Subsidence cauldrons persist in thick glaciers where there is much geothermal heat beneath. The outflow appears in rivers, sometimes in glacial outburst floods. They can be from a few tens of metres in diameter up to 2-3 km. Among the best known are the Skaftá cauldrons.
Found at: Mýrdalsjökull, Austur-Reykjadalir, Þórðarhyrna, Grímsvötn, Pálsfjall, Skaftárkatlar, Kverkfjöll
Holes and caves
Holes and caves melt in thin glaciers and snowfields. Well-known examples are in Torfajökull, Hrafntinnusker, Kaldaklofsjökull and Kverkfjöll.
Found at: Austur-Reykjadalir, Ljósártungur, Kverkfjöll