Mount Roraima

Roraima Tepui

The steep rock wall of the Roraima Tepui

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The Roraima Tepui ( from Pemón roroi " turquoise blue", " fertile ", ma "large" ), and Mount Roraima Cerro Roraima or, is a 2,810 m high tepui in the border triangle between Venezuela, Brazil and Guyana.

He is the namesake of the Brazilian state of Roraima. Until 1962 the name was Território do Rio Branco region, but always it came to misdirection of letters and settlers who were trying in this region, but finally arrived in the former capital of Rio Branco Acre Territory.

Location and data

In the Gran Sabana are 115 tepuis ( table mountains ), of which the Roraima Tepui and Auyán - tepui are the best known. The largest expansion of the Roraima plateau is about 15 km and rises up to 700 meters above the tropical rain forest. To the west of Mt Roraima is the Zwillingstepui Kukenam.

The landscape on the high table is a rock maze with many gorges - sometimes several hundred meters deep - and no plateau, as was formerly supposed. The sandstone is 95 percent pure quartz and is crisscrossed by many hydrothermal quartz veins. Therefore, one can find Zusammenschwemmungen from nothing but small quartz crystals and also whole crystal specimens originating from these transitions on the surface again and again. The area is part of a National Park, so the entrainment of any minerals from Roraima is prohibited.

Fauna and Flora

On the plateau of the tepuis grow mainly lichens, grasses, Stegolepis guianensis, Orectanthe sceptrum and various orchids. However, the nutrient-poor sandstone soil is also ideal for carnivorous plants such as marsh pitchers, Reuse traps and sundews. The fauna consists of insects, birds, amphibians (eg Oreophrynella quelchii ) and smaller reptiles ( snakes, lizards ) and mammals ( mice). On the Roraima about 80 percent of all organisms are endemic, that is, there is a unique, occurring only on the Tepui animal and plant world as it is found nowhere else in the world. One reason is that several hundred meters high cliff, which represents an insurmountable barrier, another the different climate that leads to thermal insulation over the rainforest. On the floor a moist, tropical climate (~ 30 ° C), on the plateau prevails, however, a rather moderate ( ~ 10 ° C ) with different weather conditions.

Formation

For a long time it was impossible dating of the emergence of the Roraima Tepui. The sandstone contains no fossils, which would help determine the age. In the 1980s it was discovered Special stone inclusions that came from deep underground and were transported through cracks in the sandstone to the top where the glutförmige ground froze. This rock contains radioactive elements such as uranium, which decays after a few billion years to lead. To determine the time of the setting, you have to check how much uranium has become the rock to lead. The sandstone inclusions yielded a date of 1.8 billion years. However, as this only indicates when the rock solidified, the tepui sandstone must be considerably older itself. Geologists have estimated the origin of the tepui sandstone 2 billion years ago. The division of the Tepuisandsteines in Roraima and Kukenam probably happened 160 million years ago, when the supercontinent Gondwana broke apart and South America drifted westward. Probably a great earthquake was the cause of this division.

History

The local Indians never attempted to climb Roraima Tepui, and also the discoverer of the 18th and beginning of the 19th century could only speculate what is on the high plateau. It was thought extinct species ( even dinosaurs ) that would have survived there. Several naturalists, geographers, botanists and anthropologists explored the area around Roraima, as Richard and Robert Schomburgk ( 1838-1844 ), Ernst Ule (1909 /10) and Theodor Koch - Grünberg ( 1911). Im Thurn in 1884 succeeded the British explorer Everard the first ascent of Mount Roraima. He found only herbs and shrubs. End of the 19th century there was a conflict when Britain wanted to annex of British Guiana from the region of the tepuis, since you (eg diamonds) found in the area natural resources. However, they retreated back to the request of U.S. President Grover Cleveland. 1899 an international tribunal in Paris was convened to resolve the border dispute. Here it was decided that the majority of the area (including Roraima ) belonged to British Guiana. As the access to this day only Venezuelan side is possible, the British the area but could not open up.

In 2010, it succeeded in an expedition with Stefan Glowacz with the first ascent of the route "Behind the Rainbow" to put ( X / X - ), a route through the overhanging cliffs of the mountain. About the expedition was in 2013, the film Raiders of the moment.

Reports of the famous South American explorer Sir Robert Hermann Schomburgk inspired the English country doctor Arthur Conan Doyle to a novel The Lost World (1912 ) about the discovery of a living prehistoric world full of dinosaurs and prehistoric plants. Arthur Conan Doyle never mentions in his book the name of Roraima. In the novel, the Table Mountain is unclimbable. Only by a trick succeeds the novel's characters to come to the plateau by an offshore rock pinnacle climb and cross the gorge with a felled tree. This pinnacle is also available in the reality, but it is more than just a tree length from the plateau.