YEKATERINBURG, November 12. /TASS/. Russian researchers for the first time have reached the bottom of the strange large crater on the Yamal Peninsula, northwest Siberia, the press service of the regional government told TASS.
Scientists went on the third expedition to the crater on November 10. They managed to take samples of the ground and ice.
It is located four kilometers away from a gas pipeline and at a considerable distance from gas fields. Human activities could not cause the cave-in, the press service said.
During the summer, scientists could not examine the bottom because ground continued to collapse in the crater.
On the last expedition, researchers reached the depth of 200 metres despite the strong wind with gusts of up to 20 m.sec.
Specialists will study the chemical composition of the samples.
Scientists say the crater may be filled with water in a few years and become a small lake, such as many others in Yamal. It is proved that some of them appeared in such cave-ins. But scientists still do not know definitely how the craters were formed, the press service said.
The next expedition is planned for April 2015.
The chairman of the board of the Tyumen Scientific Society of the Siberian branch of the Russian Academy of Sciences, academician Vladimir Melnikov, said the craters were formed in Yamal in 2012 and 2013 as a result of the climate warming.
Frozen ground began to melt. At some places, it became less thick, and shale gas came out through it. Shale gas is found along the entire sub-Arctic shelf. Supposedly, it caused the formation of the crater, Melnikov said.