Deep in the rainforest of Venezuela, a country in northern South America, there are some mysterious mountains. These mountains are completely flat-topped and surrounded by almost completely vertical cliffs. The entire mountain is like a raised table, isolated from the surrounding environment.
△Roraimat Puis, the source of inspiration for Conan Doyle's "The Lost World"
Some flat-tops are very high, and the height of the cliffs can exceed the surrounding forest by 1,000 meters. These mountains are surrounded by clouds and mist for most of the year, and they look like they are in a rain forest.island in the skySame.
Some flat-tops are also very large, with the largest area reaching 700 square kilometers, equivalent to a medium-sized city in China, with clear pools, streams, and waterfalls - the highest waterfall in the world comes from one of the flat-tops.
The indigenous people living there——PemonThese mountains are called "tepui)", meaning "pantheon"Because of the vertical cliffs surrounding these mountains, it was difficult for the Pemon people to reach them, so they left behind many beautiful or terrifying legends.
△Angel Falls is the highest waterfall in the world, coming from Mount Oyantepuy
Now, geologists continue to use the name of the Pemon people and call this unique landformTepuy, they only appear in a few specific areas of South America.
Most of them are in the Greater Savannah region in southeastern Venezuela, which borders Guyana and Brazil. There are 115 such Tepuis mountains, with a total flat-top area of 5,000 square kilometers!
So the interesting question is, how come there are such strange mountains? What kind of creatures live on them?
△The area where Mount Tepui is concentrated
How was Mount Tepui formed?
The area where Mount Tepui is located is a remnant of the ancient supercontinent Gondwana, and may be a desert area close to the interior.
During the ancient continental period, thick layers of sandstone were deposited here, and due to weathering, most of the minerals in the sandstone were decomposed, leaving only harder quartz grains.
These quartz particles were eventually transported by wind and water to relatively low-lying areas. Over time, the quartz sediments were buried underground. Under pressure and special chemical reactions, they gradually consolidated into thousands of meters thick layers.Extra large quartz sandstone.
Later, crustal movements lifted the quartz sandstone buried underground. Finally, due to erosion, the more fragile rocks around the quartz sandstone gradually disappeared, leaving Tepui Mountains in the area.
A Tepui mountain is a large piece of quartz sandstone, with a quartz content of up to 98%, was formed 1.8 billion years ago, soThese mountains are also among the oldest geological formations in South America.
After the quartz sandstone formed, it was covered by other types of rocks around and above it for the next 1.5 billion years.
About 300 million years ago, the area began to uplift and erode, but because quartz is so hard and resistant to erosion, only it remains.
About 180 million years ago, the rocks and other sediments surrounding these quartz sandstones were eroded away, and eventually the quartz sandstone was exposed and became today's Mount Tepui.
You may not understand why these mountains have flat tops (because I didn’t understand them at first either)?
There is a geological law that determines this property, known as "original horizontality"" means that the sedimentary layer will tend to be horizontal or close to horizontal when deposited, and the same is true for other sediments.
Simply put, when the quartz grains were first deposited, they themselves were horizontal, and the resulting rocks remained horizontal.
lost world
Although Mount Tepui is just a huge piece of quartz sandstone, it did not stop the conquest of life on earth. It is a truly lost world.
Many Tepui mountains have extremely high cliffs, making it difficult for creatures in the forest below to overcome and creatures above to escape, forming isolated ecological islands.
Many people call Mount Tepui the highest mountain on the mainland.Galapagos Islands, the animals and plants above are isolated from the world and evolve independently.
Although Mount Tepui is named after "the Temple of the Gods", the land there is very barren.
The quartz sandstone ground also gradually weathered, eroded, and became rugged, which meant that no fertile humus layer formed there, so the plants and animals that lived on it were adapted to unstable resources.
Among them, carnivorous plants are the most common, mainly sundews and pitcher plants. The main reason why plants have evolved to be "predatory" is that the land where they grow cannot provide enough nutrients.
△The sundew can catch food through the mucus on it
△Nepenthes
There is also a wide variety of orchids and bromeliads that have adapted to the cliff environment.
The animals are mainly insects and frogs. Some Tepui mountains also have snakes, lizards and other predators. They can survive with fewer resources.
It is worth mentioning thatSome of the animals on these islands aren't completely isolated from the rest of the world. Research in 2012 found that after the formation of these Tepui mountains, tree frogs from different mountains had genetic exchanges with each other.
The researchers searched for four species of tree frogs on different Tepui mountains and analyzed their DNA to determine whether the species had come into contact over the past 70 million years.
It turns out that four species of tree frogs from different Tepui Mountains had a common ancestor 5.3 million years ago, which means that the towering cliffs of Tepui Mountain did not hinder the migration of these tree frogs.
Because these Tepuis mountains are in the rainforest, the most indispensable thing there is precipitation, which makes almost every Tepuis mountain have crystal clear pools and streams, and even waterfalls on the cliffs.
This environment attracted some nectar-sucking resident birds. I wonder if the birds carried tree frog eggs for dispersal, which eventually allowed them to have genetic exchanges with each other.
In any case, there is still much to explore about the unique geographical structure and biomes of Mount Tepui.