These news are from Tarsoly Péter, member of MKBT Vulkánszpeleológiai Kollektíva
On the 24. november 2015 the major of Pázmánd told us, that a hole opened on a corn field, after the ground collapsed under an agricultural vehicle. After we visited the site, it was clear that the hole opened at least one year ago.
The hole is around 10 meters deep, and has 1 meter radius at the opening.
The hole was formated by suffosion in the loess sediment. Probably subsoil water and surface precipitation also helped to form it. By digging about 1 m3 soil it would be possible to track the waters way down, but probably it would be difficult to reach the solid andesite stone layer. Geological surveys nerby show that the vulcanic andesite layer starts in 20 meters underground. According to resarch work by Földváry Aladár in 1956, the CaCO3 (limestone) content of the loess in this field is 32-37%, the density is 2.7991 – 2.8156 g/cm3. Thisi data partically explains the properties of this hole.
Because of the loose structure of the walls, it is only possible move with rope technique. For fixing the rope we used our parking car nearby.
Thanks for Tarsoly Péter for the pictures and information!
Non-karstic cave database of Hungary is found here : nonkarstic.geo.info.hu