Geology of North America

The geology of North America, like most topics of scientific study, is undergoing progressive investigation by numerous public- and private-sector earth scientists, academicians, and students. In that regard, the detailed picture is subject to revision and change as knowledge advances.

Geologic provinces

The lower 48 U.S. states can be divided into roughly five physiographic provinces:
# The American cordillera.
# The Canadian Shield.
# The stable platform.
# The coastal plain.
# The Appalachian orogenic belt.

The geology of Alaska is typical of that of the cordillera, while the major islands of Hawaii consist of Neogene volcanics erupted over a hot spot.
[
Utah.] The American cordillera extends roughly from the Great Plains westward to the Pacific Ocean, narrowing somewhat from north to south. It includes the Cascades, Sierra Nevada, and Basin and Range province; the Rocky Mountains are sometimes excluded from the cordillera proper, in spite of their tectonic history. The geology of this region is complex, having gone through numerous orogenies, with their associated deformation, faulting, volcanic activity, and periods of uplift separated by intervals of erosion. Much of the cordillera consists of terranes, ancient microcontinents and island arcs that were "welded" onto the North American craton during the Paleozoic and Mesozoic eras. Such a convoluted history is typical of convergent plate boundaries, as has characterized the cordillera through most of the Phanerozoic. Although the Colorado Plateau is near the cordillera, it has remained tectonically stable, with little deformation.

The Canadian Shield consists of surficial, deeply eroded Precambrian rocks, exhumed by past glaciations. Consisting of a variety of rocks from igneous to ancient sedimentary, it is well-exposed only in the Great Lakes region.

A large part of the center of the lower 48 consists of the stable (or continental) platform. Here, the Precambrian rocks of the Shield are buried beneath sedimentary Phanerozoic strata. Tectonic activity is minor to nonexistent, with occasional broad domes and basins that reveal mild epeirogenic deformation. The coastal plain extends from the southern tip of Texas across the northern Gulf of Mexico and into the Mississippi embayment, and northeast through the Mid-Atlantic states. A classic passive continental margin, it consists of a deep clastic wedge of sediment eroded from the platform and mountain belts; it first formed during the opening of the Atlantic Ocean and Gulf of Mexico during the Jurassic and Cretaceous periods.

The Appalachian orogenic belt extends from well into New England south into Mississippi and Alabama. The Ouachita Mountains of Arkansas, and even the Marathon uplift of Texas are also part of the same province, having all formed in the Alleghenian orogeny that took place when Pangea assembled during the late Paleozoic. Once lofty, they have been heavily weathered since the opening of the Atlantic Ocean. The Appalachians proper consist of deformed sedimentary rocks, cut through by numerous thrust faults; as in the western cordillera, the Appalachians experienced several orogenies over the course of the Paleozoic, making their geologic history difficult to interpret.

Geology of the Rocky Mountains

*Burgess Shale
*Cloverly Formation
*Columbia Icefield
*Dakota Hogback
*Dakota Sandstone
*Denver Basin
*Geology of the Grand Teton area
*Gold mining in Colorado
*Grand Mesa
*Great Divide Basin
*Green River Formation
*La Garita Caldera
*Lance Formation
*Laramide orogeny
*Morrison Formation
*Pikes Peak granite
*Powder River Basin
*Raton Basin
*Rocky Mountain Association of Geologists
*Rocky Mountain Trench
*Silver mining in Colorado
*Sundance Sea
*Triple Divide Peak
*Uranium mining in Colorado
*Uranium mining in Wyoming
*Western Interior Seaway

eismic faults

*Basin and Range Province
*Clarendon-Linden fault system
*Humboldt fault
*Moab Fault
*New Madrid Seismic Zone
*Seattle Fault
*Wasatch Fault

Faults in California

*Calaveras Fault
*Clayton-Marsh Creek-Greenville Fault
*Elsinore Fault Zone
*Garlock Fault
*Hayward Fault Zone
*Healdsburg Fault
*Mendocino Fracture Zone
*Monta Vista Fault
*Newport-Inglewood Fault
*Raymond Fault
*San Andreas Fault
*San Gabriel Fault
*Sierra Nevada Fault
*Silver Creek Fault
*Tesla Fault
*White Wolf Fault
*Whittier Fault

Mines

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Geology of U.S. states

*Geology of Alabama
*Geology of Connecticut
*Geology of Delaware
*Geology of Georgia
*Geology of Idaho
*Geology of Illinois
*Geology of Iowa
*Geology of Kansas
*Geology of Minnesota
*Geology of New Jersey
*Geology of Oklahoma
*Geology of Pennsylvania
*Geology of Tennessee
*Geology of Texas
*Geology of West Virginia

Related images

ee also

*Geology of the Pacific Northwest
*Geology of the Yosemite area
*Absaroka sequence
*Acadian orogeny
*Anadarko Basin
*Chazy Formation
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*Fort Payne Formation
*Geological Exploration of the Fortieth Parallel
*Geology of the Appalachians
*Geothermal features of Yellowstone
*Hawaiian Islands
*Ice Age National Scientific Reserve
*Laurentide ice sheet
*Kaskaskia sequence
*Laramide orogeny
*Meramec (series)
*Mountain peaks of North America
*Queenston Delta
*Ridge-and-valley Appalachians
*Sauk sequence
*Sevier orogeny
*St. Louis Limestone
*Ste. Genevieve Limestone
*Taconic orogeny
*Tejas sequence
*Tippecanoe sequence
*Western Interior Seaway
*Zuñi sequence

References

*Marshak, Stephen. (2001) "Earth: Portrait of a Planet", New York: W.W. Norton & Company, ISBN 0-393-97423-5. pp. 339-44, 401-2.

External links

* [http://geology.about.com/od/usageologicmaps/ Geologic Maps of the U.S. from About.com]
* [http://tapestry.usgs.gov/Default.html A Tapestry of Time and Terrain: The Union of Two Maps - Geology and Topography (USGS)]