With respect to morphology and dimensions the mapped buried valleys are comparable to open tunnel valleys found in the present-day Danish landscape. Most likely, they were formed as tunnel valleys and subsequently buried by younger sediments. Subglacial meltwater erosion is believed to have caused most of the erosion, whereas direct glacial erosion may have contributed to the formation of the widest valleys. The presence of multiple valley generations shows that glaciers repeatedly transgressed the area during the Pleistocene. Tunnel valleys have a pronounced tendency to be re-used during repeated cycles of glacial erosion, which produces the cut-and-fill structures.

The buried tunnel valleys are isolated features which are not interconnected in anastomosing systems. It is unclear whether all valleys in each generation were formed simultaneously or if the individual valleys were formed separately. It is however evident, that many tunnel valleys became ice-filled by creeping ice following the erosion of the bed. Steady subglacial meltwater flow or recurring meltwater releases may continuously have eroded deeper into the substratum followed by ice creep closure of the meltwater channels during periods of decreasing meltwater pressure.

It is difficult to determine the ages of the buried valleys. The infill sediments can be dated in some cases, but this is not necessarily the time of valley erosion. However, based on the time gap between the age of the eroded sediments and the age of the infill sediments, some of the buried valleys can be shown to have formed during the Weichselian, the Saalian and the Elsterian glacial stages. Some of the valleys were probably formed during older glacial stages.