9 months ago
?? at the look of the near landscape features, i believe this maybe a repetitive cycle.
9 months ago
@twoquarters training
In the work of the Volga German Joseph Christian Hamel "Description of the Tula Arms Factory in historical and technical terms" about 200 years ago is stated...
(*) Pokrovsky, a former teacher of Tula Gymnasium, wrote about these gaps in great detail as a natural landmark of this region, trying to explain the origin of these gaps by underground rivers washing out the lower layers of the earth. - These pits were formed simply by the fact that in those places where the ore layer was excavated from below, the land subsequently settled from above, and that ore in these places was excavated in very distant times, it is clear from the fact that the current inhabitants of Dedilov have no idea about the true cause of the gaps.

Look on the lakes at the left of the current gap. Probably these were previous gaps. I think after 5 years current gap will became lake too (after snowy winters)