Technischer Bericht NTB 90-03

This report deals predominantly with brittle deformation in the basement of the Southern Black Forest. During the course of a study of the structural geology of this region, it became apparent firstly that there was a need to refine the data acquisition process using new measuring points and, secondly, that the role of fault zones in the crystalline basement required more detailed investigation.

The report concentrates mainly on the second objective. The first part outlines the basic principles of block tectonics and discusses relevant models and development sequences. A description of selected discontinuities (strike-slip faults, tension structures) completes the general overview of block tectonics. Wherever possible, specific examples from the investigation area have been selected. However, it also proved necessary to include descriptions from the literature because, in the basement of the Southern Black Forest, it is difficult to find case studies for which the structural geology can be analysed at sufficient depth.

The second part of the report contains a discussion of general aspects of brittle deformation of the basement; this is complemented by a series of geographically and thematically restricted studies of specific topics. These include an analysis of the data acquired during construction of the underground hydroelectric power plant at Wehr, a regional study in the area between Waldshut and Grafenhausen which looks at the relationship between morphostructural elements and the tectonic structure of the basement and, finally, a special study carried out in the area between Hauenstein and Waldshut which investigates the tectonic significance of a series of NNW-SSE-striking valleys. These special studies are finally discussed from the point of view of acquisition, evaluation and extrapolation of structural geology data.