FFG Bridge 2021: Evaporite tectonics and paleogeography in the Alps of the Salzkammergut (ETAPAS)

In collaboration with: Salinen AG and Universität Innsbruck

Financial support: 300.986,00 EUR

Research Team:

Oscar Fernandez Bellon (Principal Investigator)
Bernhard Grasemann

The Northern Calcareous Alps in the area of the Salzkammergut are characterized by the presence of abundant accumulations of Permo-Triassic evaporites, some of which are currently exploited through mining. Evaporite accumulations have puzzled geologists as they are covered by deep-water sediments despite being surrounded by shallow water carbonate platforms. The current understanding to account for this observation is that the evaporite bodies are highly allochthonous units emplaced gravitationally during the early stages of the Alpine orogeny. Recent research points to a possible alternative origin of at least some of these bodies, as diapirs that developed during Triassic and Jurassic times in their current position relative to the surrounding carbonate platforms. This does not however fully explain the origin of the deep-water sediments that accompany the evaporite accumulations.

The objective of ETAPAS is to revisit the geology of the Salzkammergut and the Northern Calcareous Alps under the light of our modern understanding of salt tectonics and to develop an integrated geological model to account for the geological observations accumulated in the region over the last decades. This will be done through the integration of structural geology and sedimentology, with the aim of understanding the paleogeographic evolution of the Northern Calcareous Alps, from its configuration as a passive margin in the Triassic, up to its involvement in the Alpine orogeny from Cretaceous times onwards. Work will include field work to revise existing geological maps, subsurface geology to clarify the structure of the currently mined evaporite bodies, laboratory work for sedimentological and structural analysis of rock samples, and the construction and restoration of balanced cross-sections.

Ultimately, ETAPAS will provide a better understanding of the distribution of evaporites in the Alpine subsurface and the origin of their emplacement. This will have a major impact on the current understanding of Alpine orogen development and will provide a framework in which the future evaporite prospectivity of the Salzkammergut can be evaluated.

Panorama Bad Ischl - Altaussee

Panorama Bad Ischl - Altaussee (© O. Fernandez Bellon)