Neotectonic rotations in the Calabrian Arc; implications for a Pliocene-Recent geodynamic scenario for the Central Mediterranean

Abstract

Recently, new data have been presented which imply that major block rotations took place in the Central Mediterranean during the Pleistocene, between 1.0 and 0.7 Ma. Kinematic solutions for the spatial and temporal distribution of rotational data in the Central Mediterranean such as oroclinal bending of the Calabrian Arc and rotation of the Adria Plate are being discussed. Phases of neotectonic rotations appear to be confined to distinct phases of contractions and compressive interplate stress. We present a model in which the middle Pleistocene rotations are caused by a distribution of deformation in the Central Mediterranean through strike-slip motions along a number of major shear zones which define a free boundary between the African and the Adria Plates. One of the main features is the Trans-Mediterranean Mobile Zone, which separates areas with opposite rotations. The timing of the rotations is compared to the evolution of volcanism, basin development, subsidence and uplift patterns, contractional tectonics and seismicity patterns. From this comparison we hypothesize that the Late Pliocene-Recent geodynamic evolution of the Central Mediterranean comprises the following three episodes: (1) A Late Pliocene arc migration episode shows drifting of the Calabrian block and spreading of the back-arc basin without the associated oroclinal rotations that were previously assumed in literature. (2) An Early Pleistocene contraction episode shows a gradual increase of compressive interplate stress, and culminates in a middle Pleistocene “stress release phase” which is associated with block rotations, transpressional tectonics and a rupturing of the subducted slab. (3) A Late Pleistocene-Recent restabilisation episode is characterized by rapid isostatic adjustments, with extensional collapse of the Apennine thrust-wedge and the Tyrrhenian back-arc area related to rebound of non-detached lithosphere remnants and sinking into the mantle of the detached slab.