Mountain Ranges, Deserts and Landforms of Canada

Geography

The Rocky Mountains are the easternmost portion of the expansive North American Cordillera. They are often defined as a network stretching from the Liard River in British Columbia south to the headwaters of the Pecos River, a tributary of the Rio Grande, in New Mexico. The Rockies vary in width from 110 to 480 kilometers (70 to 300 miles). The greater Rocky Mountain system functions as a collective network of dozens of distinct subranges divided by high basins and wide rolling tablelands. The Rocky Mountains contain the highest peaks in central North America. The range's highest peak is Mount Elbert in Colorado at 4,401 meters (14,440 feet) above sea level. Mount Robson in British Columbia, at 3,954 m (12,972 ft), is the highest peak in the Canadian Rockies.

Geology

The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces. The oldest rock is Precambrian metamorphic rock that forms the core of the North American continent. There is also Precambrian sedimentary argillite, dating back to 1.7 billion years ago. During the Paleozoic, western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite.

In the southern Rockies, near present-day Colorado, these ancestral rocks were disturbed by mountain building approximately 300 million years ago, during the Pennsylvanian. This mountain-building produced the Ancestral Rocky Mountains. They consisted largely of Precambrian metamorphic rock forced upward through layers of the limestone laid down in the shallow sea.

Ecology and climate

There are a wide range of environmental factors in the Rocky Mountains. The Rockies range in latitude between the Liard River in British Columbia (at 59° N) and the Rio Grande in New Mexico (at 35° N). Prairie occurs at or below 550 meters (1,800 ft), while the highest peak in the range is Mount Elbert at 4,400 meters (14,440 ft). Precipitation ranges from 250 millimeters (10 in) per year in the southern valleys to 1,500 millimeters (60 in) per year locally in the northern peaks. Average January temperatures can range from −7 °C (20 °F) in Prince George, British Columbia, to 6 °C (43 °F) in Trinidad, Colorado. Therefore, there is no single monolithic ecosystem for the entire Rocky Mountain Range.

Instead, ecologists divide the Rockies into a number of biotic zones.

History

Since the last great ice age, the Rocky Mountains were home first to indigenous peoples including the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Coeur d'Alene, Kalispel, Crow Nation, Flathead, Shoshone, Sioux, Ute, Kutenai (Ktunaxa in Canada), Sekani, Dunne-za, and others. Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains.

Geography

The Coast Mountains consists of three subdivisions known as the Pacific Ranges, the Kitimat Ranges, and the Boundary Ranges. The Pacific Ranges are the southernmost subdivision of the Coast Mountains, extending from the lower stretches of the Fraser River to Bella Coola. Included in this subdivision are four of the five major coastal icecaps in the southern Coast Mountains. These are the largest temperate-latitude icecaps in the world and fuel a number of major rivers. Other than logging and a large ski resort at the resort town of Whistler, most of the land in the range is completely undeveloped. Mount Waddington, the highest mountain of the Coast Mountains, lies in the Waddington Range of the Pacific Ranges.

Geology

The Coast Mountains consist of deformed igneous and metamorphosed structurally complex pre-Tertiary rocks. These originated in diverse locations around the globe: the area is built of several different terranes of different ages with a broad range of tectonic origins. In addition, oceanic crust under the Pacific Ocean is being subducted at the southern portion of the range to form a north–south line of volcanoes called the Garibaldi Volcanic Belt, a northern extension of the Cascade Volcanoes in the northwestern United States, and contains the most explosive young volcanoes in Canada. Further north the northwesterly structural trend of the Coast Mountains lies partly in a large continental rift responsible for the creation of several volcanoes.

