Mechthild Doll

Calabrian Arc Mud Volcanoes: Deep Origin, internal Structure and Activity

Mud volcanoes (MVs) may be found in marine and terrestrial geological settings but are predominantly known from compressional tectonic regimes (e.g. accretionary wedges) on Earth. In general, mud volcanism is driven by the upward migration of overpressured fluids inducing a sediment mobilization and the extrusion of mud breccia onto the surface. The repeating extrusion of mud breccia leads to a build-up of an edifice from which individual mudflows progressing downslope.  MVs are typically linked to hydrocarbon systems and, under certain temperature and pressure conditions, able to host gas hydrates within the sediment.

The Calabrian Arc is situated in the Eastern Mediterranean Sea east of Sicily. About 54 distinct MVs have been identified in this region. The general role of the Calabrian Arc MVs in the Eastern Mediterranean Sea is relatively poorly understood but its presence can be easily related to the subducting African Plate beneath the European Plate. This results in the formation of an accretionary complex extending over 1500 km from Calabria to Cyprus.

The PhD Project is focusing on a better understanding of the deep origin, internal structure, temporal evolution and activity of the Calabrian Arc MVs using sedimentological and geophysical data from three expeditions (M112, POS499, POS515). High resolution bathymetry data obtained from an autonomous underwater vehicle are used to characterize mudflows and distinguish individual seafloor expressions of the MVs. In addition, backscatter data are used to identify mudflows in the shallow seabed. Moreover, the interpretation of data from ocean bottom seismometers as well as 2D and 3D seismic data, is used to describe the deeper structure of the MVs in the Calabrian Arc in more detail. Finally, sediment cores are examined to describe the activity and individual mud extrusion events of the individual MVs over the past.

The results contribute to a better understanding of the formation and evolution of Calabrian Arc MVs as well as the tectonic activity behavior in the Eastern Mediterranean Sea. Moreover, the results will improve the knowledge about MVs in terms of ongoing changes and to reconstruct its evolution over the past. A better knowledge of MVs is contributing to a better understanding of geohazards, hydrocarbon reservoirs and lithosphere-ocean-atmosphere interactions related to mud volcano activity.