السبت، 17 نوفمبر، 2012

Alaska's geography

The Land
Click for larger imageAlaska's geography can be categorized into four main areas including two mountain ranges, a central plateau, and the Arctic slope or coastal plain.Click for larger imagePacific Mountain System: In the south and southeast, the Pacific Mountain system is a major feature and is divided into many subdivisions. In general, the Pacific Mountain System runs from the Aleutian Islands down through south central Alaska down the Pacific coast to southern California. In southeast Alaska, a strip of land about 400 miles long and about ten to 150 miles wide comprises what is known as the Alaska Panhandle bordering the Pacific Ocean and the Gulf of Alaska. The Pacific Mountain System includes, from the south, the Saint Elias Range, the Wrangell Mountains, the Chugach Mountains and the Kenai Mountains (West to the Kenia Peninsula and Kodiak Island), the Talkeetna Mountains, and the Alaska Range home of Mt. McKinley.
Click for larger imageExtending southwest from the southern Alaska mainland and the Alaska Range, the Alaska Peninsula and the Aleutian Islands are supported by the Aleutian Mountain Range. The Aleutians include 14 large islands and about 55 small islands. The largest islands are Unimak, Unalaska, and Umnak. The Aleutian Range extends 1,600 mile, from Mount Spurr, across Cook Inlet from Anchorage, to Attu Island near the Asian continent and contains many active volcanoes. This range is home to the Valley of Ten Thousand Smokes, created when Novarupta erupted in 1912. The Valley of Ten Thousand Smokes was named for the numerous fumaroles in the area. Fumaroles are holes in the earth that release hot gas steam into the air.
Within the Pacific Mountain System are two distinct lowland areas; the Copper River Basin and the Susitna-Cook Inlet lowland. The Copper River Basin lies between the Chugach and Wrangell mountains and during the ice age was once the site of a large lake. Today it is a forested woodland. The Susitna-Cook Inlet extends north and east from Anchorage and is mostly forested. It also includes the fertile farmland known as the Matanuska Valley.
Click for larger imageCentral Uplands and Lowlands: This area is sandwiched between the Alaska Range of the Pacific Mountain System in the south and the Brooks Range of the Rocky Mountain System of Alaska in the north. Its geography makes up the largest land area in Alaska. Bordered on the west by Canada, the Central Uplands and Lowlands region extends westward to include the Seward Peninsula and the Kuskokwim River area of southwestern Alaska. The Central Upland and Lowlands area is marked by low, rolling hills and swampy river valleys such as the those of the Koyukuk, Kuskokwim, Tanana, and Yukon rivers.
Click for larger imageRocky Mountain System of Alaska: North of the Central Uplands and Lowlands area is the Rocky Mountain System of Alaska. This area is comprised of the Brooks Range and the Brooks Range foothills. The Brooks Ranges is comprised of glacier-made mountain peaks that rise to 9,000 feet above sea level in the east with lower elevations in the west.
Arctic Coastal Plain: The northernmost geographic area of Alaska is called the Arctic Coastal Plain. This area lies north of the Rocky Mountain System and slopes gradually toward the Arctic Ocean. This is the land of permafrost (Permanently frozen ground) and no trees can manage to grow in this area. The surface of the ground does thaw enough in the spring to allow the growth of grass and wildflowers however. This area is called the tundra)

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