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Post-Eocene faults in central and southern Germany: can we find them?

The Site Selection Act (StandAG) for Germany´s nuclear waste repository states that the presence of post-Eocene (< 34 Ma old) faults is an exclusion criterion that makes any potential site unsuitable. Identifying such faults is problematic in the German uplands (Mittelgebirge), where large areas have no Cenozoic deposits and exposure quality is generally low. Radiometric age dates of faults are still very sparse and unlikely to become widely available in the near future. We have used different methods to identify potential post-Eocene faults. These include GIS-based analysis of the spatial relationships of faults with post-Eocene units on existing maps as well as automated lineament extraction and visual interpretation of possibly fault-related topographic features from high-resolution DEMs. Fault and lineament density maps were created. All results based on geological maps are affected by their uneven quality and inconsistency. Much of the variation is caused by different mapping concepts, particularly for the 1:25.000 sheets. The fault networks have been analyzed for fault length distribution and topology to identify interpretation problems. Fault lengths and connectivity are underestimated. A Python code has been developed to automatically extract stratigraphic throws of faults from digital geological maps with an aim being to make better predictions about fault trace lengths. A concept for safety distances around faults has been developed that considers not only wall damage along faults, but also damage at fault tips, bends, steps and interaction zones. Proof of post-Eocene faulting will require additional analyses for each suspected case.

Details

Author
Ali Abdelkhalek1, David Charles Peter Peacock1, Jonas Kley1
Institutionen
1University of Göttingen, Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/xz6n-gz51