Quartärmächtigkeiten in den Haupttälern der Zentralschweiz

In the course of TGK's hydrocarbon exploration activity, gravimetric reflection- and refraction surveys were carried-out in central Switzerland. The measurements provided new information on the nature of the quaternary valley fills. In parallel, the Obwalden valley was investigated in an ETH pilot study. Using the results of these investigations as well as already existing geological and geophysical data, quaternary - base elevation maps were constructed for the main valleys of Obwalden, Nidwalden and northern Uri. Due to the lack of detailed information, the rock surface in the Engelberg region, could only be defined by individual profiles. Data interpretation confirms older indications according to which the alpine valleys of central Switzerland deeply extend down to approximately sea level. The locally variable erosional strength of glaciers led to a distinct morphology of the rock surface. Geophysical interpretations indicate a close relationship between the shape of alpine valleys and fault systems in the underlying rocks.