plate changes its direction of motion about 11 degrees east of its previous heading, from northwest to the present northwest by north.

Famous quotes containing the words north america, western, north and/or america:

    The Anglo-Saxon hive have extirpated Paganism from the greater part of the North American continent; but with it they have likewise extirpated the greater portion of the Red race. Civilization is gradually sweeping from the earth the lingering vestiges of Paganism, and at the same time the shrinking forms of its unhappy worshippers.
    Herman Melville (1819–1891)

    One good reason for the popularity of “reductionism” among the philosophical outposts of the Western Establishment is that it can be, and is, used as a device for trying to take the wind, so to speak, out of the sails of Marxism.... In essence reductionism is a kind of anti-Marxist caricature of Marxist determinism. It is what anti-Marxists pretend that Marxist determinism is.
    Claud Cockburn (1904–1981)

    The North is full of tangled things and texts and aching eyes
    And dead is all the innocence of anger and surprise,
    And Christian killeth Christian in a narrow dusty room,
    And Christian dreadeth Christ that hath a newer face of doom,
    And Christian hateth Mary that God kissed in Galilee,
    Gilbert Keith Chesterton (1874–1936)

    To be black and an intellectual in America is to live in a box.... On the box is a label, not of my own choosing.
    Stephen Carter (b. 1954)