Structural characteristics of the curved Königsee-Lammertal-Traunsee fault system in Salzkammergut (Northern Calcareous Alps, Austria)

Abstract

In the Miocene, the Eastern Alps (Austria) experienced strike-slip faulting, due to Eastward extrusion tectonics. Sinistral movement along the Salzach-Ennstal-Mariazell-Puchberg fault, with transpressive and strike-slip tectonics, resulted into N–S and SW-NE compression in the Northern Calcareous Alps (NCA). That led to the development of several faults, including the Königsee-Lammertal-Traunsee (KLT): a sinistral fault cross-cutting the NCA with a curved path. Here, we focus on the eastern termination of the KLT, previously interpreted as two SSW-NNE and SW-NE strike-slip faults, connected by an E-W thrust with top-to-NE motion. Our structural/petrographic data indicate that the two sectors of the KLT are linked also by an E-W strike-slip fault, between Triassic carbonates and Late Cretaceous clastics. The associated damage zone is complex and includes strike-slip duplexes and small-scale thrusts, associated to various fault rocks. Furthermore, our new data indicate that the E-W oriented thrust is confined between two stepping strike-slip fault, suggesting a restraining bend, like other sectors of the KLT.The structure of the KLT, with the strike-slip segments characterized by small-scale duplexes and flowers, but where significant shortening is mainly accommodated within the restraining area closely resembles that of other strike-slip systems, which typically extended over hundreds of km.