Cargo Muchacho Mountains

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The Cargo Muchacho Mountains taken from space, right above the Algodones Dunes

The Cargo Muchacho Mountains are an American rock group in the extreme southeast California. They are located in Imperial County and form part of the southeastern Colorado Desert near the lower reaches of the Colorado River and the borders of Arizona and Mexico. They reach a height of 676 meters above sea level. Compared to the Salton Sea located below sea level so there is a maximum vertical drop of over 700 meters.

Geography

The mountain range (English range) of the Cargo Muchacho Mountains extends approximately 14 km in a northwest-southeast direction, roughly parallel to the southern section of the west passing San Andreas Fault (or Sand Hills Algodones Fault ), which from here dune field of the Algodones dunes is hidden. Their width is about 7 kilometers. In the northeast and east, it is bordered by the Imperial Valley and the Colorado River. The cities of Yuma and Winterhaven lie to the southeast. In the north and north-west of the Chocolate Mountains close to. In the south of the chain of the All American Canal runs.

Geology

The geological events were described in detail in 1975 by John T. Dillon.

The Cargo Muchacho Mountains basement of the amphibolite facies consists of metamorphic rocks that have been penetrated by synkinematisch mesozonalen granitoids. The granitoids are mainly composed of Adamelliten, but can cover the spectrum gabbro to tonalite. The both the metamorphic rocks and the granitoids distinguishing foliation falls relatively flat one to the south, in her lying stretch Linear pointing in the same direction. The metamorphic rocks - small - to medium -grained quartz-feldspar Tektonite - are primarily associated with the Tumco lineup. Due to lack of stratification can not be clearly defined its origin; perhaps there are former arkoses, but they could be just as emerged from granitoids.

In several places, the basement is unconformably overlain by hardly solidified Fanglomeraten and breccias. The sediments have a tilted angle of incidence of 10 ° and a little more; they in turn were concordant covered by olivine basalts and were thus obtained. The fanglomerates lead alongside locally occurring rock fragments of the basement and exotic volcanic rocks. However, the breccias are derived exclusively from autochthonous rocks from which arose during the tectonically induced fragmentation of the Cargo Muchacho Mountains. This fragmentation is due to several northwest-southeast trending, rechtsverschiebende, steeply dipping faults, which may have a displacement amount of up to two kilometers.

For a jungproterozoisches metamorphic age is assumed. The granitoids are older than 62 million years, according to Armstrong and Suppe ( 1973) and are therefore likely to originate from the Mesozoic era. The basalts were promoted in the Neogene, they can be assigned to the period 23 bis 8 million years

Mineral resources

In the hills was ( and is ) gold mined as placer deposits, for example in the American Girl Mine, the Golden Bee Mine, Mine, and the cargo in the Tumco mine.