Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Abstract (EDOC: 2372)
Major bodies of high-pressure (HP) rocks in the Saxo-Thuringian Belt in East Germany (Saxonian Granulite Massif, Erzgebirge) are investigated using a variety of geophysical methods (seismic reflection and refraction survey, magnetotelluric studies, gravity modelling). The Saxonian Granulite Massif and the Erzgebirge are not a continuous feature, as can be see from discontinuous reflections, offset of upper-crustal seismic refraction velocity layers, and crustal resistivity increasing towards the Erzgebirge. Their juxtaposition during the evolution of two Variscan-age thrust wedges may have controlled from the southeast to the northwest onto the Saxo-Thuringian Basin, whereas the later one propagated southwards and uplifted the Saxo-Thuringian granulites from deeper levels. To the southwest, the granulites are observed at shallow depth as far as the Franconian Line; to the southeast they extend down to the Moho, or they continue at mid-crustal levels. The granulites beneath the Saxo-Thuringian Belt can only have originated in one of two subduction zones: either through 'subduction erosion' and subsequent underplating of parts of the Saxo-Thuringian Plate from the north, of by intracrustal plug flow of overheated material from the southeast.
(2000): Geophysical constraints on exhumation mechanisms of high-pressure rocks : the Saxothuringian case between the Franconian Line and Elbe Zone. - In: Franke, W.; Haak, V.; Oncken, O. (Eds.), Orogenic processes : quantification and modelling in the Variscan Belt, Geological Society, 303-322.