Studying the lake near the epicenter of the mysterious explosion 113 years ago

Russian researchers plan to dive about 30 meters deep to explore Lake Cheko, which is believed to be the impact crater of a meteorite.

Russian scientists will visit the remote Tunguska nature reserve in Krasnoyarsk, Central Siberia, at the end of February, according to the Siberian Times. The research team consists of 4 members who are licensed to dive below 30m. This is the first study conducted at such depths at Lake Cheko, Tunguska. The expedition will start a long-term research cycle, according to Evgenia Karnoukhova, an expert at the Tunguska reserve.

Lake Cheko in Siberia, Russia.

"Lake Cheko is 54m deep. The team aimed to understand the thickness of the sediment at the bottom of the lake and collect primitive samples. The data they collected will be analyzed and sent to geologists. We not to mention finding any celestial bodies at this stage," Evgenia said.

The Tunguska explosion of 1908 is still controversial in the scientific world. The event flattened 2,150 square kilometers of land with about 80 million trees. Several witnesses said they saw a bright ball of fire moving across the sky.

In 1927, Russian mineralogist Leonid Kulik led the first Russian expedition to investigate the Tunguska incident. However, the expedition also found no craters of asteroids or alien matter.

In 2012, a team from the University of Bologna, Italy, led by expert Luca Gasperini suggested that Lake Cheko with a diameter of 500 m and a bowl-like shape was an impact crater. This lake is located about 8 km from the hypothetical epicenter. Before that, it was not marked on the map. Seismic measurements at the bottom of the lake show that sediment has accumulated over about a century, and the lake's depth is also greater than is usual in this area.

The team concludes that there is dense rock material at the bottom of the lake and the sediment is the remnants of an exploding meteorite. They report that seismic and magnetic reflectance data reveals an anomaly near the center of the lake, less than 10 m below the lake bed. This anomaly is consistent with a buried rock object and supports the hypothesis that Cheko is a lake formed from an impact crater.

However, in 2017, a group of scientists from Krasnoyarsk and Novosibirsk, Russia, opposed this theory. They believe that the area above has not been fully mapped, so it is not strange that Lake Cheko does not appear in old maps.

The expert team assessed the date by studying lake bottom sediments, conducting geochemical and biochemical analyses. Their colleagues from the Institute of Geology and Mineralogy of the Siberian Branch of the Russian Academy of Sciences (RAS) completed radiological analysis of the drill core samples.

The deepest sample they obtained is about 280 years old. As such, Lake Cheko appears to be geologically young, but not young enough to be an impact crater during the Tunguska event. In addition, the Tunguska reserve also contains other lakes that are relatively round and deep like Lake Cheko and may have the same geological origin.