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| Joshua Tree National Park is located in southern California on the eastern
end of the broad mountainous belt called the Transverse Ranges, which stretch
from Point Arguello, 50 miles west of Santa Barbara, eastward for nearly
300 miles to the Eagle Mountains in the Mojave Desert. Unlike most mountain
ranges in North America that run north-south, the Transverse Ranges lie
on an east-west axis. |
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| Within the park there are six distinct mountain ranges: the Little San
Bernardino Mountains in the southwestern part; the Cottonwood, Hexie, and
Pinto Mountains in the center; and the Eagle and Coxcomb Mountains in the
eastern part. Both the southern and northern margins of the park are marked
by steep escarpments that rise abruptly from the lower desert areas. Much
of the park lies at elevations above 4,000 feet. |
| Between the park’s numerous mountain ranges, there are valleys, which
are classified according to their method of formation. Queen Valley and
Lost Horse Valley were formed by a difference in the rate of erosion between
the rock underlying the valley itself and the rock composing the surrounding
mountains. The mountainous rock is more resistant to erosion and therefore
rises above the valleys. Pleasant Valley, on the other hand, was formed
by down-dropped motion along faults that formed basins (called grabens).
Some valleys have playas: lakes that may contain water a few weeks a year
during the rainy season. |
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http://www.nps.gov/jotr/nature/geology/formations.html
last modified: 03/27/02
web editor: Sandra kaye |
