Basin and Range Province

The Basin and Range Province is a very long-range geological province, which includes large parts of the southwestern United States and northwestern Mexico. The determining geomorphologic elements are the Basin and Ranges ( pool and mountain ranges ) that represent a topography of parallel nests and trenches.

Expansion

The province extends from the Colorado Plateau from the west up to the Sierra Nevada and surrounding south northeastern Baja California. It extends to the U.S. side over parts of the states of Arizona, Idaho, California, New Mexico, Oregon, Texas, Utah, and practically all over Nevada ( only a small part of the northern Elko County drains to the Snake River ). On the Mexican side, the states of Baja California, Chihuahua and Sonora likewise show a typical Basin and Range topography.

The longitudinal extent of total 3000 km, the southernmost point in the province is directly north of Mexico City, may have been even more affected Oaxaca. The maximum width expansion reaches 1000 km, but which are reduced to the Latitude of Las Vegas to only 350 km.

The Sierra Madre Occidental shares on the Mexican side the Basin and Range province into two halves.

As a major landscapes are the arid Great Basin, the Chihuahuan Desert and the Sonoran Desert largely to Basin and Range Province.

Geological development

The Horst- grave and topography of the Basin and Range Province is the result of a crustal strain. The Lara mixer orogeny, in the Rocky Mountains formed, was triggered when the Farallon plate from the west dove under the North American plate and thus generated pressure in west-east direction. It ended about 35 million years ago when the Farallon plate was subducted completely down to small fragments in the subduction zone on the west coast of North America. As such, the lateral pressure on the North American Plate accounted arose in the previously compressed rock is stretching. Parallel ridges were also lifted on the North -South trending faults simultaneously slumped grave zones to the same problems. In this way, thus gave rise to the alternating pattern of straight ridge ( ranges ) and basins ( basins ).

As early as 35 million years BP (Upper Eocene, Priabonium ) began first flat-lying faults with the elongation process of tectonically thickened crust and metamorphic core complexes were formed ( bulges of metamorphic lower crust ). The actual crustal strain continued, however, until about 16 million years BP a ( Miocene, Langhium ), elongation direction was east-northeast. From the Upper Miocene ( Tortonian ) to eight million years BP was carried out with a change of direction in a clockwise direction after Eastsoutheast a second phase in the expansion process, and it also changed the tectonic style. Steep standing distortions overprinted the previous structures, and there was the current Horst and grave structure.

The fact is that the crust has extended up to 100 percent in its original width dimension and now beneath the Basin and Range Province is one of the thinnest crust areas worldwide.

Mineral resources

From the Basin and Range Province originate almost sämtliches copper and a large part of the gold, silver and Barytproduktion the United States. In Nevada, even somewhat crude oil is produced.

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