Coast Range Arc

The Coast Range Arc was a large volcanic arc system, extending from northern Washington through British Columbia and the Alaska Panhandle to southwestern Yukon. The Coast Range Arc lies along the western margin of the North American Plate in the Pacific Northwest of western North America. Although taking its name from the Coast Mountains, this term is a geologic grouping rather than a geographic one, and the Coast Range Arc extended south into the High Cascades of the Cascade Range, past the Fraser River which is the northward limit of the Cascade Range proper.

The Coast Range Arc formed as a result of subduction of the Kula and pre-existing Farallon Plates. It is most famous for being the largest granitic outcropping in North America, which then it is usually referred to as the Coast Plutonic Complex or the Coast Mountains Batholith. It is a coast-parallel continental volcanic arc similar to the Andes of South America and the largest continential volcanic arc fossil in the world.

Coast Range

Coast Range or Coastal range may refer to:

California Coast Ranges

The Coast Ranges of California span 400 miles (640 km) from Humboldt County, California south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains.

Physiographically, they are a section of the larger Pacific Border province, which in turn are part of the larger Pacific Mountain System physiographic division. UNESCO has included the "California Coast Ranges Biosphere Reserve" in its Man and the Biosphere Programme of World Network of Biosphere Reserves since 1983.

Physiography

The northern end of the California Coast Ranges overlap the southern end of the Klamath Mountains for approximately 80 miles on the west. They extend southward for more than 600 miles to where the coastline turns eastward along the Santa Barbara Channel, around the area of Point Conception. Here the southern end meets the Los Angeles Transverse Ranges, or (Sierras de los Angeles). The rocks themselves that comprise the mountains are of a great variety and widely varying geologic ages. Most of the rocks were formed during the Tertiary, Cretaceous and Jurassic periods. Most were deposited on the sea bottom as sediments, but in many places also had the cracks, crevices and other gaps infused with molten lava or other masses of igneous rock, which were forced in molten condition into the sedimentary rocks. All of the range has been folded and faulted during several periods, with erosion of the softer rock giving much of the current appearance.

Coast Range (EPA ecoregion)

The Coast Range ecoregion is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Washington, Oregon, and California. It stretches along the Pacific Coast from the tip of the Olympic Peninsula in the north to the San Francisco Bay in the south, including Grays Harbor, Willapa Bay, and the Long Beach Peninsula in Washington, the entire length of the Oregon Coast, and the Northern California Coast. Named for the Coast Range mountains, it encompasses the lower elevations of the Olympic Mountains, the Oregon Coast Range, the Californian North Coast Ranges, and surrounding lowlands.

The low mountains of the ecoregion are covered by highly productive, rain-drenched evergreen forests that are home to the three tallest conifer species in the world: Coast redwood,Coast Douglas-fir, and Sitka spruce. Historically, Sitka spruce forests dominated the fog-shrouded coast, while a mosaic of western redcedar, western hemlock, and seral Douglas-fir blanketed the inland areas. Today, Douglas-fir plantations are prevalent on the intensively logged and managed landscape. Lithology influences land management strategies; slopes underlain by sedimentary rock are more susceptible to failure following clearcutting and road building than those underlain by volcanic rock.