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.

Shaking Scenarios from Multiple Source Models Shed Light on the 8 September 1905Mw 7 Calabria Earthquake (Southern Italy)

“…1) support the hypothesis that subduction of the oceanic crust is still active beneath the Calabrian block and is laterally constrained by two main tear faults, the Tindari fault (to the south) and the likely Cirò-Benevento fault (to the north; Fig. 1; Van Dijk and Scheepers, 1995;Faccenna et al, 2001Faccenna et al, , 2014Rosenbaum et al, 2008;Orecchio et al, 2014). Collision and subduction processes could also be responsible for the intense fragmentation of the Calabrian arc in blocks bounded by the northwestsoutheast-striking shear zones ( Fig.…”

Onshore to offshore correlation of regional unconformities in the Plio-Pleistocene sedimentary successions of the Calabrian Arc (central Mediterranean)

“…2) contains a record of subsidence interrupted by episodes of uplift and deformation (Roda, 1964;Van Dijk, 1990;Zecchin et al, 2006;Massari et al, 2010;Zecchin et al, 2012). Unconformities and deformation structures within the basin are interpreted to indicate short-term compressional or transpressional phases in mid-Messinian, earliest mid-Pliocene and mid-Pleistocene times (Van Dijk, 1990Van Dijk and Okkes, 1991;Van Dijk and Scheepers, 1995;Massari et al, 2010;Zecchin et al, 2012). The shear zones bounding the Crotone Basin are inferred to have strongly influenced the architecture of the Plio-Pleistocene basin fill (Zecchin et al, 2012;Massari and Prosser, 2013).…”

“…Episodic subduction zone retreat has taken place due to changes in the geometry of the downgoing slab, involving stepwise narrowing conditioned by interference with continental blocks of the adjacent southern Apennines, Apulia and Sicily (Faccenna et al, 2001(Faccenna et al, , 2004Chiarabba et al, 2008;Guillaume et al, 2010). This complex Neogene geodynamic evolution has had consequences for the structural and stratigraphic records of the Apennines that are difficult to unravel, as reflected in the range of reconstructions that have been proposed (e.g., Rehault et al, 1987;Patacca et al, 1990;Sartori, 1990;Knott and Turco, 1991;Van Dijk and Scheepers, 1995;Schettino and Turco, 2011).…”

A study of melt inclusions at Vulcano (Aeolian Islands, Italy): insights on the primitive magmas and on the volcanic feeding system

“…The island of Vulcano is located, with Lipari and Salina, within a deep graben that is oriented roughly north, orthogonal to the volcanic arc ), and appears to be strictly linked to the Tindari-Letojanni strike-slip fault. The volcanic pile lies on metamorphic units probably corresponding to the Calabrian Arc van Dijk and Scheepers 1995). Partially molten xenoliths of metamorphic rocks, isotopically and mineralogically similar to the Calabrian units, have been found in the Vulcano products (Keller 1980;Clocchiatti et al 1994a;Del Moro et al, 1998) as well as in other Aeolian Islands.…”