200 000 years of glacially induced faulting in the Tornquist Fan area, SW Baltic Sea.

We present a comparative study of the glacially induced fault reactivation within the Southern Baltic Sea since the Upper Saalian. A complex tectonic pattern characterizes the Tornquist Fan, which spans between the Tornquist Zone in the North and the Trans European Suture Zone in the South. Multiple fault zones result from the varying transpressional and transtensional stress activities since the Paleozoic. The current tectonic pattern of this unique natural laboratory is composed of several faults with varying strike and dip directions, depths and characters (normal, reverse, strike slip). Moreover, some shallow faults are associated with Zechstein salt pillows, and others are related to anticlines formed during the Cretaceous to Paleogene compression.

Using finite-element simulations of different glacial isostatic adjustment models (varying the material parameters in the Earth and the ice history), we obtained glaciation induced Coulomb failure stress changes (∆CFS) at the faults over time, covering the past 200 ka. Comparing the activation potential of several faults of different tectonic background reveals the impact of the varying crustal and fault properties, as well as the influence of salt structures below. Besides lateral differences in the ∆CFS due to the changing geology, we see temporal differences, by comparing the occurrence of glacially induced faulting with different ice advances.