Guiana Shield

Guiana Shield

The Guiana Shield [The term "Guiana" or "The Guianas" is often used as a collective name for Guyana, Suriname and French Guiana, and sometimes even includes the portions of Colombia, Venezuela and Brazil which are on the Guiana Shield.] ( _es. Guayana) is one of the three cratons of the South American Plate. It is a 1.7 billion year old Precambrian geological formation in northeast South America that forms a portion of the northern coast. The higher elevations on the shield are called the Guiana Highlands, which is where the impressive and mysterious table-like mountains called tepuis are found. The Guiana Highlands are also the source of some of the world's most spectacular waterfalls such as Angel Falls, Kaieteur Falls and Kuquenan Falls.

The Guiana Shield underlies Guyana (previously British Guiana), Suriname (previously Dutch Guiana) and French Guiana (or Guyane), as well as parts of Colombia, Venezuela and Brazil. The rocks of the Guiana Shield consist of metasediments and metavolcanics (greenstones) overlain by quasi-horizontal layers of sandstones, quartzites, shales and conglomerates intruded by sills of younger mafic intrusives such as gabbros.


There are three upland areas of the Guiana Shield.
# The Guiana Highlands proper are in Venezuela east of the Orinoco and extend across much of westcentral Guyana and into the northern Roraima state in Brazil.
# The Tumucumaque Uplands which are a series of central massifs in an arc from the Wilhelmina Mountains of south-central Suriname, along the southern boundary of Suriname and Guyana, forming the Acarai Mountains of Roraima state and the Tumuc-Humac Mountains of Pará and Amapá states of Brazil. From this arc, the southern uplands slope gently downwards towards the Amazon River and the northern uplands slope gently downwards towards the Atlantic.
# The Chiribiquete Plateau is a sandstone topped plateau with an elevation of Convert|900|m|ft|0|abbr=on that forms the western edge of the shield. The plateau is separated from the eastern Andes by the thick Neogene sediments of the Sub-Andean Trough that runs along the northern and western rim of the Guiana Shield.

The north-central part of the Guiana Highlands is dominated by high flat-topped peaks called tepuis, of the Roraima supergroup and Quasi-Roraima formation, and the rounded granite peaks of the Parguaza and Imataca complexes to the north and southwestern edges of the area. The highest tepui is Monte Roraima at 2,810 m (9,219 ft), on whose top plateau the Venezuela, Guyana and Brazil border tripoint is located, but the Guiana Shield's highest point is Pico da Neblina in Brazil (next to the Venezuelan border) at 2,994 m (9,822 ft). Pico da Neblina is not a tepui but a rather sharp peak, and is located far to the west and south of the area where tepuis are found.


The Guiana Shield is one of the regions of highest biodiversity in the world. The Shield has 1400 vertebrate species and 1680 bird species.Fact|date=March 2008 The Shield is overlain by the largest expanse of undisturbed tropical rain forest in the world. [Hammond, David S. (ed.) (2005) "Tropical Rainforests of the Guianan Shield" CABI Publishing, Wallingford, UK, ISBN ] Guianan rain forest is similar in nature to Amazonian rain forest and known Protected Areas include the Iwokrama Forest of central Guyana and the Kanuku National Park of southern Guyana. In Venezuela the forests are partially protected by the Canaima National Park (VE) and the Kaieteur National Park (GY).


See also

*Canadian Shield
*Caribbean South America
*Monte Roraima
*Pico da Neblina
*Great American Interchange
*Geography of South America

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Shield (geology) — Geologic provinces of the world (USGS)   Shiel …   Wikipedia

  • French Guiana — Infobox French region native name = Région Guyane common name = Guyane image flag size = 130px image logo size = 100px Region flag Region logo capital = Cayenne area = 83,534 area scale = 10 Regional president = Antoine Karam (PSG) (since 1992)… …   Wikipedia

  • Geography of French Guiana — Geographic map of French Guiana French Guiana is an overseas region of France, located on the northern coast of South America between Suriname and Brazil. Contents …   Wikipedia

  • Brazilian Guiana — (ex Portuguese Guiana), is the former name for what now is the states of Amapá, Roraima, north of Pará and Amazonas, including the Guiana Shield in Brazil …   Wikipedia

  • Coat of arms of French Guiana — The coat of arms of French Guiana, a région of France located in South America, displays a gules camp, a sable boat with heraldry oars carrying a bunch of gold situated in an azure river with three silver neuflar flowers two of which are paired… …   Wikipedia

  • continental shield — Any of the large stable areas of low relief (little variation in elevations) in the Earth s crust that are composed of Precambrian crystalline rocks. These rocks are always more than 570 million years old, and some are as old as 2–3 billion years …   Universalium

  • Amazonian shield — The Amazonian shield is located in South America and occupies much of the eastern part of the continent. Smaller areas of Precambrian rocks to the north and south of the Amazonian Shield are the Guiana and Platian shields …   Wikipedia

  • Guyana — Not to be confused with Ghana., or French Guiana. For other uses, see Guyana (disambiguation). Co operative Republic of Guyana[1] …   Wikipedia

  • Guianas, the — Region, northern South America. Located on the Atlantic and Caribbean coasts, it lies between the Orinoco, Negro, and Amazon rivers and covers an area of about 181,000 sq mi (468,800 sq km). It consists of Guyana (formerly British Guiana),… …   Universalium

  • List of shields and cratons — List of shields= *African Shield AKA Ethiopian Shield *Amazonian Shield of central South America *The Angaran Shield of West Siberia *Arabian Nubian Shield *(Western) Australian Shield *Baltic Shield of Scandinavia and Eastern Europe *Canadian… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”