Styles and regimes of orogenic thickening in the Peloritani Mountains (Sicily, Italy): new constraints on the tectono-metamorphic evolution of the Apennine belt

Abstract

The Peloritani Mountains constitute the Sicilian portion of the Calabria–Peloritani Arc \ud (Italy), a tectono-metamor phic edifice recording the history of the subduction–exhumation cycle during \ud Tertiary convergence between the African and European plates. Here, we describe the kinematic and \ud the petrological characteristics of the major shear zones bounding the lowermost continental-derived \ud metamor phic units cropping out in the eastern portion of the Peloritani Mountains. Both meso- \ud and micro-scale shear sense criteria indicate a top-to-the-SSE tectonic transport, during a general \ud evolution from ductile to brittle deformation conditions. Quantitative thermobarometry on texturally \ud equilibrated phengite–chlorite pairs crystallized along the shear bands indicates pressure of 6–8 kbar \ud at temperatures of 360–440 ◦ C for the structurally highest units and 3–4 kbar at 380–440 ◦ C for the \ud lowest ones. This documents an overall inverse-type nappe ar rangement within the tectonic edifice \ud and a transition from an Alpine- (13–18 ◦ C km−1 ) to a Bar rovian-type (28–36 ◦ C km−1 ) geothermal \ud gradient during the progress of the Alpine orogenic metamor phism in the Peloritani Mountains. The \ud integration of these results allows the Peloritani Mountains to be considered as a constituent element \ud of the Apennine orogenic domain formed during the progressive space–time transition from oceanic \ud to continental subduction at the active convergent margin

Detecting the stepwise propagation of the Eastern Sicily thrust belt (Italy): insight from thermal and thermochronological constraints

“…The oldest Sicilian orogenic phase, during Eocene–Oligocene times, is represented by metamorphic overprinting of the crystalline internal units and by south‐verging nappe stacking. This Alpine tectono‐metamorphic event is recognized throughout the entire Calabrian Arc and represents the early orogenic growth, although different interpretations have been proposed in literature (Thomson, , ; Giunta and Somma, ; Messina et al ., ; Vignaroli et al ., ). The FTB evolution can be depicted as follows: Early wedge‐top deposition.…”

Contrasting styles of (U)HP rock exhumation along the Cenozoic Adria‐Europe plate boundary (Western Alps, Calabria, Corsica)

“…Differences in nappe architecture between northern and southern Calabria, the former showing both Europe and Adria verging structures and the latter exclusively Adria‐verging structures, led to the suggestion that these orogenic segments may represent two subterranes with distinct Cretaceous‐Paleogene tectonometamorphic evolution, juxtaposed only in Oligocene times [ Bonardi et al ., ]. However, recent works indicate that northern and southern Calabria had a common orogenic polarity toward the Adriatic foreland during crustal thickening and nappe stacking [ Rossetti et al ., , 2004; Vignaroli et al ., , 2012], which indicates that Calabria might instead represent a single terrane.…”

Seismotectonics of northeastern Sicily and southern Calabria (Italy): New constraints on the tectonic structures featuring in a crucial sector for the central Mediterranean geodynamics

“…The recent geodynamic evolution of the region (roughly the last 15 Myr) has been related to the opening of the Tyrrhenian Sea, coming with the rollback of the Ionian slab [ Malinverno and Ryan , ; Faccenna et al , ; Billi et al , ] and the east‐southeastward drift of the Calabro‐Peloritan Arc which overthrusted the Maghrebian domain [ Pepe et al , ; Vignaroli et al , ]. Currently, evidence of this subducted slab comes from the occurrence of intermediate and deep earthquakes (between 50 and 400 km) beneath the southern Tyrrhenian Sea along a NW dipping Benioff‐Wadati zone [ Anderson and Jackson , ; Giardini and Velonà , ] and from the tomographic images [ Chiarabba et al , ; Neri et al , , and references therein].…”