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:

    “New York is a meeting place for every race in the world, but the Chinese, Armenians, Russians, and Germans remain foreigners. So does everyone except the blacks. There is no doubt but that the blacks exercise great influence in North America, and, no matter what anyone says, they are the most delicate, spiritual element in that world.”
    —Federico García Lorca (1898–1936)

    “Westron wind, when will thou blow?
    The small rain down can rain.
    Christ, that my love were in my arms,
    And I in my bed again.”
    —Unknown. Western Wind (l. 1–4)

    “The North has no interest in the particular Negro, but talks of justice for the whole. The South has not interest, and pretends none, in the mass of Negroes but is very much concerned about the individual.”
    —Zora Neale Hurston (1891–1960)

    “Oh, it’s home again, and home again, America for me!
    I want a ship that’s westward bound to plow the rolling sea,
    To the blessed Land of Room Enough beyond the ocean bars,
    Where the air is full of sunlight and the flag is full of stars.”
    —Henry Van Dyke (1852–1933)