A geological cross section through the Variscides in the German Democratic Republic (Eastern Erzgebirge, Central Saxonian Lineament, Saxonian Granulite Complex, Harz Mountains).

Abstract

Two cross sections of the Variscides in the territory of the GDR are described. The section of the Saxothuringian Zone (Eastern Erzgebirge, Central Saxonian Lineament, Granulite Complex) includes deeper tectonic levels with metamorphic rocks of Barrow type (Erzgebirge) and granulite facies (Granulitgebirge). In shear zones in the Central Saxonian Lineament low-grade, high-pressure rocks with a tendency to glaucophanitic facies occur. Intercalated mafic and ultramafic rocks are considered to be tectonically displaced relics of the upper mantle. The cross-section of the Rheno-Hercynian Zone (Harz Mountains) demonstrates a higher tectonic level with tectonic structures and rocks typical of slate regions and a low to very low grade of metamorphism. Whilst in the Saxothuringian Zone the vertical component is stronger, horizontal movements directed towards the margin of the orogeny dominate in the internal Rheno-Hercynian zone. Therefore in the Harz a strong NW-vergence and gravitational sliding is exhibited (i.e. olistostromes and downsliding nappes).