Whipple Mountains

The Whipple Mountains ('Avii Kur'utat [Munro, P et al. "A Mojave Dictionary" Los Angeles: UCLA, 1992] in Mojave) are located in southeastern California south of Lake Havasu City, Arizona, and north of the Arizona town of Parker. The range stretches approximately convert|25|mi|km in an east-west direction, and reaches an elevation of convert|2695|ft|m at Savahia Peak at the western end. The Whipple Mountains are home to many mines including the Independence Mine and Bessie Mine. The range lies in San Bernardino County in the Colorado Desert, the western extension of the Sonoran Desert.

Geography

The following United States Geological Survey (USGS) 7.5' Quadrangle maps provide coverage of the Whipple Mountains:

*Gene Wash
*Havasu Lake
*Lake Havasu City South
*Parker
*Parker NW
*Savahia Peak
*Whipple Mountains SW
*Whipple Wash

Climate

Data from the Western Regional Climate Center reveals this to be a region of extreme aridity (<150mm/yr), very high summer temperatures (+40 °C) and mild winter temperatures.

Geology

The present-day landform of the Whipple Mountains is a series of sub-parallel ridges trending northwest to southeast, cut at right angles by a large wash which bisects the entire range. These linear ridges mark the tops of tilted crustal blocks lying in the hanging wall of an extensive detachment fault, and the range as a whole comprises one of the best exposed and most studied metamorphic core complexes in the world.

In the western half of the range, the hanging wall has been eroded away completely, leaving antiformally upwarped lower-crustal mylonites exposed at the surface. To the east, unaltered tertiary volcanic and sedimenatary rocks along with non-mylonitic crystalline Pre-Cambrian rock in the hanging wall form the land surface, but the larger washes provide access to the detachment surface and the rocks surrounding it. Excellent examples of hydrothermal alteration, fluidized cataclasite injection, and other mid- and upper-crustal fault processes abound along the detachment surface. A number of high-angle normal faults accommodating tilting and extension within the hanging wall are easily visible as well.

The Whipple detachment fault is part of a larger complex of shallow, east dipping normal faults extending from the Whipples northward to the southern tip of Nevada, where a transition occurs to shallow, westward dipping normal faults. The entire region accommodated major crustal extension between the Sierra Nevada block and the Colorado Plateau during the early and middle Miocene. Upwards of 40 km of extension occurred in a region now 70 to 100 km across.

History

Wyatt Earp spent his last winters here working small gold and copper mining claims starting around 1906. The nearby townsite of Earp, California on and near those claims was named for him, although his residence actually stands in the town of Vidal, California.

Access and Legal Status

The bulk of the Whipple Range lies within the Whipple Mountains Wilderness, administered by the Needles Field office of the United States Bureau of Land Management (BLM). The wilderness covers approximately convert|79861|acre|km2 of the range, and wheeled and motorized vehicles are excluded from the entire wilderness area. Hiking and horseback riding are the primary means of accessing the interior of the range, and the most frequently used route for such activities lies in Whipple Wash which bisects the range from southwest to northeast. Motorized access to the boundary of the wilderness is possible only from the north-east side by way of a powerline access road, accessible to high-clearance, four-wheel-drive vehicles. No permit is required for individual access, but commercial or organized group access must be permitted by the BLM.

Portions of the range within and without the wilderness area are owned by the State of California and private land owners. Access to these areas is determined by these owners and not by the BLM.

External links

* [http://www.ca.blm.gov/needles/whipple.html Bureau of Land Management Needles Field Office -- Whipple Mountains Wilderness Information Page]
* [http://vredenburgh.org/desert_fever/pages/san_bernardino_04.htm Mining History of the Whipple Mountains]

References

*cite book|first=Stuart|last=Allan|title=California Road and Recreation Atlas|year=2005|publisher=Benchmark Maps|pages=p. 115|id=ISBN 0-929591-80-1