Transverse ranges
The Transverse Ranges (or more precisely the Los Angeles Ranges ) are a mountain range in Southern California . They begin at the southern end of the California Coast Ranges and lie between the counties of Santa Barbara and San Diego .
The name Transverse Ranges (German "transverse mountain ranges") is derived from their east-west orientation. The Transverse Ranges are perpendicular to the north-south orientation common to most mountain ranges on the California coast and connect the southern California coastal mountains with the Sierra Nevada .
geology
The Transverse Ranges can be divided into two geologically different parts. The western mountains are lower and are mostly made up of sediments and volcanic rocks. The peaks of the eastern Transverse Ranges, on the other hand, reach heights of over 3000 m and consist mostly of Mesozoic granites and Proterozoic metamorphites. The Transverse Ranges are on the North American Plate . The piece of crust broke off the continent at the height of today's northwestern Mexico and rotated clockwise. Thus the mountain range is a result of the tectonic forces between the Pacific Plate and the North American Plate along the San Andreas Fault System. Their orientation along the east-west axis is in contrast to the normal south-east-northwest trend of most large geomorphological structures in California and results from a pronounced curvature in the course of the San Andreas Fault - called Big Bend . The Big Bend was created on the one hand by the expansion of the crust in the Basin and Range Province and on the other hand the American-Pacific plate boundary shifted to the east into the Gulf of California about 6.1 Ma ago .
The Transverse Ranges are different physiogeographical sub-areas of the larger Pacific Border Province , which in turn is part of the larger Pacific Mountain System . They show extreme differences in geological age and composition, varying from sedimentary rocks in the western Santa Ynez and Santa Monica Mountains to primarily granite and metamorphic rocks in the eastern regions, which terminate abruptly in the San Gabriel and San Bernardino Mountains .
geography
The Transverse Ranges begin at Point Conception in Santa Barbara County and include the Santa Ynez Mountains , which run parallel to the coastal mountains beyond Santa Barbara . In Santa Barbara County they also include the San Rafael Mountains and the Sierra Madre Mountains , both of which extend roughly on the border of Ventura County. The Transverse Ranges also include the Topatopa Mountains and the Santa Susana Mountains in Ventura County, and in Los Angeles County the Simi Hills , the Santa Monica Mountains , which run along the Pacific coast behind Malibu and whose eastern part is known as the Hollywood Hills , the steep San Gabriel Mountains northeast of Los Angeles, the Puente Hills and Chino Hills and the San Bernardino Mountains . To the north of the Transverse Ranges are the Central Coast Ranges, Central Valley, and Tehachapi Mountains , which separate the Central Valley from the Mojave Desert to the east and connect the Transverse Ranges to the Sierra Nevada . The Mojave Desert and California's Arid Desert are also part of the Transverse Ranges ; San Miguel Island , Santa Rosa Island , Santa Cruz Island, and Anacapa Island are a western stretch of the Santa Monica Mountains.
Notable mountains in the Transverse Ranges:
- Mount San Gorgonio (3505 m ) in the San Bernardino Mountains
- San Bernardino Peak (3246 m) also in the San Bernardino Mountains
- Mount San Antonio (Old Baldy; 3068 m) in the San Gabriel Mountains
- Mount Wilson (1742 m) in the San Gabriel Mountains
- Mount Pinos (2692 m) in the San Emigdio Mountains
- Frazier Mountain (2446 m) also in the San Emigdio Mountains
- Reyes Peak (2289 m) in Pine Mountain
traffic
There are a number of highways that cross the Transverse Ranges , such as (west to east) Interstate 5 over Tejon Pass , California State Road 14 over Soledad Pass, and Interstate 15 over Cajon Pass . These highways connect southern California with places in the north and northeast such as San Francisco and Las Vegas, respectively . With the exception of higher passes on the lightly traveled California State Routes California State Route 33 , California State Route 2 , California State Route 330 , California State Route 18, and California State Route 38 , none of these passes are high with the Cajon Pass at a modest 1277 m above sea level ; this means that snow is less of a factor here than on the high mountain passes in the north such as Donner Pass . Sometimes heavy snowfall can lead to traffic chaos on the Tejon and Cajon passes. Interstate 5 and Interstate 15 together experience heavy traffic over the mountainous route over these mountains.
ecology
The native plant communities of the Transverse Ranges include coastal sage scrub , chaparral (lower chaparral, upper chaparral and desert chaparral), oak forests and savannas , pinyon-pine-juniper forest, yellow pine forest , coastal pine forest and subalpine forest at higher elevations. The Angeles and Los Padres National Forests cover parts of the Transverse Ranges . The mountain ranges are part of the Californian chaparral and woodland - ecoregion touch, but the eastern end of the mountain range to two deserts ecoregions, the Mojave Desert and the Sonoran Desert . The Carrizo Plain abuts the northern end of the Transverse Ranges .
Chaparral is a common characteristic of the Transverse Ranges . Common plants unite in the chaparral, especially in the transition between coastal chaparral and coastal sage bushes ( California mugwort and heteromeles ; the latter shrub has the Transverse Ranges as its southern limit of distribution ).
Urban influence
A number of densely populated coastal plains and inner valleys lie between the mountain ranges. They include the Oxnard Plain in the coastal area of Ventura County , the Santa Clarita Valley north of Los Angeles and the San Fernando Valley , which consists mainly of the city of Los Angeles. The Los Angeles Basin, which includes parts of Los Angeles County south of the Santa Monica Mountains and most of Orange County , and the Inland Empire Basin, which includes the cities of San Bernardino and Riverside , is located between the Transverse Ranges and the Peninsular Ranges in South.
literature
Patrick Stäheli: California I - South and East; Basin and Range, Transverse and Peninsular Ranges, Death Valley, Mojave Desert, Geology and Excursions. Schweizerbart science publishers, Stuttgart 2013, ISBN 978-3-443-15096-9 .
Web links
- David Hadley, Hiroo Kanamori: Seismic structure of the Transverse Ranges, California. 1977. (PDF; 890 kB, English)