Open Library - открытая библиотека учебной информации

Открытая библиотека для школьников и студентов. Лекции, конспекты и учебные материалы по всем научным направлениям.


География Antarctica
просмотров - 112

Read and translate the text

Practise reading the following words

Weddell Sea, Antarctic (Palmer) Peninsula, Cape Horn, Ross Sea, Ross Barrier, Gondwanaland, outward, downward, varieties, enormous, supercontinent, concentrically, persistent, steep-sided, interior, creatures, compactness, altitude.

Antarctica, fifth in size among the world’s continent, lies concentrically about the South Pole, with a landmass almost wholly covered by a vast ice sheet. The area of the continent is about 14,200,000 square kilometers. The southern portions of the Atlantic, Indian and Pacific oceans form the Antarctic ocean around Antarctica.

Antarctica is a compact, mountainous plateau having only three pronounced irregularities along the coastline: the Weddell Sea facing the Atlantic; the Antarctic (Palmer) Peninsula thrust northward in the direction of Cape Horn to latitude 630; and farther west the deep indentation of Ross Sea, which supports on its inner reaches a broad expanse of enduring shelf called ‘Ross Barrier’. This is the largest area of persistent, water-born ice, with dimensions of about 300 by 500 miles. From place to place huge glaciers, tongues of inland ice, extend downward through rocky, steep-sided coastal valleys from the interior high plateau to the sea.

All of Antarctica, save a scattering of high, angular peaks and negligible, discontinuous tracts of coastal lowland is covered with a deep mantel of enduring ice and snow. It is estimated that 90 per cent of the world’s ice is concentrated in this single, enormous expanse. Most of it stands at high altitude, averaging more than 6,000 feet above the sea. The thickness of the ice cap has been seismically measured to average about 8,000 feet.

Antarctica is a continent almost devoid of lakes, without rivers, marshes, having no soil, no forests, no grasslands, nor any deserts of the sort found in milder latitudes. Its fauna are creatures of the sea, such as certain varieties of whales, giant Weddel seal, flying birds like the albatross, petrel, etc. The most prominent inhabitant of Antarctica is the penguin. A flightless bird, it lives on the pack ice and in the oceans around Antarctica, and breeds on the land or ice surfaces along the coast. Most typical are the Adelie and emperor penguins. Plant life includes over a hundred species of lichens and mosses found on bare rock areas along the coast. Algae often color the snow of coastal tracts and are found in a few freshwater lakes.

The size, latitude, altitude and comparative compactness of Antarctica, the height and steepness of its coastal margins, the broad embayments of Ross Sea and Weddell Sea, and the tapering projection of a single peninsula, all surrounded by the unfrozen sea, combine to establish the essential climatic character of the South Polar ice cap.

Antarctic weather may be described as a combination of very cold air, high winds, and blowing snow. Antarctica’s coldest temperatures often reach –730 C. The almost constant wind intensifies the cold. The snow that falls never melts and the pressure caused by the enormous weight of the snow turns it to ice. Despite the large amounts of ice and snow that cover the continent, geographers regard Antarctica as desert because it receives little precipitation.

Antarctica was a central part of the former supercontinent Gondwanaland. As Gondwanaland broke apart to form the continents of the southern hemisphere, Antarctica drifted from the tropical zone to its present polar position. Within the mountains are found many coal deposits and fossil remains related to the earlier tropical climate of Antarctica.