Hydrogeological properties of fault zones in a karstified carbonate aquifer (Northern Calcareous Alps, Austria)

Abstract

This study presents a comparative, field-based hydrogeological characterization of exhumed, inactive fault zones in low-porosity Triassic dolostones and limestones of the Hochschwab massif, a carbonate unit of high economic importance supplying 60 % of the drinking water of Austria's capital, Vienna. Cataclastic rocks and sheared, strongly cemented breccias form low-permeability (<1 mD) domains along faults. Fractured rocks with fracture densities varying by a factor of 10 and fracture porosities varying by a factor of 3, and dilation breccias with average porosities >3 % and permeabilities >1,000 mD form high-permeability domains. With respect to fault-zone architecture and rock content, which is demonstrated to be different for dolostone and limestone, four types of faults are presented. Faults with single-stranded minor fault cores, faults with single-stranded permeable fault cores, and faults with multiple-stranded fault cores are seen as conduits. Faults with single-stranded impermeable fault cores are seen as conduit-barrier systems. Karstic carbonate dissolution occurs along fault cores in limestones and, to a lesser degree, dolostones and creates superposed highpermeability conduits. On a regional scale, faults of a particular deformation event have to be viewed as forming a network of flow conduits directing recharge more or less rapidly towards the water table and the springs. Sections of impermeable fault cores only very locally have the potential to create barriers.

Validating the KAGIS black‐box GIS‐based model in a Mediterranean karst aquifer: Case of study of Mela aquifer (SE Spain)

“…KAGIS detected only small increments of porosity around 731 masl, and so, it can be considered that variation in this parameter in Mela aquifer is not important and there are no depths with different hydrodynamic behaviours. These values match with the characteristic value of pore volume in karst aquifers as it has been shown in other studies (Bauer, Schröckenfuchs, & Decker, 2016;Różkowski & Różkowski, 2016).…”

Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

“…Bauer et al (2016) concluded that, on a regional scale, faults of a particular deformation event have to be viewed as forming a network of flow conduits directing recharge more or less rapidly towards the water table and the springs. In addition, these faults are very important in influence positively on groundwater occurrences and acting as transmission routs in the limestone bodies' conduits for transporting and storing the included groundwater.…”

Geostructural mapping of karstifid limestones

“…Nevertheless, it is inadequate for a full understanding of individual local relationships. Only a detailed consideration of different degrees of fracturing (Čar, 1982Bauer et al, 2016) can yield sufficient information to enable interpretations of the dimensions and shaping of particular phenomena, their dependence upon structural controls (especially the degree of fracturing) and the history of their genesis.…”