More than a decade after the discovery of enigmatic craters in the permafrost of Western Siberia, researchers continue to explore their origins. A team of geoscientists from the University of Oslo, led by Helge Hellevang, has proposed a new model that may clarify why these craters predominantly occur on the Yamal and Gydan peninsulas, while remaining absent in other Arctic permafrost regions.
The first of these craters was identified in the Yamal Peninsula in 2014. Measuring approximately 30 meters (98.4 feet) in diameter and over 50 meters deep, the crater was surrounded by ejecta, suggesting an explosive genesis. The vertical walls of these craters resemble those made by machinery, adding to the mystery surrounding their formation.
New Theories on Crater Formation
Hellevang and his team identify a build-up of pressurized methane as a primary factor in the creation of these holes, now referred to as gas emission craters (GECs). While earlier theories suggested that internal permafrost processes were solely responsible for the eruptions, the latest findings challenge this assumption.
In their study, the researchers argue, “If permafrost-internal processes, triggered by climate change, were responsible for the eruptions, one would expect that GECs would also form elsewhere in areas of permafrost containing gas hydrates, ground ice, or cryopegs. This is not the case.” They emphasize that the volume of gas-filled cavities necessary to account for the formation of GECs and the associated ejecta could not arise from permafrost alone.
Instead, the research indicates that heat and natural gas from deep beneath the permafrost, particularly from fault systems in the bedrock below the Yamal and Gydan peninsulas, are essential for generating the force needed for these subterranean explosions. This is significant, as these peninsulas are situated above one of the largest natural gas reserves in the world.
The Role of Climate Change
While the new model provides a compelling explanation for the craters, it still acknowledges the influence of climate change. The researchers suggest that climatic shifts may contribute to exposing these craters. As lakes expand and weaken the permafrost, they create a thinner layer for gas to escape through, facilitating the explosive events.
Although this model presents a promising avenue for understanding the origins of the craters, further research is necessary to validate these findings against real-world measurements. Only through continued investigation will scientists uncover the full story behind these mysterious formations.
This research was published in the journal Science of the Total Environment, adding to the growing body of knowledge regarding the interactions between geology, climate, and the unique phenomena observed in Siberia.
