High-stress creep in amphibolite-facies ultramylonites hosting pseudotachylytes: ductile instability or brittle failure?

Simone Papa1, Giorgio Pennacchioni1, Luca Menegon2,3 and Marcel Thielmann4, (1)University of Padova, Department of Geosciences, Padova, Italy, (2)Plymouth University, School of Geography, Earth and Environmental Sciences, Plymouth, PL4, United Kingdom, (3)University of Oslo, Oslo, Norway, (4)Universität Bayreuth, Bayerisches Geoinstitut, Bayreuth, Germany