Geography of Guyana: Encyclopedia II - Geography of Guyana - Terrain

Geography of Guyana - Terrain

The coastal plain, which occupies about 5 percent of the country's area, is home to more than 90 percent of its inhabitants. The plain ranges from five to six kilometers wide and extends from the Courantyne River in the east to the Venezuelan border in the northwest.

The coastal plain is made up largely of alluvial mud swept out to sea by the Amazon River, carried north by ocean currents, and deposited on the Guyanese shores. A rich clay of great fertility, this mud overlays the white sands and clays formed from the erosion of the interior bedrock and carried seaward by the rivers of Guyana. Because much of the coastal plain floods at high tide, efforts to dam and drain this area have gone on since the 1700s.

Guyana has no well-defined shoreline or sandy beaches. Approaching the ocean, the land gradually loses elevation until it includes many areas of marsh and swamp. Seaward from the vegetation line is a region of mud flats, shallow brown water, and sandbars. Off New Amsterdam, these mud flats extend almost twenty-five kilometers. The sandbars and shallow water are a major impediment to shipping, and incoming vessels must partially unload their cargoes offshore in order to reach the docks at Georgetown and New Amsterdam.

A line of swamps forms a barrier between the white sandy hills of the interior and the coastal plain. These swamps, formed when water was prevented from flowing onto coastal croplands by a series of dams, serve as reservoirs during periods of drought.

The white sand belt lies south of the coastal zone. This area is 150 to 250 kilometers wide and consists of low sandy hills interspersed with rocky outcroppings. The white sands support a dense hardwood forest. These sands cannot support crops, and if the trees are removed erosion is rapid and severe. Most of Guyana's reserves of bauxite, gold, and diamonds are found in this region.

The largest of Guyana's three geographical regions is the interior highlands, a series of plateaus, flat-topped mountains, and savannahs that extend from the white sand belt to the country's southern borders. The Pakaraima Mountains dominate the western part of the interior highlands. In this region are found some of the oldest sedimentary rocks in the Western Hemisphere. Mount Roraima, on the Venezuelan border, is part of the Pakaraima range and, at 2,762 meters, is Guyana's tallest peak. Farther south lies the Kaieteur Plateau, a broad, rocky area about 600 meters in elevation; the 1,000-meter high Kanuku Mountains; and the low Acarai Mountains situated on the southern border with Brazil.

Much of the interior highlands consist of grassland. The largest expanse of grassland, the Rupununi Savannah, covers about 15,000 square kilometers in southern Guyana. This savannah also extends far into Venezuela and Brazil. The part in Guyana is split into northern and southern regions by the Kanuku Mountains. The sparse grasses of the savannah in general support only grazing, although Amerindian groups cultivate a few areas along the Rupununi River and in the foothills of the Kanuku Mountains.

Adapted from the Wikipedia article "Terrain", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki