Technischer Bericht NTB 84-30

Das Kristalin des Südschwarzwaldes

The crystalline basement of the northern part of Central Switzerland continues into the massif of the Black Forest, where due to strong uplift and erosion this basement can be studies in surface outcrops. In the project "Southern Black Forest" possible geological connections between the two regions are examined and similar lithological and structural situations are established.

In the first part of this report, the complex geological evolution of the basement in the Black Forest is reconstructed on the base of publications of various authors. The great lithological variation of the crystalline rocks is described in some detail; a list of all granites in the studied area is given in the appendix.

The main elements of the tectonic and structural history are reviewed in the second part. The basement of Southern Black Forest is subdivided into several large blocks which are separated by faults zones.

Discontinuities in the basement are described in the third part of this report. The methods for investigating structures of brittle deformation and the corresponding nomenclature are summarized. Preliminary data of a detailed analysis of joints in more than 40 localities suggest the existence of well defined fracture systems.