Geography

The Cascades extend northward from Lassen Peak (also known as Mount Lassen) in northern California to the confluence of the Nicola and Thompson rivers in British Columbia. The Fraser River separates the Cascades from the Coast Mountains in Canada, as does the Willamette Valley from the upper portion of the Oregon Coast Range. The highest volcanoes of the Cascades, known as the High Cascades, dominate their surroundings, often standing twice the height of the nearby mountains. They often have a visual height (height above nearby crestlines) of one mile or more. The highest peaks, such as the 14,411-foot (4,392 m) Mount Rainier, dominate their surroundings for 50 to 100 miles (80 to 161 km).

Geology

The Cascade Range is made up of a band of thousands of very small, short-lived volcanoes that have built a platform of lava and volcanic debris. Rising above this volcanic platform are a few strikingly large volcanoes, like Mount Hood and Mount St. Helens, that dominate the landscape.

The Cascade volcanoes define the Pacific Northwest section of the Ring of Fire, an array of volcanoes that rim the Pacific Ocean. The Ring of Fire is also known for its frequent earthquakes. The volcanoes and earthquakes arise from a common source, namely subduction. In this case, the dense Juan de Fuca Plate plunges beneath the North American Plate at the Cascadia subduction zone.

Ecology

Forests of large, coniferous trees (western red cedars, Douglas-firs, western hemlocks, firs, pines, spruces, and others) dominate most of the Cascade Range. Cool, wet winters and warm, dry summers (largely a result of oceanic influence) favor evergreen species, whereas mild temperatures and rich soils promote fast and prolonged growth.

As a traveler passes through the Cascade Range, the climate first gets colder, then warmer and drier east of the crest. Most of the Cascades' lower and middle elevations are covered in coniferous forest; the higher altitudes have extensive meadows as well as alpine tundra and glaciers. The southern part of the Cascades are within the California Floristic Province, an area of high biodiversity.

History

Before European exploration, First Nations tribes named many peaks, including "Seekseekqua" for Mount Jefferson (Oregon), "M'laiksini Yaina" for Mount McLoughlin, "Tahoma", the Lushootseed name for Mount Rainier, and "Louwala-Clough", meaning "smoking mountain" for Mount St. Helens.

In early 1792, British navigator George Vancouver explored Puget Sound and gave English names to the high mountains he saw. Mount Baker was named for Vancouver's third lieutenant, Joseph Baker, although the first European to see it was Manuel Quimper, who named it la gran montaña del Carmelo ("Great Mount Carmel") in 1790. Mount Rainier was named after Admiral Peter Rainier.

Geography

The region includes the Cariboo Plateau and Chilcotin Plateau, and the adjoining Marble, Clear and Camelsfoot Ranges on its southwestern edge.

It is defined as lying between the Bonaparte River on its southeast, beyond which is the Bonaparte or Kamloops Plateau, part of the Thompson Plateau, and by a line formed by the Dean and West Road Rivers on its northwest (the Nechako Plateau lies to the north of the West Road).

Also included in the Fraser Plateau are the Itcha and Ilgachuz Ranges and the adjoining Rainbow Range, which adjoin the Coast Mountains.

Geography

The Barren Grounds are tundra, and lakes are abundant. It has several long rivers, including the Coppermine, Back, Dubawnt, Kazan, and Thelon. The land in the area is mostly flat, although there are some hills in certain areas.

Geography

Bellot Strait (Ikirahaq) separates the peninsula from Somerset Island to the north. Babbage Bay is on the east coast, as is Abernethy Bay, just to the south. The community of Taloyoak lies in the far south and is the peninsula's only significant population centre. Paisley Bay is on the west coast, as is Wrottesley Inlet (between Paisley Bay and Bellot Strait).

Prior to the detachment of Nunavut in 1999, the Boothia Peninsula and the nearby Melville Peninsula were the only parts of mainland Canada that belonged to the District of Franklin in the then Northwest Territories. The balance of the District of Franklin was all situated within the Arctic Archipelago.

