The Andes Mountains, known in South America as
Cordilleras de los Andes, define western and northern
South America, running from Tierra del Fuego to
Trinidad, the major ridges bending northeast when
they reach Colombia and continuing into Venezuela,
while one ridge continues northward into Panama. The
Andes form a complex series of parallel chains divided
by a flat tableland area, called altiplano, normally at
about 4,000 m (13,120 ft) elevation. This tableland is
the site of several isolated high- elevation lakes, the
largest being Lake Titicaca, which sits on the border
between Peru and Bolivia.
Characteristic of young, geologically active
mountains, the Andes are ruggedly tall peaks routinely
ranging from 2,000 m (6,560 ft) to 6,000 m (19,680 ft)
tall. There are over a dozen peaks in excess of 6,100
m (20,000 ft), the tallest being Mt. Aconcagua in
Argentina, at 6,962 m (22,834 ft). You must go trekking
in the Himalayas or Pamirs of Asia to find mountains
of similar stature (Mt. Everest is about a mile higher
than Aconcagua).
Where the Andes cross the equator, the snowline
begins at elevations between about 4,500 and 5,000 m
(14,760– 16,400 ft). As you move progressively north or
south of the equator, the climate becomes more severe
and snowline occurs at increasingly lower elevations.
Approaching the southernmost part of the Andes,
snowline is at only 1,000 m (3,280 ft).
Geography of the Cordilleras
The Andes Mountains extend well beyond the
climatic zone of the Neotropics, beginning at the
frigid southern tip of South America, at Tierra del
Fuego (Land of Fire). This land was once inhabited
by the indigenous Yahgan (Yámana) Indians, a
people known to Charles Darwin, who encountered
them when the Beagle visited the region. The Yahgan
inhabited an extremely harsh climate but were
apparently physiologically capable of sleeping on
snow, exposed to the open environment.
Ships rounding Cape Horn face continually strong
westerlies, gale- force winds that create among the
roughest seas known. It is here that Captain FitzRoy of
the hms Beagle discovered the Beagle Channel; as he
sailed through the channel, FitzRoy noted a mountain,
which he named Mt. Darwin (2,438 m/7,996 ft), after
the Beagle’s most distinguished passenger.
The Andes stretch northward, a relatively narrow
ridge along the border between Chile and Argentina.
Some of the tallest peaks occur east of the Chilean cities
of Valparaíso and Santiago, near the mountain city of
Mendoza, Argentina, south of the Tropic of Capricorn.
Here, in close proximity, one finds Mt. Aconcagua
(6,962 m/22,834 ft), Mt. Tupungato (6,802 m/22,310 ft),
and Mt. Mercedario (6,772 m/22,211 ft), and the Andes
begin to widen into a series of ridges with extensive
tracts of altiplano in between. The lower mountain
slopes are temperate in climate, not yet tropical, and
precipitation varies, depending on elevation, from
between 25 and 102 cm (approx. 10– 40 in) annually.
West of the mountain ridge, in northern Chile near the
city of Copaipó, the Atacama Desert begins, an arid
coastal region extending northward almost 3,218 km
(2,000 mi), finally becoming the Sechura Desert on the
border between Peru and Ecuador.
Where the countries of Chile, Peru, and Bolivia meet,
the topography of the Andes becomes increasingly
complex, as the mountain range diversifies into a
series of ridges with vast area of intervening high-
elevation altiplano. It is here that there was once an
extensive inland sea, the legacy of which remains as
salt flats (Salar de Uyuni and Salar de Coipasa), as
well as Lake Titicaca and a few other scattered, small
lakes. The main chain of the Andes, the Western
Cordillera, continues west of the salt lakes and Lake
Titicaca toward Machu Picchu (the great city of the
Inca) and Cusco, Peru. East of Titicaca, the Cordillera
Real and Cordillera de Carabaya gradually descend
on their eastern slopes through zones of humid
montane forest, eventually terminating as tropical
lowland rain forest in western Bolivia and eastern
Peru. Throughout the Andes Mountains, modern
descendants of the Inca continue to thrive in the high
elevations (plate 13- 23).
In Ecuador and Colombia, the Andes diverge into
three major ridges, the Western, Central, and Eastern
Cordilleras. The Western Cordillera extends north
to Central America. The Central Cordillera extends
roughly 800 km (approx. 500 mi) northeastward
through Colombia. The Eastern Cordillera passes
through Bogotá toward the northeast, dividing into
two ridges, the Cordillera de Perijá and the Cordillera
de Mérida. The former continues northeastward in
Colombia and terminates on the Guajira Peninsula
bordering the Caribbean Sea, while the latter bends
further northeast, passing into Venezuela, terminating244 chapter 13 scaling the andes