Salzachöfen Gorge - Pass Lueg

Near Pass Lueg, the Salzach Valley takes on a strange shape. This is a textbook example of a breakthrough valley .

The transition from a wide valley south of Pass Lueg to the extremely narrow gorge at the Salzachöfen and then again a wide valley to the north is a combination of rock contrast, breakthrough valley and glacial deepening.

South of Pass Lueg, the Salzach flows in a relatively wide, U-shaped valley (Pongau section), which has been significantly widened and deepened by glaciation in softer or tectonically weakened rocks at the northern edge of the Hohe Tauern. During the ice ages, a thick Salzach glacier lay here, deepening and widening the valley floor by several hundred meters.

At Pass Lueg, the Salzach must pass between two hard limestone massifs: the Hagengebirge to the west and the Tennengebirge to the east ( Dachsteinkalk ). There, the river (and, earlier, the glacial meltwater) carved a breakthrough valley through the solid limestone, creating the Salzachöfen gorge : up to approximately 80 m deep, in places only a few meters wide, with gullies and deeply incised walls. In such a hard limestone barrier, the river cannot move laterally as it can in softer material, so a narrow, steep-sided gorge is created instead of a wide valley.

Immediately north of the gorge, the river enters the Salzburg–Hallein Basin and further into the Salzburger Becken, where softer flysch and molasse rocks lie and where glaciers have carved out significantly shallow troughs and basins. This foreland basin has been eroded by repeated glaciation to over 200–300 m below the present valley level and later filled with lake and river sediments; on the surface, this is visible as a wide, open valley through which the Salzach meanders.

Pascal Brackman