Andes Mountains

The andes mountains are one of the greatest mountain ranges on earth, superseded in height only by the Himalayas. They form an enormous meteorological barrier along the spine of South America, running along the western side of the continent from Columbia south to Chile for over 4,000 miles (over 7,000 kilometers).

The Andres have over 50 mountains that exceed 20,000 feet (6,1000 meters) in height; only the Himalayas are taller. Mount Aconcagua, Argentina, only 65 miles west of Santiago, Chile at 22,831 feet (6,959 meters), is the tallest mountain in the Western Hemisphere.

Passes across the Andres usually are very high. At its widest in the Bolivian section it is over 300 miles (500 kilometers) across from east to west.

From the peaks of the Andes flow the Amazon, Orinoco, and Parana-La Plata Rivers. The Pacific side is arid in the central section range. However, the eastern side quickly descends into jungles or swamps.

There are volcanoes in three areas, which have contributed to the formation of the range. Much of the range is composed of faulted and folded rock.

Throughout much of the Andes, glaciation has shaped the mountains and valleys. There many fiords and several active glaciers in the south on the Pacific side. Glaciers were once active in other areas, even in the high elevations at the equator.

The Andes do not form a single mountain chain, but are made up of a number of ranges that are loosely joined together. In the northern section in Columbia, the Cordillera Occidental, Cordillera Central, and the Cordillera Oriental are the major ranges of the Andes.

The Cordillera Oriental runs northward as the Sierra de Perija y Motilones and the Sierra Nevade de Merida, which extend into Venezuela and on to Trinidad. Geologists disagree whether the highlands of Venezuela and Trinidad are part of the Andes. The Cordillera Central and Occidental extend into Ecuador, where a rift valley bordered by volcanoes forms a series of high basins.

The central section of the Andes extends through southern Ecuador to northern Chile and Argentina. The area is a vast highland region with many plateaus and basins formed by separate mountain ranges and volcanoes. There are eastern and western cordilleras that rim the basins and plateaus in between. The Cordillera de los Angles on the west is a chain of volcanoes, most of which are extinct.

In Bolivia lies Lake Titicaca in the Altiplano. Its high basins are above 12,000 feet (3,700 meters), and is the home of numerous Indians. Southward is the Puna de Atacma, much of which is in Argentina. The area is arid, cold, and windswept.

The southern section of the Andes runs from 27 degrees south to Tierra del Fuego. This section has some of the highest peaks, with passes at the 10,000- to 15,000-foot level (3,000 to 4,600 meters). South of 39 degrees south is a vast lake district divided between Argentina and Chile. Shaped by glacial action, the Chilean area has twelve major lakes and many smaller ones with volcanoes and primeval forests. The Argentina lake district is actively used for recreation.

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