30 million years ago a meteorite 2.5 kilometers in diameter fell in the savannas of Vichada, a region to the east of Colombia. The impact generated a huge crater in which, little by little, a jungle grew that today is home to 90 indigenous families of the semi-nomadic Sikuani tribe and is home to at least 1,500 species of animals and about 1,100 species of plants, according to studies. of the Humboldt Institute, the research center in biodiversity and ecosystems most important in Colombia.
Luis Santiago Castillo , a biologist at the Institute and leader of the project that seeks to study and protect the culture and nature of the area, tells by phone that the old hole caused by a celestial body measures 50 kilometers in diameter and combines fauna and flora of the savannas with that of the tropical forests of the Amazon. “The Aliwa forest, as the indigenous people call it, contains biodiversity typical of the two ecosystems. This crater is the hinge between the plain and the jungle ”, says Castillo.
Since 2018, scientists have made several expeditions to the place in order to dialogue with native communities and begin to explore a territory that has not yet been studied by western science. These field trips, added to projections made with information from databases of the region and testimonies of the inhabitants, reveal that in this jungle there could be a total of 2,677 species of plants and animals, a very high figure compared to the biodiversity of the area surrounding the old crater.
Hernando García Martínez, director of the Humboldt Institute, insists that due to their location and origin these forests must have unique biological characteristics. The jungles of Aliwa are "a treasure of Colombian biodiversity" in which possibly 144 species of butterflies, 331 of fish, 64 of amphibians, 163 of reptiles, 684 of birds and 183 of mammals coexist. It is even estimated that six endemic species and 33 species of flora and fauna in danger of extinction inhabit the crater, including the Orinoco crocodile, the morrocoy tortoise, the spider monkey, the giant armadillo, the pink dolphin, the jaguar and the tree. de Castaña.
In the project, called Safeguarding the biocultural heritage in the ancestral territory of the Aliwa indigenous community , The organizations WCS-Colombia, Nature and Culture International (NCI), Global Wildlife Conservation (GWC) and the Traditional Indigenous Authorities also participate. "The objective of this alliance is to generate strategies for the protection, defense and ancestral conservation of the Aliwa jungles and its biocultural heritage, all from a dialogue between traditional knowledge and science," explains Martínez.
Sergio Andrés Torrado Pérez , Master of Science and Geophysics from the National University of Colombia, was one of the researchers who in 2020 was able to confirm that the Aliwa jungle had indeed emerged from a meteorite crater . From his home in Bogotá, Torrado explains by phone that his research began in 2016 with the purpose of confirming or rejecting the hypothesis of an Argentine scientist who in 2004 said that an asteroid had fallen in the area and that is why it had such a different biodiversity to the rest of the region.
Torrado says that when he and his co-workers arrived in the area they were puzzled because the crater was not visible to the naked eye. “This crater is characterized by being a hidden impact structure. It is covered by more recent sediment deposits and by very dense vegetation. This makes it impossible to distinguish. " The scientists had to apply a geological model to see how the structures in the different layers within the earth behave and combine it with satellite images that, according to Torrado, were beginning to coincide with the meteorite hypothesis. "The observations show a structure with two rings that show a concentric and almost perfectly circular curvature in a totally flat terrain," said Torrado at the time of the discovery.
However, the irrefutable proof of the impact of the celestial body is so far that on the surface were strange rocks for the region similar to those of other meteorites. "We analyzed stones from one to three meters high that, due to the plain that characterizes the Vichada savannas, should not be found there," says Torrado. And he adds: "In the study of these rocks there is mineralogical evidence, deformed materials and specific minerals that are generated by high temperatures and high pressures, which helped us to determine that it was a meteorite crater."
The researcher and professor of Geology Orlando Hernández affirms in a scientific article that the Vichada crater is "similar to the one found in Sudbury, Ontario, Canada , the second largest impact crater on Earth, after the Vredefort crater in South Africa" . According to the researchers, the impact of the meteorite may have generated microenvironments that favor the proliferation of fauna and vegetation. “That land is special. In areas where there have been asteroid impacts worldwide, there is usually enrichment of certain metals and minerals that make many trees grow. In this case, we found mounds of earth that have a high content of ferromagnetic minerals, ”says Torrado. This could be one of the reasons why the Aliwa jungle, located in the middle of the savannas and grasslands of Vichada, is home to so much Amazonian biodiversity.
Torrado concludes that it is an asteroid impact crater. "We have the geological and geophysical evidence, and we are in the process of formalizing the crater so that it is recognized by the Planetary Society, an NGO dedicated to promoting the space exploration of the solar system and the scientific dissemination of planetary sciences and astronomy throughout the world. world. ”
Another clue that this majestic jungle grew inside a meteorite crater is the behavior of the Vichada River, which surrounds part of the old hole. According to the biologist Santiago Castillo, the course of the rivers in the region has a constant trajectory. "Normally the rivers go from south west to northeast, diagonally to flow into the great Orinoco river, one of the largest in the world, but when the Vichada river approaches the crater it loops to the south quite evident", says Castillo . The researcher explains that it is most likely that when it fell, the impact of the meteorite had raised the ground and deviated the normal path of the river.
In addition to studying the biodiversity of the ancient crater, the Humboldt Institute project seeks to strengthen the intake processes decision-making by the community to guarantee the control and protection of the territory. The biologist Santiago Castillo warns that the area has had complexities of war: "there are coca crops around and a river that comes out of the jungle has been used as a channel for deforestation."
Paula Ungar, researcher of Territorial Management of the Institute, He explains that in the ancestral Sikuani territory, “legal and illegal interests come together that are manifested in various forms of colonization: large cattle farms, small settlers who deforest and the territorial dynamics associated with the armed conflict and drug crops”. This situation has generated tensions between the indigenous people and the armed groups that endanger the territory and make it difficult to study. The researchers agree that another of the objectives of the work is to strengthen the indigenous guard against the threats of extractive activities such as hunting, deforestation and the trafficking of illegal substances.
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