Animal species include the roadrunner, Gila monster, and rattlesnake. In addition to mountains, deserts, and forests, the northern part of the western region of North America also has the richest deposits of oil and natural gas on the continent.
Most of these deposits are located offshore, in the Arctic and Pacific Oceans. Great Plains The Great Plains lie in the middle of the continent. Deep, rich soil blankets large areas of the plains in Canada and the United States. The Great Plains are also home to rich deposits of oil and natural gas. Much of the fertile soil was formed from material deposited during the most recent glacial period. This ice age reached its peak about 18, years ago.
As glaciers retreated, streams of melted ice dropped sediment on the land, building layers of productive soil. The grassland or prairie regions of the Great Plains make up the largest biome in North America.
Extreme weather prevents the growth of large plants but is perfectly suited to the native grasses that dominate the region.
Native grasses vary in size from 2 meters 7 feet in tallgrass prairie s to only 20 or 25 centimeters 8 or 10 inches in shortgrass prairies. Native animal species include bison, prairie dogs, and grasshoppers. Canadian Shield The Canadian Shield is a raised but relatively flat plateau. It extends over eastern, central, and northwestern Canada. The Canadian Shield is characterized by a rocky landscape pocked by an astounding number of lake s. Regional Geology of North America.
Click on images for a larger view. The entire region west of the Great Plains is collective lumped together and are called the Cordilleran Ranges , part of the great chain of mountains that border the Pacific Ocean from Alaska to South America. Evolution of Western North America The following brief synopsis of the geologic evolution of the western half of North America is perhaps the best way to start an examination of the physiographic regions of the western United States Figure At depth, ancient crystalline basement rocks of Precambrian age underlie most of the United States.
Crust that had assembled into the stable cratonic shield in Precambrian became foreland basins where sediments accumulated across much of Midwest and Great Plains. At the same time, sediments spread accumulated in the Pacific Ocean margin basin Figure A. In the early Paleozoic Era, shallow seas transgressed and retreated several times onto the stable continental foreland.
However, this just refers to its outcrop area. Rocks of the Shield underlie the interior of the continent beneath the Rocky Mountains , as well as the interior plains of Canada and the United States, where the sedimentary rocks of the Interior Platform cover them.
The Shield is composed of ancient rocks, including some that are among the oldest rocks on Earth possibly more than 4 billion years old. The construction of the Shield involved the collision and build-up of a large number of tectonic plates beginning more than 3 billion years ago and was largely completed by about million years ago. One of the last major plate collisions involved in the assembly of the Canadian Shield is named the Grenville Orogeny. Erosion removed some 20 km of the crust over the next few million years, so that when a great invasion of the sea began about million years ago the landscape was almost flat.
This region is named for the area of the Shield covered by rocks from the Cambrian to Cenozoic eras. They are largely flat-lying, and this is the main reason for the gentle, low-lying topography that characterizes the landscape. It extends northward down the Mackenzie Valley and then eastward across the Arctic Platform, the belt of Arctic Islands lying south of the Northwest Passage.
An area underlain by largely flat-lying Paleozoic sedimentary rocks also extends from southwestern Ontario , down the St. Lawrence Valley and across the Gulf of St.
Lawrence , through Anticosti Island to westernmost Newfoundland. All of these areas underwent a major invasion of the sea at some time between about and million years ago, which lasted until late in the Devonian period, about million years ago.
As a result a gigantic inland sea developed, probably covering almost the entire continent. In it, some of the earliest invertebrate life forms flourished, including trilobites, brachiopods and corals. The limestones that were deposited at this time are well seen in the front ranges of the Rocky Mountains , in the Niagara Gorge and underlying Parliament Hill in Ottawa.
Reefs formed by primitive colonial organisms flourished in the area corresponding to present-day Alberta, and became the host for much of the oil and gas that forms the foundation for the modern economy of that province. At the time the marine invasion of Canada was taking place, the giant continent, Rodinia, was beginning to break up, forming new oceans. Evidence of this can be seen along the continental margins of interior British Columbia and in Newfoundland , where the edge of the Canadian Shield is thin and faulted, and covered with shallow-marine sedimentary rocks.
Off what is now eastern North America an ocean developed that probably rivalled the modern Atlantic Ocean in size, but it did not last long. By the end of Cambrian time about million years ago a process called subduction began.
There are a lot of fun facts about the Western Cordillera. Cordilleras are found in the Americas and Eurasia. In this article, we will share many more fun facts about the Western Cordillera. The exact limits of this cordillera and its subregions, as well as the names of its different characteristics, may vary based on nation or jurisdiction definitions, as well as a scientific discipline; this cordillera is a particularly significant subject in the scientific area of physical geography.
The Pacific Coast Ranges in the west, the Nevadan belt in the center containing the Sierra Nevada , and the Laramide belt in the east all have mountain ranges that run north to south including the Rocky Mountains. Ore deposits in the Western Cordillera are extensive. Copper, lead, zinc, and iron ores are among them.
The Western Cordillera has a marine climate, which means it is heavily impacted by water. Closer to the coast, the temperature is significantly more humid in the fall and winter, resulting in a lot of rain and cooler summers. Inland, there is a lot of snow, especially in the mountains. The Cordillera consists of three primary mountain ranges. The Columbia, Skeena, and Ogilvie mountains make up the Interior mountain chain.
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