I Physiographic divisions. Relief

IV The main industries and cities.

III Climate.

II Major Rivers and Lakes.

I Physiographic divisions. Relief.

Lecture 10 The USA physical geography

The geography of the United States varies across their immense area. The conterminous United States may be divided into eight broad physiographic divisions:

1. from east to west, the Atlantic-Gulf Coastal Plain – the coastal regions of the eastern and southern parts includes the continental shelf, the Atlantic Coast and the Gulf Coast;

2. the Appalachian Highlands - lying on the eastern side of the United States, it includes the Appalachian Mountains (Аппалачи), the Watchung Mountains, the Adirondacks and New England province originally containing the Great Eastern Forest. The Appalachian Mountains, ancient mountains, extend southwest from SE Canada to the Gulf Coastal Plain in Alabama. In E New England, the Appalachians extend in a few places to the Atlantic Ocean, contributing to a rocky, irregular coastline. The Appalachians and the Adirondack Mountains (Адирондак) of New York (which are geologically related to the Canadian Shield) include all the chief highlands of E United States; Mt. Mitchell (6,684 ft/2,037 m high), in the Black Mts. of North Carolina, is the highest point of E North America.

3. the Interior Plains - part of the interior continental United States, it includes much of what is called the Great Plains;

4. the Interior Highlands - also part of the interior continental United States, this division includes the Ozark Plateau (плато Озарк) and the Ouachita Mountains (Уошито);

5. the Rocky Mountain System - one branch of the Cordilleran system lying far inland in the western states. This geologically young and complex system extends into NW United States from Canada and runs S into New Mexico. There are numerous high peaks in the Rockies (Скалистые горы); the highest is Mt. Elbert (14,433 ft/4,399 m). The Rocky Mts. are divided into four sections - the Northern Rockies, the Middle Rockies, the Wyoming (Great Divide) Basin, and the Southern Rockies.

6. the Intermountain (Межгорный) Region - also divided into the Columbia Plateau, the Colorado Plateau and the Basin and Range Province, it is a system of plateaus, basins, ranges and gorges between the Rocky and Pacific Mountain Systems. It is the setting for the Grand Canyon, the Great Basin and Death Valley. The lowest point in North America, in Death Valley (282 ft/86 m below sea level), is there. The largest basin in the region is the Great Basin, an area of interior drainage (the Humboldt River is the largest stream) and of numerous salt lakes, including the Great Salt Lake.

7. the Pacific Mountain System - the coastal mountain ranges and features in the west coast of the United States. The Cascade Range, with its numerous volcanic peaks extends S from SW Canada into N California, and from there is continued south by the Sierra Nevada, a great fault block. Mt. Whitney (14,495 ft/4,418 m), in the Sierra Nevada, is the highest peak in the conterminous United States.

8. the Laurentian Uplands (Лаврентийская возвышенность)- a part of the Canadian Shield, that extends into the United States from Canada in the Great Lakes region. It is an area of little local relief, with an irregular drainage system and many lakes, as well as some of the oldest exposed rocks in the United States.

Alaska may be divided into four physiographic regions; they are, from north to south, the Arctic Lowlands, the coastal plain of the Arctic Ocean; the Rocky Mountain System, of which the Brooks Range is the northernmost section; the Central Basins and Highlands Region, which is dominated by the Yukon River basin; and the Pacific Mountain System, which parallels Alaska's southern coast and which rises to Mt. McKinley (Denali; 20,320 ft/6,194 m), the highest peak of North America. The islands of SE Alaska and those of the Aleutian Islands chain are partially submerged portions of the Pacific Mountain System and are frequently subjected to volcanic activity and earthquakes. These islands, like those of Hawaii, are the tops of volcanoes that rise from the floor of the Pacific Ocean. Mauna Kea and Mauna Loa on Hawaii are active volcanoes; the other Hawaiian islands are extinct volcanoes.

Elevation extremes:

Lowest point: Death Valley, Inyo County, California -282 ft (−86 m) below sea level.

Highest point: Mount McKinley, Denali Borough, Alaska +20,320 ft (6,194 m) above sea level.

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