| Pacific Ranges | |
|---|---|
| French:Chaînons du Pacifique | |
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| Highest point | |
| Peak | Mount Waddington |
| Elevation | 4,019 m (13,186 ft) |
| Coordinates | 51°22′30″N125°15′30″W / 51.37500°N 125.25833°W /51.37500; -125.25833 |
| Dimensions | |
| Area | 108,237 km2 (41,791 mi2) |
| Geography | |
 Pacific Ranges as defined in S. HollandLandforms of British Columbia | |
| Location | British Columbia,Canada |
| Parent range | Coast Mountains |
ThePacific Ranges are the southernmost subdivision of theCoast Mountains portion of thePacific Cordillera. Located entirely withinBritish Columbia, Canada, they run northwest from the lower stretches of theFraser River toBella Coola andBurke Channel,[1] north of which are theKitimat Ranges. The Coast Mountains lie between theInterior Plateau and theCoast of British Columbia.[2][3]
The Pacific Ranges include four of the five major coastal icecaps in the southernCoast Mountains. These are the largest temperate-latitude icecaps in the world and fuel a number of very major rivers (by volume, not length). One of these containsMount Waddington, the highest summit entirely withinBritish Columbia. Also within this region isHunlen Falls, among the highest inCanada, located inTweedsmuir South Provincial Park.
Other than logging and various hydroelectric developments, and a large ski resort atWhistler, most of the land in the range is completely undeveloped. Historically, in the southern part of the range, mining was important at various times in the Lillooet, Bridge River and Squamish areas, and large pulp and paper mills at Powell River, Port Mellon and Woodfibre. The largest hydroelectric development in the Pacific Ranges is theBridge River Power Project, though smaller hydro plants are on the Stave River-Alouette Lake system in Mission and Maple Ridge, the Daisy Lake-Squamish River division of the Cheakamus Powerhouse, and another power dam and power plant atClowhom. Although the range was extensively surveyed for possible rail routes, only that of the Pacific Great Eastern (now part of CN) was eventually built; the Homathko River-Bute Inlet route, however, was one of the two main choices in the deliberations of the CPR's routing.
The Pacific Ranges are part of the southern portion of theCoast Plutonic Complex and has been characterized by rapid rates of uplift over the past 4 million years, which has led to relatively high rates oferosion.
TheGaribaldi Volcanic Belt is within the Pacific Ranges, which is avolcanic belt formed by thesubduction of theJuan de Fuca Plate (a remnant of the much largerFarallon Plate) under theNorth American Plate along theCascadia subduction zone. The belt is the northern extension of theCascade Volcanic Arc in theUnited States (which includes the volcanoesMount St. Helens andMount Baker) and contains the most explosive young volcanoes in Canada. The eruption styles in the belt range fromeffusive toexplosive, with compositions frombasalt torhyolite. Morphologically, centers includecalderas,cinder cones,stratovolcanoes and small isolatedlava masses. Due to repeated continental and alpine glaciations, many of the volcanic deposits in the belt reflect complex interactions betweenmagma composition, topography, and changing ice configurations. The most recent major catastrophic eruption in the Garibaldi Volcanic Belt was from theMount Meager massif 2,350BP, which is Canada's most recent major catastrophic eruption.
The Garibaldi Volcanic Belt contains two extra volcanic fields, theFranklin Glacier Complex and theSilverthrone Caldera, which lie 140 and 190 km northwest of the main volcanic belt.
TheCascadia subduction zone is a 680 mi (1,094 km) longfault, running 50 mi (80 km) off the west-coast of thePacific Northwest fromnorthern California toVancouver Island. The plates move at a relative rate of over 0.4 inches (10 mm) per year at a somewhat oblique angle to the subduction zone.
Unlike most subduction zones worldwide, there is nooceanic trench present along thecontinental margin inCascadia. Instead,terranes and theaccretionary wedge have been uplifted to form a series of coast ranges and exotic mountains. A high rate of sedimentation from the outflow of the three major rivers (Fraser River,Columbia River, andKlamath River) which cross the Cascade Range contributes to further obscuring the presence of a trench. However, in common with most other subduction zones, the outer margin is slowly being compressed, similar to a giantspring. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very largeearthquakes, such as the 8.7–9.2 Mw Cascadia earthquake of 1700.
Many smaller ranges and subranges are not listed at present.
(Other than theWaddington Range these are also considered to be "ranges" but are listed separately here because of their unique character).
List is incomplete
Some Protected areas, recreation areas and other non-park preservation areas are not listed.
Many relatively unknown rivers of considerable size along the coastal flank of the range are not listed, partly because they are largely unknown and also very difficult to access. For a full listing of rivers in the Pacific Ranges, seeList of rivers of the Pacific Ranges.
