Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

464 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E PATA Days 2024 Jacek Szczygieł* (1, 2) Bernhard Grasemann (2) Lukas Plan (3) John Hellstrom (4) (1) Institute of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland (2) Department of Geology, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria (3) Cave and Karst Group, Dep. of Geology and Paleontology, Natural History Museum, Burgring 7, 1010 Vienna, Austria (4) School of Earth Sciences, McCoy Building, Cnr Swanston and Elgin Streets, University of Melbourne, Parkville, 3010, Victoria, Australia *Email: jacek.szczygiel@us.edu.pl K E Y W O R D S tectonic extrusion; neotectonics; fractured speleothems; paleostress; Eastern Alps LATE PLEISTOCENE TRANSPRESSION OF THE KÖNIGSSEE–LAMMERTAL–TRAUNSEE FAULT INFERRED FROM CAVES DEFORMATION (EUROPEAN EASTERN ALPS) A B S T R A C T We show that the Königssee–Lammertal–Traunsee (KLT) fault, one of the major strike-slip systems in the European Alps, was active during the Pleistocene. Paleostress reconstruction indicates that the KLT fault accommodates the North-South shortening of the Northern Calcareous Alps. While the major tectonic activity along this fault occurred during the Oligocene and Miocene periods, it has been unknown whether the fault has remained active up to the present day. Here, we present the first constrained in time and field evidence of the late Pleistocene activity observed within caves located in the Göll, Hagengebirge, and Tennengebirge karst massifs in Austria, which are bounded by the KLT fault. Damaged speleothems resulting from cave passage offsets, dated using the Th/U method, constrain tectonic event timing, ranging from 539 (+110/-72) ka to 92.0 ± 1.2 ka. I N T R O D U C T I O N While the Central and Western Alps form the primary topographic backbone of the orogeny, the Eastern Alps have experienced more recent tectonic activity, attributed to a shift in north-south convergence resulting from the northeastward drift of the Adria plate (Sternai et al., 2019 and references therein). This oblique convergence has led to lateral extrusion along strike-slip and normal faults, shaping the tectonic and morphological evolution of the Eastern Alps since the late Oligocene (Ratschbacher et al., 1991). Despite the present-day instrumentally measured activity