Giant sinkholes are abnormal geological structures that appear whenever a landmass drops down from its original level. The phenomenon could occur not just in the cities and forests, but also in frozen bodies in other parts of the globe.
A new study discovered that a group of massive sinkholes is increasing in the Arctic seafloor. According to the authors, the submersions were caused by the melting of permafrost underneath the ice sheet.
Arctic's Melting Permafrost and Sinkholes
The thawing of these frozen grounds induced the disturbance beneath multiple regions and pulled the ice structures down from their altitudes.
The melting of permafrost has been a topic for numerous studies. Based on most investigations, permafrosts tend to melt because of the ever-surging global warming.
Climate change might have been the culprit of the Arctic sinkholes, but this case offered a different suspect. The experts found out that the heat pushing the frozen grounds displaced the heat not related to climate but the groundwater systems.
The Canadian Beaufort Sea, where the giant sinkholes appeared, had permafrosts already submerged about 12,000 years ago. The Arctic sheet already experienced this event during the last ice age, a period where abundant glaciers covered the northern hemisphere.
The frozen seafloor remained in its state until now, when scientists detected unusual geological movements in the area. The new study was quite challenging for the authors, as the locations are considered among the absurdly remote parts of the Arctic. Thanks to the innovation in the transport industry, these areas are already accessible to people.
The examination of the Arctic sinkholes in the Canadian Beaufort Sea was made possible through the help of modern technological mediums such as a highly-accurate sonar device equipped to the ship of the researchers and an autonomous underwater vehicle or AUV that could capture quality underwater surveys.
Disturbance in Seafloor of Canadian Beaufort Sea
Monterey Bay Aquarium Research Institute (MBARI) geology expert and lead author of the study Charles Paull explained that despite what we know about the abnormal shifts occurring in the Arctic sheet, this is the first time that technology brought us a glimpse of the changes taking place offshore, too.
But even if it is established that most of the underground sinkholes appear as a result of long-term glacial-interglacial climate cycles, it can not be denied that the Arctic is the top region that is warming the fastest than any parts of the globe, Paul continued.
The observations of the sinkholes began back in 2010, back when the most evident changes were found at the shelf edge and slope at the Canadian Beaufort Sea. From the shore of this area, the researchers noticed rough terrain on the seafloor 180 kilometers far.
This same spot is the mark of the last ice age during the Pleistocene period. To learn more about the region, the team followed up with three separate surveys over the next few years.
AUV and ship sonar captures in 2013, 2017, and 2019 revealed steep emergence and irregular depressions. Based on the measurements, the largest sinkhole they discovered scaled to a whopping 225 meters in length, 312 meters in width, and 92 feet in depth.
The study was published in the journal Proceedings of the National Academy of Sciences, titled "Rapid seafloor changes associated with the degradation of Arctic submarine permafrost."
Read also: Endurance Shipwreck: How Shackleton's Vessel Was Rediscovered Underneath Antarctica's Ice Sheets
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