Geology and paleontology

On the peninsula there are outcrops of Early Ordovician rocks, over which Late Ordovician and Silurian rocks are identified (Middle Ordovician is not exposed). Over 1000 conodont fossils of 37 species in 28 genera were collected from these strata. Genera include Teridontus, Cordylodus, Rossodus, Variabiloconus, Semiacontiodus, Drepanoistodus, Parapanderodus, Ulrichodina, Acodus, Colaptoconus, Polyplacognathus, Pteracontiodus, Milaculum and Phosphannulus. Conodont zones are distinguished in Lower and Upper Ordovician.

Geography

Though the five lakes lie in separate basins, they form a single, naturally interconnected body of fresh water, within the Great Lakes Basin. As a chain of lakes and rivers, they connect the east-central interior of North America to the Atlantic Ocean. From the interior to the outlet at the Saint Lawrence River, water flows from Superior to Huron and Michigan, southward to Erie, and finally northward to Lake Ontario. The lakes drain a large watershed via many rivers and contain approximately 35,000 islands. There are also several thousand smaller lakes, often called "inland lakes", within the basin.

Geology

It has been estimated that the foundational geology that created the conditions shaping the present day upper Great Lakes was laid from 1.1 to 1.2 billion years ago, when two previously fused tectonic plates split apart and created the Midcontinent Rift, which crossed the Great Lakes Tectonic Zone. A valley was formed providing a basin that eventually became modern day Lake Superior. When a second fault line, the Saint Lawrence rift, formed approximately 570 million years ago, the basis for Lakes Ontario and Erie was created, along with what would become the Saint Lawrence River.

The Great Lakes are estimated to have been formed at the end of the Last Glacial Period (the Wisconsin glaciation ended 10,000 to 12,000 years ago), when the Laurentide Ice Sheet receded.

Climate

Köppen climate classification Dfa (in southern areas) and Dfb (in northern parts) with varying influences from air masses from other regions including dry, cold Arctic systems, mild Pacific air masses from the west, and warm, wet tropical systems from the south and the Gulf of Mexico. The lakes have a moderating effect on the climate; they can also increase precipitation totals and produce lake effect snowfall.

The Great Lakes can have an effect on regional weather called lake-effect snow, which is sometimes very localized. Even late in winter, the lakes often have no icepack in the middle. The prevailing winds from the west pick up the air and moisture from the lake surface, which is slightly warmer in relation to the cold surface winds above.

Ecology

Historically, the Great Lakes, in addition to their lake ecology, were surrounded by various forest ecoregions (except in a relatively small area of southeast Lake Michigan where savanna or prairie occasionally intruded). Logging, urbanization, and agriculture uses have changed that relationship. In the early 21st century, Lake Superior's shores are 91% forested, Lake Huron 68%, Lake Ontario 49%, Lake Michigan 41%, and Lake Erie, where logging and urbanization has been most extensive, 21%. Some of these forests are second or third growth (i.e. they have been logged before, changing their composition).

Geography

The range lies north of Dawson City, and is crossed by the Dempster Highway.

The area was first surveyed by William Ogilvie and the range subsequently named after him.

The best known mountain peaks of the Ogilvie Mountains are located within Tombstone Territorial Park.

The highest mountain within the range is Mount Frank Rae, at 2,362 m (7,749 ft) in elevation.

Geology

The Devon Ice Cap and the Agassiz Ice Cap on the neighboring Ellesmere Island are two of the largest ice caps in the Arctic Cordillera in the Canadian Arctic, and consist of a substantial fraction of ice not locked away in the Antarctic and Greenland ice sheets. As such, should the entire Devon Ice Cap melt due to global warming, the ice will contribute approximately 1 centimeter to global sea level rise.

The Devon Ice Cap has a dome-like structure and a maximum elevation of 1921 m above sea level at its summit, and the maximum ice thickness is 880 m. There are two distinct regions in the Devon Ice Cap: a 12,050 km2 (4,650 sq mi) ice cap and a 1,960 km2 (760 sq mi) ice-covered region in the west that is geologically inactive.

