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Many thought that Lake Cheko was an impact crater of a large explosion that occurred near the Tunguska Riva in Siberia, detected hundreds of miles away. However, Russian scientists found that Lake Cheko is at least 280-years-old, which means that the lake dates back hundreds of years before the Tunguska event. The so-called Tunguska event is still a mystery after 108 years. It’s the largest impact event on Earth in recorded history.
On the morning of 30 June 1908, a large fireball crossed the sky above the taiga over the Stony Tunguska River in Krasnoyarsk Krai in Siberia. A large explosion followed, which one could hear even in distant villages 1,200 kilometres (745 miles) away, and visible even in Britain. It flattened 2,000 square kilometres (770 square miles) of forest. During the following days, observed noticed strange phenomena in the skies above Europe, such as silvery glowing clouds, colourful sunsets, and a strange luminescence in the night. Soon, Russian newspapers reported that it was a meteorite impact, whilst foreign newspapers speculated on various scenarios from a volcanic eruption to a UFO accident. However, the unpredictable political situation in Russia at that time prevented further investigations.
After 13 years, the first research expedition led by Russian mineralogist Leonid Kulik visited the Tunguska site. Despite exploring the entire area, they didn’t discover a single great crater or meteoritic material. To explain this fact Kulik suggested that some natural extraterrestrial solid exploded in the Earth’s atmosphere. Over time, scientists proposed many other theories, some quite unusual, to explain the apparent lack of craters and missing extraterrestrial matter. In 2007, a research team of the University of Bologna in Italia led by Luca Gasperini proposed that a small lake in the region, Lake Cheko, might have been the impact crater. They based their assumptions on the fact that the lake is unusually deep for the region and its shape looks like a crater. Moreover, there’s no record of the lake existing before 1908. Gasperini’s evidence is controversial, as seen in one published answer to this research.
In July 2016, a team of Russian researchers from Krasnoyarsk and Novosibirsk explored Lake Cheko again to estimate its real age. Before the 20th century, there were only poor maps of the region so the lake might have existed before 1908, they presumed. One can estimate the age of a lake by assessing its bottom sediments. Last year, the scientists obtained a core sample of bottom sediments from the deepest trench of Lake Cheko for geochemical and biochemical analysis. Recently, their colleagues from the Institute of Geology and Mineralogy, Siberian Branch of The Russian Academy of Sciences (RAN) completed radioscopic analysis of the core samples.
The study showed that the deepest sample is about 280 years old, which means that the lake is probably even older because the researchers didn’t manage to get samples from the very bottom. Nevertheless, this proves that Lake Cheko is older than the Tunguska event and isn’t an impact crater of a supposed Tunguska meteorite impact. According to Denis Rogozin, a senior research worker at Krasnoyarsk Research Centre, Siberian Branch of the RAN, the results of the study will appear in a peer-reviewed scientific journal on 30 July 2017, the anniversary of the Tunguska event. The results of the Russian scientists’ research left academia without a clue; it meant that they might not find any evidence that the Tunguska event actually was a meteorite impact. It made the Tunguska event really mysterious again.
18 January 2017
Sputnik International
https://sputniknews.com/science/201701181049718416-tunguska-event-lake-cheko/
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