MOSCOW, 2 Jun — RIA Novosti. , Russian scientists modeled the formation of craters formed in the permafrost as a result of methane emissions. The study is published in two papers in the journal of Geosciences.
In 2014, on the Yamal Peninsula near the Bovanenkovo gas field was discovered the first “Yamal crater” — a giant crater with a diameter of 40 meters with vertical walls. Since in the Arctic, geologists found several similar structures, but scientists still argue about their origin.
One of the main hypotheses — a methane explosion. The permafrost zone, which occupies two thirds of the territory of Russia, is a giant natural reservoir for this gas. In the conditions of warming in the Arctic region and the gradual destruction of permafrost methane in the deep, is released and escapes to the surface in the form of a powerful explosive output.
Skoltech Scientists together with colleagues from the Department of science and innovation Yamalo-Nenets Autonomous Okrug (YANAO) and Scientific centre for the study of Arctic region over the two years investigated one of the craters on the Yamal Peninsula. They managed not only to build a model of its formation, but also to determine the source of methane.
“the Craters in the Arctic — is a rare phenomenon that occurs, usually in inaccessible regions of the Arctic tundra. Swelling the surface, which precedes the appearance of the crater of gas emission, occurs quite rapidly, often within one-two years, and the rapid growth of the formed mound it is difficult to fix — are in press release the words of the head of the study, lead researcher of the Skoltech Center for hydrocarbon production Evgeny Chuvilin. — Almost all of the craters were discovered after their formation. There is only fragmentary evidence of local residents who said they heard the noise or saw the smoke and flames. It should also be borne in mind that craters formed quite quickly, just one-two years, turn into lakes, which will eventually difficult to distinguish from normal thermokarst lakes in the Arctic tundra”.
Scientists have studied the crater of gas emission in the floodplain of the river Ercot-Yakha, in the summer of 2017 was accidentally discovered by biologists studying the nesting Falcon. According to Chuvilin, Skoltech scientists are very lucky: they were able to get to a little-known Irkutskogo crater and explore it in the first year since the formation, because the next year he was already filled with water and became a lake. At the time of detection crater had a depth of 20 meters and the same width.
In December 2017, the researchers took samples of permafrost, ground ice and water from Irkutskwow crater, and later spent six months monitoring with drones. In samples of underground ice, scientists found the ratio of carbon isotopes typical for biogenic hydrocarbons. At the same time the amount of methane to the total volume of the homologues of ethane and propane pointed to the flow of gas from the deeper layers.
Under this lake, according to the authors, there were talik — phase antifreeze gas-saturated rocks, which after drying of the lake began to freeze from all sides, with the result that it created a strong tension, which subsequently led to a powerful explosion.
“the Formation of the crater of gas emission in permafrost is unexplored and virtually no process previously described, which represents the explosive ejection of a mixture of rocks, ice, water, and gases. Some researchers call this cryovolcanism explains Chuvilin. Such natural processes with the formation of large craters can pose a hazard to human life in the Arctic. This raises the need for their prediction based on the results of the study of the sources of gas, primarily methane, mechanisms of their accumulation in the upper horizons of permafrost and the conditions of occurrence of explosive gas emissions. Such emissions can contribute to the increase of greenhouse gases in the atmosphere.”.
Methane is a powerful greenhouse gas, and getting it into the atmosphere could accelerate global warming, scientists say. On the other hand, climate change will lead to more release of methane from the strata of permafrost.
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