Tepui

From Free net encyclopedia

The Tepuis are table-like 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, and 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.

1 Origin of the Tepui
2 Flora and Fauna
3 Selected Tepuis
4 See also
5 References
6 External links

[edit]

Origin of the Tepui

Image:Mt Roraima in Venezuela 001.JPG

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 Tepui 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. The precipitous mountains tower over the rainforest by up to 1,000 meters. The surface of the mountains display various characteristics. On the plateaus of the mountains grow uninterrupted forests with a wide variety of orchid and Brocchinia species. Erosion and weathering has, over the course of millennia, formed peculiar rock formations and labyrinths.

[edit]

Flora and Fauna

Image:Roraima-Tepui Plateau.jpg The plateau of the mesas is completely isolated from the forest on the ground. On the one hand the altitude causes them to have a different climate from the ground forest, on the other the precipices are difficult to climb. This isolation has over millennia led to the presence of endemic flora and fauna. On the surfaces there is a temperate, cool climate with frequent rainstorms, while the bases 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 during rainstorms. 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.

The mesas, also known as 'islands above the rainforest', are a challenge for researchers, as they are home to a high number of species which have still not been identified. A few mesas 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.

A large number of mesas can be found in the Canaima National Park in Venezuela, which has been classified as a World Heritage Site by UNESCO.

[edit]

Selected Tepuis

Image:Roraima-Tepui Wand.jpg 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 Romaima. 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. The Kukenam Tempui 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. The Autanatepui stands 1,300 m above the forest floor. Inside the tepuis there are crevices of up to 400 m deep, named the Simas. It has been suggested that these holes were once huge caves whose roofs fell in.

Neblinatepui, also known as the Pico da Neblina, is the highest mesa.

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.

[edit]

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.

[edit]