Nele Behrendt

Fluid-rock interaction in serpentine- and clay-bearing deposits from mud
volcanoes and fault zones: A multimethodological approach

Mud volcanism is a global phenomenon that can be found offshore and onshore in a variety of geological settings. Its occurrence is mostly associated with compressional tectonics and sediment accretion and is mostly initiated by over-pressured subsurface fluids. The positive surface expressions are often called mud volcanoes (MVs) or mud domes and consist of mobilized sediments and clasts.

Within my PhD project I focus on fluid-rock interaction in serpentine- and clay-bearing deposits from subduction zone-related MVs and fault zones. Sediment cores and pore water samples will be examined regarding their mineralogy, chemical and isotopic signature as well as their physical properties. The project is funded through the Cluster of Excellence > The Ocean Floor – Earth`s Uncharted interface < and is part of the research Unit > Ocean Floor as Reactor < at the Center for Marine Environmental Sciences – MARUM in Bremen.

Main study area of my PhD project is the Mediterranean Ridge (MedRidge) Accretionary Complex in the Mediterranean Sea south of Greece. The accretionary complex is caused by the subduction of the African Plate beneath the Eurasian Plate (Hellenic Subduction Zone) and hosts several (> 150) MVs and mud structures. Thrust faults within the accretionary complex allow fluid and sediment migration and support the formation of mud volcanoes through over-pressured fluids.  

A multimethodological approach involving mineralogy, petrology, geochemistry, and geotechnical methods will be used to determine the morphological and structural context between the different mud volcanoes and fault zones within the accretionary complex. For this purpose, I work with previously examined material collected during the Poseidon Cruise P410, that will be supplemented with material from the upcoming expedition with R/V Meteor in November 2020 (M168).