Mud volcanoes along the inner deformation front of the Calabrian Arc accretionary wedge (Ionian Sea)

We present geophysical data integrated with the analysis of well-targeted sediment samples in order to contribute to a better understanding of fluid circulation in the Calabrian Arc accretionary wedge. Two cores (BS81/II 5 and BS81/II 10) collected on a swell in the hangingwall of the inner deformation front show upper Pleistocene mud breccias that include Cretaceous to Late Miocene rock fragments mechanically incorporated into the eruption deposit by the upward transport of overpressured fluids. An additional core (CALA 21) came from the summit of a topographic high in the footwall of the inner deformation front of the accretionary wedge and contains a mud breccia patchy/cloudy facies where sediment disturbance is caused by fluid expulsion. Integration of the entire data set provides evidences of the interplay among tectonics, fluid emissions and sedimentation, and enables the identification of two new volcanoes in the accretionary prism where overpressuring due to Pliocene and Pleistocene sediment accumulation and the evolution of active fault systems triggered fluid circulation and the formation of those structures.

► Two new mud volcanoes at the Calabrian Arc have been discovered.
► Massive and patchy/cloudy mud breccia are evidence of diverse energy of fluid flow.
► Massive mud breccia marks the extrusion of deep-seated clay-rich formations.
► Mud breccia patchy/cloudy is produced by local fluid remobilization.
► Mud volcanoes could have deeply rooted conduits.