Status: this preprint was under review for the journal SE but the revision was not accepted.
Slab Break-offs in the Alpine Subduction Zone
Emanuel D. Kästle,Claudio Rosenberg,Lapo Boschi,Nicolas Bellahsen,Thomas Meier,and Amr El-Sharkawy
Abstract. After the onset of plate collision in the Alps, tectonic processes are inferred to have changed dramatically in the Alps: European plate break-offs in various places of the Alpine arc, as well as a subduction polarity reversal in the eastern Alps have been proposed. We review body-wave tomographic studies, compare them to our surface-wave-derived model, and interpret them in terms of slab geometries. We infer that the shallow subducting portion of the European plate is likely detached under both the western and eastern (but not the central) Alps. The Alps-Dinarides transition may be explained by a combination of European and Adriatic subduction. This implies that the deep high-velocity anomaly (> 200 km depth) mapped by tomographers under the eastern Alps is a detached segment of the European plate. The shallower fast anomaly (100–200 km depth) can be ascribed to European or Adriatic subduction, or both. These findings are compared to previously proposed models for the eastern Alps in terms of slab geometry, but also integrated in a a new, alternative geodynamic scenario that best fits both tomographic images and geological constraints.
How to cite. Kästle, E. D., Rosenberg, C., Boschi, L., Bellahsen, N., Meier, T., and El-Sharkawy, A.: Slab Break-offs in the Alpine Subduction Zone, Solid Earth Discuss. [preprint], https://doi.org/10.5194/se-2019-17, 2019.
Received: 24 Jan 2019 – Discussion started: 31 Jan 2019
We provide an extensive comparison of high-resolution subsurface models of the Alpine subduction zone. The imaged slab geometries are discussed in relation to the geodynamic evolution of the Alpine region. In the eastern Alps, we compare the models to three scenarios from the literature and propose a fourth one which best fits the tomographic images and the geological constraints. We find that the European slab is broken off below the entire Alpine arc, at variable depth levels.
We provide an extensive comparison of high-resolution subsurface models of the Alpine subduction...