Tepui
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The Tepuis are table-like mountains (mesas) found only in the Guiana highlands. These geological formations tend to be found as isolated entities rather than in mountain range fashion, which makes them the host of a unique array of endemic plant and animal species. Some of the most outstanding tepuis are Autana, Pico da Neblina (the highest one, on the Venezuelan-Brazil border), Auyantepui and Monte Roraima. They are typically composed of Precambrian sandstone rocks, very hard to climb, which rise abruptly from the jungle, giving rise to spectacular natural scenery. Auyantepui in particular is the source of Angel Falls, the world's tallest waterfall.
Origin of the Tepui
The indigenous people called the mesas Tepuis, "Houses of the Gods". They are the remains of a large, quartz sandstone plateau, that once covered the granite basement complex between the north border of the Amazon Basin and the Orinoco, between the Atlantic coast and the Rio Negro. Throughout the course of the Earth's history the plateau was eroded, and the tepuis were formed from the remaining monadnocks.
There are 115 such mesas in the Gran Sabana in the south-east of Venezuela, on the border with Guyana and Brazil, where the highest concentration of tepuis is found. The precipitous mountains tower over the rainforest by up to 1,000 meters. The surface of the mountains display various characteristics. On the top of the mountains grow various types of forests with a wide variety of orchids and Bromeliads species. Erosion and weathering has, over the course of millennia, formed peculiar rock formations and labyrinths.
Flora and Fauna
The plateau of the mesas is completely isolated from the ground forest. On the one hand the altitude causes them to have a different climate from the ground forest, on the other the cliffs are difficult to climb. This isolation has over millennia led to the presence of endemic flora and fauna. The top presents cool temperatures with frequent rainfall, while the base of the mountains have a tropical, warm and humid climate. The isolation has led to the evolution of a different world of animal and plants, cut off from the rest of the world by the imposing rock walls. The Tepuis are often referreed to as the Galápagos Islands of the mainland. The large number of plants and animals are of a unique variety and cannot be found anywhere else in the world. The floors of the mesas are poor in nutrients, which has led to a rich variety of carnivorous plants. The weathered, craggy nature of the rocky ground means no layers of humus are formed. Some of the mesas are pocked with giant sinkholes up to 300 meters in diameter, with sheer walls up to 300 meters deep, containing many species that have evolved in these "islands within islands" unique only to each individual sinkhole. These sinkholes were formed when the roofs of tunnels carved by underground rivers collapsed.
The tepuis, also known as 'islands above the rainforest', are a challenge for researchers, as they are home to a high number of new species which have yet to be described. A few of these mountains are cloaked by thick clouds almost the whole year round. Their surfaces could previously only be photographed by helicopter radar equipment. Humans have still yet to set foot on many of the tepuis.
Most tepuis can be found in the Canaima National Park in Venezuela, which has been classified as a World Heritage Site by UNESCO.
Selected Tepuis
A few of the more notable of the 115 Tepuis are:
- Auyantepui. This well known mesa has a surface area of 700 km². From its surface falls the highest waterfall in the world, the Angel Falls.
- Roraimatepui, also known as Monte Roraima. A report by the noted South American researcher Robert Schomburgk inspired the English author Arthur Conan Doyle to write his novel The Lost World about the discovery of a living prehistoric world full of dinosaurs and primeval plants.
- Kukenamtepui. Kukenam Tepui was considered a holy mountain by the native peoples. Since 1997 it can no longer be climbed, as the precipice and the high plateau are particularly insurmountable.
- Autanatepui. Autana stands 1,300 m above the forest floor. This mountain presents a peculiar cave that runs from one side of the mountain through the other.
- Neblinatepui, also known as Pico da Neblina, is the highest tepui.
- The Ptaritepui. The rock walls of the Ptaritepui are so isolated, that it is assumed that a particularly high number of endemic plant and animal species may be found there.
See also
References
- Much of the text of this article comes from [the corresponding German-language Wikipedia article], retrieved on 16th February 2006, which uses the following sources:
- * Uwe George: Inseln in der Zeit. GEO - Gruner + Jahr AG & Co., Hamburg, ISBN 3570062120.
- * Roland Stuckardt: Sitze der Götter. terra - Heft 3/2004, Tecklenborg Verlag, Steinfurt.
External links
- [The Making of the Tepuis Film : "The Living Edens : The Lost World"]
- [Mongabay.com] -- pictures from Tepuis in Venezuela.
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