THE HOELLENTAL MUSEUM (DISTRICT GARMISCH-PARTENKIRCHEN, S-BAVARIA, GERMANY)

The Hoellental - a steep alpine valley measuring 8km in its longitudinal direction - is present in the NW-part of the Wetterstein Mountains. In the lower part of this valley, a deep stepped gorge (Hoellentalklamm) - at the bottom only a few meters narrow - accomodates the unbalanced passage between a high-lying valley (Hoellentalanger) and the erosion base (Loisach Valley). The gorge was registered as geosite by the Bavarian Geological Survey in 1993. During an evaluation in 2007, the criteria rarity and regional importance qualified it as valuable geological object. In 2010, the Alpine Club Garmisch-Partenkirchen and the History Club "Bear and Lily" of Grainau decided to establish the Hoellental Museum, close to the lower entrance (1020m a.s.l.) of the gorge.

The Hoellental Museum opened on July-01-2011. Its scope is to inform about the geological and geomorphological history of the gorge (1), its public perception and the history of its exploration and opening up (2) as well as the productive phases of the historical mine Knappenhaeuser close to the gorge (3).

1: The large Hoellental concavity originated at a major fracture zone, cut through the Wetterstein Limestone Formation: Late Anisian to Early Carnian deposits of tropical reefs and lagoons, which drowned during the Carnian Crisis. The deposits were deformed, thrusted northward and uplifted during the Tertiary after closure of the Alpine Tethys. Export of several km³ of particulate matter was accomplished by gravitative, fluvial and - since 2,6 Ma - also by glacial processes. The fact that the natural fall increased down-valley, tractive forces diminished lateral and intensified vertical glacial erosion, which favoured the development of the gorge. In addition, karstification enhanced downward erosion.

2: It is documented that Höllental was explored in the year 1622. Later on, foot-paths were prepared for mining work. In 1888 the gorge was bridged 73m above ground. The line of construction with tunnels and staircases through the gorge was done by civil engineering between 1902-1905.

3: Between 1827-1861 and 1907-1925, Knappenhaeuser (1520m a.s.l.) - one of the topographically highest historical mine of FRG - yielded galena, sphalerite and wulfenite. The source of the fault-bounded, redeposited ores probably represented the adjacent Raibl Boundary Layer.