San Benito Mountain
Encyclopedia
San Benito Mountain is a mountain located in the Diablo Range
of California
. The mountain, which rises to an elevation of 5267 feet (1,605 m), is the highest point in San Benito County
and the Diablo Range
and is also the highest point in the San Francisco Bay Area
, though due to distance from other cities and the inner core of the region, Mount Hamilton
is considered the region's highest point. The mountain gets some snowfall during winter.
The Clear Creek Management Area, which encompasses the San Benito Mountain Research Natural Area, has been subject to a temporary closure by the BLM since May 2008 due to concerns of visitor exposure to naturally occurring asbestos
(chrysotile). The area was a major OHV riding area prior to the closure. The core area of the Clear Creek Management Area (approximately 35,000 acres) is the New Idria serpentine mass. The serpentine is highly sheared/pulverized and contains abundant chrysotile asbestos.
Extreme shearing of the bedrock, combined with soil nutrient imbalances, has resulted in extensive areas of natural barrens completely devoid of vegetation. The serpentine soils harbor several rare plant species, including the Federally listed Threatened San Benito evening primrose (Camissonia benitensis). A unique pine and incense cedar forest occurs at the highest elevations of the mountain.
The serpentine mass contains two superfund
sites, Atlas Mine and Johns-Mansville. Both were associated with the mining and processing of chrysotile asbestos. Other minerals mined from the serpentine mass included cinnabar, chromite, magnesite, and jadeite. The Gem mine (private) located within the serpentine mass is the only source of gem-grade benitoite in the world. The rare minerals neptunite and joaquinite have also been found there.
Diablo Range
The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges. It is located in the eastern San Francisco Bay area south to the Salinas Valley area of northern California, the United States.-Geography:...
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The mountain, which rises to an elevation of 5267 feet (1,605 m), is the highest point in San Benito County
San Benito County, California
San Benito County is a county located in the Coast Range Mountains of the U.S. state of California, south of San Jose. As of 2010 the population was 55,269. The county seat is Hollister, which includes nearly two-thirds of the county's population. El Camino Real passes through the county and...
and the Diablo Range
Diablo Range
The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges. It is located in the eastern San Francisco Bay area south to the Salinas Valley area of northern California, the United States.-Geography:...
and is also the highest point in the San Francisco Bay Area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
, though due to distance from other cities and the inner core of the region, Mount Hamilton
Mount Hamilton (California)
Mount Hamilton is a mountain in California's Diablo Range, in Santa Clara County, California. Mount Hamilton, at is the tallest mountain overlooking Silicon Valley, and is the site of Lick Observatory, the first permanently occupied mountain-top observatory. The various summits along its...
is considered the region's highest point. The mountain gets some snowfall during winter.
The Clear Creek Management Area, which encompasses the San Benito Mountain Research Natural Area, has been subject to a temporary closure by the BLM since May 2008 due to concerns of visitor exposure to naturally occurring asbestos
Chrysotile
Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in place in the United States and a similar proportion in other countries. It is a soft, fibrous silicate mineral in the serpentine group of phyllosilicates; as such, it...
(chrysotile). The area was a major OHV riding area prior to the closure. The core area of the Clear Creek Management Area (approximately 35,000 acres) is the New Idria serpentine mass. The serpentine is highly sheared/pulverized and contains abundant chrysotile asbestos.
Extreme shearing of the bedrock, combined with soil nutrient imbalances, has resulted in extensive areas of natural barrens completely devoid of vegetation. The serpentine soils harbor several rare plant species, including the Federally listed Threatened San Benito evening primrose (Camissonia benitensis). A unique pine and incense cedar forest occurs at the highest elevations of the mountain.
The serpentine mass contains two superfund
Superfund
Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 , a United States federal law designed to clean up sites contaminated with hazardous substances...
sites, Atlas Mine and Johns-Mansville. Both were associated with the mining and processing of chrysotile asbestos. Other minerals mined from the serpentine mass included cinnabar, chromite, magnesite, and jadeite. The Gem mine (private) located within the serpentine mass is the only source of gem-grade benitoite in the world. The rare minerals neptunite and joaquinite have also been found there.