History

This glacier was advancing in 1890 when viewed by John Muir, and had a large calving front. By 1963, the glacier had advanced 5.6 km (3.5 mi). In 1948, the Taku Fjord had been completely filled in with glacial sediment and the glacier no longer calved. From 1948–1986, the glacier had a positive glacier mass balance driving the advance. From 1987–2009, the glacier has had a slightly negative mass balance, not enough to end the advance, but if it continues will soon slow it.

The icefield, like many of its glaciers, reached its maximum glaciation point around 1700 and has been in retreat since. Much of the icefield is contained within the Tongass National Forest. Since 1948, the Juneau Icefield Research Program has monitored glaciers of the Juneau Icefield.

Climate

While other Alaskan ranges to the south and closer to the coast can receive 250 inches (640 cm) to 500 inches (1,300 cm) of snow, the average snow precipitation on the Brooks Range is reported at 30 inches (76 cm) to 51 inches (130 cm). Due to a changing climate, between the years 1969–2018 the Eastern and Western portions of the Brooks Range have experienced a 17.2% increase in annual precipitation.

As measured at the Anaktuvuk Pass weather station (elevation 770 metres (2,530 ft)), the average summer temperatures are 16 °C (61 °F) as a high and 3 °C (37 °F) as a low. During the winter the average high is −22 °C (−8 °F) while the average low is −30 °C (−22 °F). Polar amplification is a force experienced in this region as global temperatures are rising.

Ecology

The Brooks Range forms the northernmost drainage divide in North America, separating streams flowing into the Arctic Ocean and the North Pacific. The range roughly delineates the summer position of the Arctic front. It represents the northern extent of the tree line, with little beyond isolated balsam poplar stands occurring north of the continental drainage divide. Trembling aspen and white spruce also occur north of the Brooks Range, though they are limited to sites that have been disturbed by human activity. Southern slopes have some cover of black spruce, Picea mariana, marking the northern limit of those trees. As the global mean temperature increases, tree line has been observed to move further north, changing the boundaries of where these trees are found.

History

Bob Marshall explored the North Fork Koyukuk River area of the range in 1929. He named Mount Doonerak, explaining "the name Doonerak I took from an Eskimo word which means a spirit or, as they would translate it, a devil." Marshall described the mountain as, a "towering, black, unscalable-looking giant, the highest peak in this section of the Brooks Range."

Geology

The Columbia Icefield sits on a large area of relatively horizontal layers of rock. Because flat-lying layers erode more slowly than the surrounding tilted areas, the surface remains higher-altitude and therefore colder. The icefield was formed during the Great Glaciation, or Illinoian period (238,000 to 126,000 BCE). The initial advancement of the ice field ended during the latter millennia of the Early Wisconsinan period (73,000 to 62,000 BCE). The next major advance of the ice field occurred during the Late Wisconsinan period (18,000 to 9,000 BCE), which marked the end of the major intercontinental land mass bridges. During the Crowfoot Glacier advance (9,000 to 7,000 BCE), humans were beginning to learn farming along the Tigris, Euphrates, and Nile rivers.

Climate

Columbia Icefield has an alpine climate (Köppen: ETf), because the weather station is located at an altitude of 1,981.20 m (6,500 ft). The average annual temperature is −2.1 °C (28.2 °F). The month of July is the warmest with an average temperature of 9.1 °C (48.38 °F).

History

The view that lay before us in the evening light was one that does not often fall to the lot of modern mountaineers. A new world was spread at our feet: to the westward stretched a vast ice-field probably never before seen by the human eye, and surrounded by entirely unknown, unnamed and unclimbed peaks.

In 1900, former British clergyman James Outram came to the Canadian Rockies to recover his health after a nervous breakdown. The following year he made the first ascent of Mount Assiniboine (3,618 m; 11,870 ft), then considered the "Matterhorn of the Rockies". In 1902, Outram made ten first ascents of peaks over 3,050 metres (10,010 ft) and discovered four new mountain passes in the Columbia Icefield area.