Calabrian Arc Mud Volcanoes: Deep Origin, internal Structure and activity from data acquired during expeditions POS499, POS515, and M112

• Applicants: Professor Dr. Gerhard Bohrmann; Dr. Michael Riedel
• Subject Area: Palaeontology ; Geophysics
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 411262481

• Final Report Year: 2024

Final Report Abstract

The project CALVADOS successfully addressed questions about the evolution of mud volcanoes (MV) in the Calabrian arc by combining data from four research expeditions. Sediment core analyses, ship-based backscatter data, high-resolution AUV mapping, PARASOUND acoustic sub-bottom profiler data, as well as 2D and 3D multichannel seismic (MCS) and wide-angle ocean-bottom-seismometer (OBS) studies yielded a wealth of information constraining the structure and mud-flow evolution at Venere and Sartori MV. The core and seismo-acoustic information at Sartori MV showed that the mud extrusion rate decreased over the past 60 ka by three orders of magnitude. Sartori MV is currently at a rather dormant stage although geothermal data, AUV-mapping, and pore-fluid analyses indicate two eruption centres, but little to no recent mud extrusion. Reflection seismic and wide-angle OBS data revealed a complex history at Venere MV. The previously established recent (< 4000 yrs) history of mud volcanism around two prominent mud-cones was defined from AUV mapping, seafloor video-imaging, and sediment core analyses. The seismic data at Venere MV show instead that the double-cones represent a more recent evolutionary phase of Venere MV and that the MV initially encompassed a region at least twice in diameter than the recent cones suggest. The older, original structure at Venere MV likely consisted of a broad mud-pie with an outer rigid rim such as seen at Cetus MV. The original structure was gradually covered (draped) by hemipelagic sediments through steadily decreasing extrusion rates. In a new active extrusion phase, the old structures were broken up and partially remobilized, leading to the double cone visible today. Overall, Venere SV shows no extensive mud flows as mapped in Sartori SV, which indicates a different composition and viscosity of the extruded material.

Publications

• Internal Structure of Venere Mud Volcano in the Crotone Forearc Basin, Calabrian Arc, Italy, from Multibeam Bathymetry, Wide-Angle and Multichannel Seismic Data.
  Riedel, Michael; Krabbenhoeft, Anne; Papenberg, Cord; Bialas, Joerg; Bohrmann, Gerhard & Ceramicola, Silvia
  
• Mud volcanoes along the Euro-African collision zone in the eastern Mediterranean Sea, Statuskonferenz Forschungsschiffe, 5-6 March 2024, Bremen
  Bohrmann et al.
  
• Recent activity and evolutionary reconstruction of Sartori mud volcano in the Calabrian Arc, Mediterranean Sea, GIMS15, Cádiz, Spain, 23-27 October 2023
  Doll M. et al.
  
• Recent and episodic activity of decoupled mud/fluid discharge at Sartori mud volcano in the Calabrian Arc, Mediterranean Sea. Frontiers in Earth Science, 11.
  Doll, Mechthild; Römer, Miriam; Pape, Thomas; Kölling, Martin; Kaul, Norbert; dos Santos, Ferreira Christian & Bohrmann, Gerhard