Maria fold and thrust belt

Maria Fold-and-Thrust-Belt
Ranges, Plains & Thrusted Forms
Country	United States
States	California, Arizona
Regions	Mojave Desert-NW—Sonoran Desert-SE
Counties	San Bernardino County-CA Mohave County-AZ-(N) La Paz County-AZ-(S)
Municipalities	Lake Havasu City—Parker-AZ Vidal Junction—Blythe-CA Quartzsite-AZ

Borders on	Mojave Desert-Colorado Desert-W Mojave Desert-AZ-(north) Sonoran Desert-AZ-(east)
Lake	Lake Havasu
River	Chemehuevi Wash-CA-(n-west perimeter) Colorado River-(N-S) Bill Williams River-(E-W, (tributary))

Length	65 mi (105 km), NW-SE
Width	45 mi (72 km)

The Maria fold and thrust belt (MFTB) is a portion of the North American Cordillera orogen in which geological structures accommodate roughly north-south to northwest-southeast vergent Mesozoic age crustal shortening. This lies in contrast to the remainder of the Cordillera, in which shortening is predominantly East-West. Structures associated with the Maria Fold and Thrust Belt are exposed in a series of mountain ranges in southeastern California and western Arizona.^[1] Many of the deep structures of the MFTB have been exposed due to east-west to northeast-southwest Cenozoic age extension and unroofing.

In some parts of this fold-and-thrust-belt region, the extension resulted in the emplacement of metamorphic core complexes, the 'type example' of which is defined by the Whipple Mountains in southeastern California.

Geology

The Maria fold-and-thrust-belt is defined as the region where the compression that helped create the North American Cordillera – abruptly changed directions. North of the Maria fold-and-thrust-belt, the mountain ranges trend north-south, with east-west compression due to the subduction of the Farallon slab beneath western North America. At the Maria fold-and-thrust-belt, compressional deformation shifts to being generally north-south, with the front of the mountain ranges being defined by a roughly east-west line. This line then shifts gently to the east-southeast, where the Cordilleran deformation diffuses into a broad shear zone in northeastern Mexico.

Another notable feature that differentiates it from the rest of the Cordillera is that the deformation involves the rocks of the North American craton. Deformation in the remainder of the Cordillera only involves rocks that were part of the near-shore and offshore, sedimentary sequences.

Ecology

Since soils and climate differ across the Maria fold-and-thrust-belt, this regional geologic structure can be considered a "dividing line" for a number of flora and fauna species. For example, the species range of the endangered California Fan Palm, Washingtonia filifera does not extend north of the Maria fold-and-thrust-belt, or more specifically the Turtle Mountains.^[2]

Ranges

The Maria fold-and-thrust-belt comprises a large number of ranges in the south-eastern Mojave and north-western Sonoran deserts,^[3] including the:

Regional landforms

List of some regional landforms. (The ~east-west Bill Williams River appears as part of the central and northern perimeter of the Maria fold-and-thrust-belt, approximately paralleling the Rawhide Mountains, a slight northwest range on west end.)

Lower Colorado River Valley
McMullen Valley
Ranegras Plain
Rice Valley
Vidal Valley

References

↑ Knapp, J. H.; Heizler, M. T. (1990). "Thermal History of Crystalline Nappes of the Maria Fold and Thrust Belt, West Central Arizona". Journal of Geophysical Research. American Geophysical Union. 95 (B12): 20,049–20,073. doi:10.1029/jb095ib12p20049.
↑ C. Michael Hogan. 2009. California Fan Palm: Washingtonia filifera, GlobalTwitcher.com, ed. Nicklas Stromberg
↑ Spencer, Jon; Reynolds, S. J. (1990). "Relationship between Mesozoic and Cenozoic tectonic features in west-central Arizona and adjacent southeastern California". Journal of Geophysical Research. 95 (B1): 539–555. Bibcode:1990JGR....95..539S. doi:10.1029/JB095iB01p00539.

Wikimedia Commons has media related to Maria fold and thrust belt.

External links

Maria Fold and Thrust Belt, University of Colorado Western US Tectonics Course

Seismically active fault zones and tectonic blocks of California

Statewide Faults	San Andreas Fault

Faults, zones, and blocks of Southern California	Brawley Seismic Zone Chino Fault Elsinore Fault Zone Elysian Park Fault Garlock Fault Hosgri Fault Imperial Fault Zone Laguna Salada Fault Newport–Inglewood Fault Peninsular Ranges Puente Hills Fault Raymond Fault Rose Canyon Fault Salton Trough Salinian Block San Cayetano Fault San Felipe Fault Zone San Gabriel Fault San Jacinto Fault Zone Santa Maria River Fault Santa Ynez Fault Shoreline Fault Ventura Fault White Wolf Fault Whittier Fault Yorba Linda Fault

Faults and zones of Northern California	Bartlett Springs Fault Calaveras Fault Clayton-Marsh Creek-Greenville Fault Concord Fault Hayward Fault Zone Healdsburg Fault Maacama Fault Mendocino Fracture Zone Mendocino Triple Junction Mount Diablo Thrust Fault Monta Vista Fault Pleasanton Fault San Gregorio Fault San Pablo Fault Seal Cove Fault Serra Fault Silver Creek Fault Tesla Fault West Napa Fault

Sierra Nevada faults, zones, and blocks	Death Valley Fault Zone Furnace Creek Fault Zone Honey Lake Fault Zone Kern Canyon Fault Maria fold and thrust belt Owens Valley Fault Rescue Lineament-Bear Mountains fault zone Sierra Nevada Batholith Sierra Nevada Fault Sierra Nevada-Great Valley Block Smartville Block Walker Lane

Category California Geological Survey Seismic Hazards Mapping Act Mexico (list)

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