The tectonic border between Lusatian Massiv and Erzgebirge – First results from drillings of a planned tunnel project (railway Dresden – Prague)

The Elbtalschiefergebirge - the tectonic border between the Lusatian Massiv and the Erzgebirge – is limited by two large regional faults, the West Lusatian fault and the Mid Saxonian fault. In Saxony, both NW-SE striking faults are running mostly parallel. So, a generally cogenetic evolution of both structures was assumed until now.

The paleozoic units of the Elbtalschiefergebirge itself are limited very often also by faults. However, deep drillings are missing until now.

During the still running project „Railway tunnel Dresden-Prague“ several geological units and faults are exposed by numerous drillings up to 400 m depth.

The new results show, that the West Lusatian fault as thrust zone and the Mid Saxonian fault as shear zone are not comparable as well in time as in genesis. The thickness of the Mid Saxonian fault is proved by drillings of at least 900 m. On the other hand, the fault volume of the West Lusatian fault includes only several meter. This is untypical for such a regional fault zone, but the main movement seems to have taken place about 300 m south of the recently mapped fault position.

Instead this, the faults in the Elbtalschiefergebirge are thrusts with considerable displacement.

The drillings of the ongoing project will just be investigate by several research groups of different institutions. Numerous new drillings in special areas are planned in the next years.