Dead Ice Kettle or Sinkhole?
What looks the same does not necessarily have the same cause. We are looking on circular depression structures on farm land. The movies were taken in northern Brandenburg near Angermünde (2023) and in North Lithuania in the Birzai region (2022).
The farmers are ploughing their fields and the tracks circle the depressions. What makes the differences of the identical looking depressions?
In North Brandenburg the landscape was formed during the last ice age. The depressions are the result of thawing ice in the subsurface after the glaciers retreated far to the north. The process is complete and the depressions are becoming shallower and will disappear in the near future.
The depressions in the Birzai region are the result of subrosion. The gypsum near the surface is being dissolved and more and more sinkholes are forming. The leaching process continues and the density of the sinkholes is increasing.
With sound mix from freesound.org under Attribution 4.0 License:
https://freesound.org/people/Erokia/s...
https://freesound.org/people/Erokia/s...
Thanks to Eroika!