Physical Features and Natural Resources of Colombia
Colombia lies in the "Ring of Fire," an area of seismic instability that surrounds the Pacific Basin and is subject to frequent volcanic eruptions and earthquakes. The country's most notable surface feature is the Andes mountain system, which breaks up the national territory into regions that are isolated from one another and have distinctive characteristics. The three major regions are the Andean mountains and valleys, the Caribbean coast, and the eastern plains.
The Andean Highlands and Valleys
The Andean region occupies about a quarter of Colombia. In the southern part of the country the Andes divide into three separate ranges, which continue northward toward the Caribbean Sea. The western range (Cordillera Occidental) is lowest. Its highest peak is about 4,400 meters (14,436 feet), but most of the other high peaks are between 3,600 and 4,000 meters (11,811–13,123 feet). Its mountains are worn by erosion and are thickly vegetated. The central range (Cordillera Central) is the loftiest and includes permanently snow-covered peaks. The highest of these is 5,429 meters (17,812 feet). The eastern range (Cordillera Oriental) is somewhat lower on average than the central, although its tallest peak -at 5,493 meters (18,022 feet)- is higher than any in the central range.
The basins that separate the three Andean ranges contain Colombia's most important rivers. The Magdalena, which flows northward between the central and eastern ranges and empties into the Caribbean Sea, has been called "the lifeline of Colombia." Between the central and western Andean ranges the Cauca River flows north into the Magdalena.
Climate in the Andean region depends on elevation. The tierra templada, or "temperate" zone, extending from 1,000 to 2,000 meters (3,281–6,562 feet), is warm, with Cali having an average temperature of 73° F (23° C) and Medellín of 68° F (20° C). Santa Fe de Bogotá, in the tierra fría, or "cold" zone above 2,000 meters, has an average temperature of 57° F (14° C). Rainfall in the Andean region is moderate.
The region has extensive level areas that are suitable for agriculture. Among these are the sabana (plain) of Bogotá and the Cauca Valley. In many places, however, the land is either too high and cold or too steep for farming. Many inclines are gentle enough for cultivation but are quickly eroded if deprived of their natural ground cover.
The Andes contain much mineral wealth: coal near Santa Fe de Bogotá and Medellín, some of it of coking quality; emeralds near Santa Fe de Bogotá; gold in the Medellín area; iron ore near Tunja; and petroleum, especially in the Magdalena River valley. The mountain rainfall makes the region the center of Colombia's hydroelectric potential.
The Caribbean Coastal Region
The coastal area bordering the Caribbean makes up about an eighth of the country. This northern region consists for the most part of broad lowlands, including extensive swamps. However, an isolated mountain group -the Sierra Nevada de Santa Marta- contains the nation's highest peaks, reaching 5,775 meters (18,947 feet).
The climate of the Caribbean lowlands is hot and harsh, and tropical diseases are common. The seaport of Barranquilla has an average temperature of 82° F (28° C). The region's rainfall is adequate and seasonally heavy.
The varied coastal terrain includes some good lands for plantation agriculture and grazing. Coal is abundant in the department of La Guajira and near Barranquilla. Nickel is found in the department of Córdoba.
The Caribbean lowlands connect with the narrow Pacific (western) lowlands at the Gulf of Urabá. Much of this hot, wet zone is separated from the Pacific by mountains known as the Serranía de Baudó. The west coast is cut off from the interior by the Cordillera Occidental.
The Eastern Region
The hot, isolated, and thinly populated eastern plains account for almost three fifths of the national territory. This region consists of two quite distinct zones of vegetation. The southern, wetter part lies within the tropical rain forest of the Amazon River basin. Rubber was an important product during the early part of the 20th century. Now, tourist potential and wild animals for zoos are the most important resources. From Leticia, shipping down the Amazon through Brazil to the Atlantic is possible. Agricultural development is difficult because of the tree cover, and the heavy rainfall causes nutrients to leach from the soil when the land is cleared.
The northern part of the eastern region is made up of the open plains (llanos) of the Orinoco River basin. The llanos are tropical grasslands that undergo seasonal flooding. They are suitable for livestock grazing and, in some areas, the cultivation of crops. Major petroleum discoveries have been made in the eastern region. These include some in the Amazon near Ecuador and others in the Orinoco area near Venezuela.