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Mount Roraima is a "Tepuy" (mountain in the indigenous Pemón language); a horizontal-topped mountain located in one of the oldest geological formations on the planet, about 3.6 billion years old.
Its highest point is called “Maverick”, which reaches 2,810 meters above sea level and is so called because from afar (during the walk) you can see its silhouette identical to that of this car. Some even they call it "The Car." Roraima is the geographical landmark that demarcates the borders between Venezuela, Brazil and Guyana.
This Precambrian mass is divided between Venezuela (85%); Guyana (10%) and Brazil (5%). This place, revered by the Pemón indigenous people; It is an allegory of the genesis of humanity, the cradle of rivers and rock formations that defy the imagination. Visiting this wonder of nature is like entering a prehistoric world; a world "lost in time", where its endemic biology and its caves remind us how small we are in the world compared to these ancient monuments, witnesses of the formation of our planet.
Contents:
Geology
Geomorphology of a Tepuy
Flora
Fauna
GEOLOGY
The Geological Formation of Roraima was already ancient when the two continents: South America and Africa were connected as part of the supercontinent called "Gondwana".
From measurements of datable igneous diabase intrusions on tepuis such as Mount Roraima and others, geologists were able to determine that the sand deposited here was the result of an eroded mountain range, spread by rain and wind over the Guiana Shield, 1.8 billion years ago.
The wind erosion of the past, as well as the surface weathering that acted on the tops of the tepuis, now allows us to see how the layers of sand and volcanic ash sediments were deposited at the bottom of some lakes (Ripple Marks) and deltas that were formed in the Proterozoic; that is, before complex organisms appeared in the seas.
There is evidence that there has been no life in these formations, because no fossils have been found trapped between these strata. These layers of sediment gave rise to the layers of sandstone and jasper that make up the tepuis and which accumulated over some 200 million years, reaching a thickness that would be around 7,000 meters, but which now rises to between 700 and 1,500 meters. The Guyana Shield is formed by the igneous rock below. These Precambrian giants are the product of erosion over billions of years, with sandstone strata that have not undergone tectonic deformation and have undergone a geological process called isostasy, which explains why they are so tall.
Our guides are ready to take you to this Lost World and explain to you about this topic and many more of these natural monuments.
Mysterious rock formations
"Turtle" Stone, is a Yardang or wind-eroded rock
Top Table mountain Roraima
Perfectly horizontal sedimentary strata (layers)
Existence of wavy marks, evidence of ancient lake bottoms (Ripple Marks)
Kettles are holes produced by mechanical erosion (quartz) and known as Jacuzzis.
GEOMORPHOLOGY OF A TEPUY
A tepui is an elevation that reaches almost 3 kilometers in height, which is generally shaped like a table; it is made up of sandstone rock, with steep walls, with horizontal strata whose formation is one of the oldest in the world and with endemic biology. It is not a mountain, since it was not formed by orogenic processes; it is formed by erosion.
GEOMORPHOLOGICAL ELEMENTS OF A TEPUY:
1. Foothills (alluvial fans)
2. Base of the tepui
3. Steep walls
4. Edge zone
5. Surface of the Tepuy
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Stegolepis guianensis
Brochinnia tatei
Bonnetia roraimae
Beffaria imthurmi
Epidendrum secundum
Unidentified fern
FLORA
Roraima's summit plants cling precariously to life in deep cracks and crevices in the eroded rock surface; that is to say, there the little land there is can escape being washed away by heavy rains.
In the exposed areas, small cushions of endemic plants are piled up, resembling miniature Japanese gardens. There are so many beautiful and attractive flowering plants: almost all are exclusive to the tepuis, and more than half are known only from Roraima.
The summit of Roraima is a difficult environment for any living organism. The bedrock has a low mineral content, so the soils are poor in nutrients (especially phosphorus, calcium and nitrogen). Highly acidic organic peat, consisting mainly of decaying matter, rests directly on the bedrock of the tepui summit.
Rainwater quickly leaches out any nutrients, and floods continually erode soils. Some plants had to find a way to supplement their diet, capturing and digesting small animal "carnivorous plants"; most had to develop strategies to combat water loss and effectively anchor themselves in an inadequate substrate.
Animals must survive in an environment with limited food supplies and deal with extremes of radiation and temperature.
In the photos some specimens of the endemic flora found in the tepuis. In the photos, examples of the endemic flora found in the tepuis.
FAUNA
The explorer Im Thurn had not reported any animal life on the summit of Mount Roraima, but deep within the dense clumps of vegetation, small mammals dig burrows and smaller creatures forage for food. Among the bushes, almost voiceless birds jump silently. In this world of fog and rain, there is little or no insect activity, but with a few moments of sunshine, black butterflies like Protopedaliodes kukenani begin to flutter and large black dragonflies return, flying from one side to the other along ravines in search of prey. There are black tarantula spiders, black centipedes, and black insects of all kinds.
Melanism. Many animals are melanistic, dark brown to black; providing them protection against ultraviolet radiation, reducing water loss through evaporation and providing camouflage against the dark surface of the rock.
Amphibians. McConnell and Quelch, in 1894, made some interesting discoveries, among them a curious black frog, Oreophrynella, a genus endemic to the tepuis. Oreophrynella is an ancient species that has preserved its primitive characteristics because the tepui environment has not forced it to evolve radically. It is more closely related to frogs found in Africa than in South America, suggesting that its origins can be traced back to Gondwanaland.
Protopedaliodes kukenani
Campilopterus hyperithrus
Nasua nasua
Oreophrynella quelchii
Hydrolutos breweri
Steatornis caripensis