Pinnacles National Monument

Pinnacles National Monument is one of the post-prototype parks in the NPS Western Region selected for mapping. Pinnacles National Monument includes parts of Monterey and San Benito Counties. It has a total area of 27,095 acres. The survey area straddles the county line between Monterey and San Benito Counties about 23 miles southeast of Salinas, California.
Elevation ranges from 824 to 3,304 feet It is a rugged to rolling mountain environment with many canyons and several stream valleys with varied geology from volcanic (including ash, breccia, rhyolite) to granitic and alluvial surfaces.

National monuments are among the most sensitive and protected natural areas in America. The Access Fund, Friends Of Pinnacles and the National Park Service urge you to climb safely and "Leave No Trace" -- at Pinnacles and in all other climbing areas in our National Park System.

The vegetation types include riparian woodlands, oak woodlands, wetlands, grasslands, cryptogams, chaparral and coastal sage scrub.
Pinnacles National Monument was created by the National Park Service on January 16, 1908. The Park occupies about 26,000 acres of land in the Gabilan Range of central California. Over 16,000 acres of the Park is set aside as designated wilderness. The Park functions as a regional recreation area. Visitors to the Park may hike on trails, climb rock walls, explore the talus caves or use the campground and picnic facilities.

During summer months, when stream flow diminishes or ceases altogether, standing pools often persist late into the season, creating ideal habitat for breeding populations of many amphibians.

The Pinnacles National Monument project study area contains three main ecologic or geomorphologic areas:   • Region 1 - The West
 • Region 2 - The Northeast
   • Region 3 – The South

The West can be divided into four sub-areas: the Pinnacle Rocks, the West slope of the Chalone Peaks/Pinnacle Rocks, Gloria Valley and the Southwest Hills of the Expanded Area. Of the three regions, the West is most affected by the fog that moves in from the west.

The Pinnacle Rocks are a series of very large jagged irregular volcanic rock outcrops, towers  and pinnacles running in a general northeast to southwest trend. The rock faces have little to no vascular vegetation.

The Northeast can be divided into six sub-areas: Bickmore Canyon, the Northeast Dry Chaparral, the Highway 25 Corridor, Old Pinnacles Mixed Chaparral, North Chalone Creek and Bear Gulch-Bear Valley.

The South is divided into four sub-areas: the Mount Defiance-Frog Creek area, the Far South, South Chalone Creek and the Eastern Extension.

The history of land use within the Upper Chalone Creek Watershed predates the period commonly known as “historical” (1769 to present), although most anthropogenic impacts are typically and mistakenly associated only with the historic period. This part of California has been occupied by humans for at least 10,000 years, possibly longer. Sometime between 2,000 and 3,000 years ago, the ancestors of the present Ohlone Indians migrated into California’s central coast region, bringing with them new technologies which included the processing and storage of durable grains and nuts, especially acorns, which became a staple of their civilization. These innovation allowed them to evolve a complex social structure which was capable of supporting a relatively large population.

Pinnacles National Monument explores the formation of these unique geologic formations: how scientists surmise the Pinnacles area has been carried 195 miles north of its original location by the inexorable creep of the earth’s tectonic plates. The ancient volcano was split in half; remains can still be found in southern California’s Neenach Formation. Erosion’s slow sculpting of the rocks resulted in the landforms we see today.

Shield volcanoes

Shield volcanoes are tall and broad with flat, rounded shapes. They have low slopes and almost always have large craters at their summits.Shield volcanoes can be very big. An example is Mt. Kilauea (in Hawaii, USA).
Shield volcanoes are built almost entirely of fluid lava flow. Flow after flow pours out in all directions from a central summit vent, which builds a broad, gently sloping cone - much like a warrior's shield or a plateau.As the lava cools, it dips down in the center leaving sloped sides, like a bowl or a shield.These volcanoes do not explode the way composite volcanoes do; instead, lava just flows out of them.Their eruptions consist of hot, flowing basaltic lava that travels a long way before it solidifies.
Many volcanoes that form above hot spots are shield volcanoes.
Shield volcanoes have much smaller eruptions producing less ash. However they pour out a lot more lava over a long period of time.
Olympus Mons is, a giant shield volcano on Mars. It is believed to be the largest volcano in the solar system.
Mauna Loa, a shield volcano on the "big" island of Hawaii, is the largest single mountain in the world, rising over 30,000 feet above the ocean floor and reaching almost 100 miles across at its base.
However some volcanoes like Mauna Loa stay active and erupt much more often.The Hawaiian volcano of Kilauea has thrown lava nearly 2,000 feet into the air.

Composite volcanoes

Composite volcanoes have a principal conduit system through which magma from a reservoir deep in the Earth's crust rises to the surface repeatedly to cause eruptions.Composite volcanoes, sometimes called stratovolcanoes, tend to erupt explosively because of the silica-based nature of magmas associated with these volcanoes.

Composite volcanoes often form the largest and tallest volcanoes. They are the most explosive and dangerous of the types of volcanoes.
Most of the tall volcanoes, like Mount St. Helens and Mount Rainier in Washington and Mount Fuji in Japan are composite volcanoes. These volcanoes usually have a big explosion when they erupt, and in-between eruptions you might not even be able to tell they are volcanoes, because they are very quiet and look just like other
mountains.
Shape is largely a function of slope angle; at the one
extreme are very shallow slopes that characterize shields, and on the other are the steeper slopes that characterize cones and domes. Among the smaller edifices are cinder cones and domes, which are typically monogenetic (formed from a single eruption episode).

Compared with caldera systems, composite volcanoes erupt smaller volumes more frequently and less explosively, which likely inhibits the long-term extreme differentiation, which typifies caldera-forming magmas.Young stratovolcanoes are typically steep sided and symmetrically cone shaped. There are several active stratovolcanoes in North America. Since 1980 Mount Saint Helens in Washington has become the most familiar.dimension built of alternating layers of lava flow, volcanic ash and cinders.

Famous composite volcanoes include Mount Fuji in Japan, Mount Shasta and Mount Lassen in California, Mount St. Helens and Mount Rainier in
Washington State, Mount Hood in Oregon, and Mount Etna in Italy.
Composite volcanoes will rise as much as 8,000 feet above their base. Most composite volcanoes have a crater at the summit, which contains a central vent or a clustered group of vents.Most volcanoes on Earth are of this type. Stratovolcanoes kill more people than any other type of volcanoes - this is because of their abundance on Earth and their powerful mudflows.