The Partnach Gorge is a deep gorge that has been incised by a mountain stream, the Partnach, in the Reintal valley near the south German town of Garmisch-Partenkirchen. The gorge is 702 metres long and, in places, over 80 metres deep. It was designated a natural monument in 1912.
In the Triassic, about 240 million years ago, on the bed of a shallow sea, dark grey, relatively hard layers of Alpine muschelkalk, so-called Wurstelkalk, were laid down in the area of the present day Partnach Gorge. On the bead-like strata of this rock the traces of the burrowing and feeding of marine animals can still be seen. Importantly, about 5 million years later, softer marls were deposited in the same marine basin, which today are known as Partnach Strata (Partnach-schichten).
In the course of the subsequent Alpine mountain folding the so-called Warnberg Saddle (Warnberger Sattel) was formed from these rock strata. The erosion force of the Partnach stream, which was fed from the Schneeferner glacier on the Zugspitzplatt plateau was great enough to carry away quickly the softer layers, to keep pace with the continued uplifting of the terrain and thus to cut into the hard Alpine muschelkalk as well. Today the river forms the typically narrow valley shape of a gorge (Klamm) in the area of the muschelkalk rocks, whilst the areas of softer Partnach strata to the north and south have a wider valley cross-section.