Ophiolite‐bearing mélanges in southern Italy

In southern Italy two ophiolite-bearing belts, respectively involved in the Adria-verging southern Apennines and in the Europe-verging thrust belt of the northern Calabrian Arc, represent the southward extension of the northern Apennines and of ‘Alpine Corsica’ ophiolitic units, respectively. They form two distinct suture zones, which are characterized by different age of emplacement and opposite sense of tectonic transport. The ophiolite-bearing units of the southern Apennines are represented by broken formation and tectonic melange associated with remnants of a well-developed accretionary wedge emplaced on top of the Adria continental margin, with an overall NE direction of tectonic transport. These units consist of a Cretaceous-Oligocene matrix, which includes blocks of continental-type rocks and ophiolites with remnants of their original Upper Jurassic to Lower Cretaceous pelagic cover. The innermost portion of the accretionary wedge is represented by a polymetamorphosed and polydeformed tectonic units that underwent a Late Oligocene high pressure/low temperature (HP/LT) metamorphism. The northern Calabria ophiolitic-belt is indeed composed of west-verging tectonic slices of oceanic rocks which, embedded between platform carbonate units of a western continental margin at the bottom and the basement crystalline nappes of the Calabrian Arc at the top, are affected by a Late Eocene-Early Oligocene HP/LT metamorphism. The main tectonic features of these two suture zones suggest that they can be interpreted as the result of the closure of two branches of the western Neotethys separated by a continental block that includes the crystalline basement rocks of the Calabrian Arc. We thus suggest that the north-east verging southern Apennine suture constituted by a well-developed accretionary wedge is the result of the closure of a large Late Jurassic-Early Cretaceous oceanic domain (the Ligurian Ocean) located between the African (the Adria Block) and European continental margins. The northern Calabria suture derives indeed from the deformation of a very narrow oceanic-floored basin developed during the Mesozoic rifting stages within the European margin separating a small continental ribbon (Calabrian Block) from the main continent. Copyright © 2008 John Wiley & Sons, Ltd.

[1]  V. Perrone,et al.  Tectono‐sedimentary evolution of the southern branch of the Western Tethys (Maghrebian Flysch Basin and Lucanian Ocean): consequences for Western Mediterranean geodynamics , 2005 .

[2]  C. Scotese,et al.  Global kinematic constraints to the tectonic history of the Mediterranean region and surrounding areas during the Jurassic and Cretaceous , 2002 .

[3]  P. Vannucchi,et al.  Structural style of the offscraped Ligurian oceanic sequences of the Northern Apennines: new hypothesis concerning the development of mélange block-in-matrix fabric , 2003 .

[4]  C. Faccenna,et al.  Alpine structural and metamorphic signature of the Sila Piccola Massif nappe stack (Calabria, Italy): Insights for the tectonic evolution of the Calabrian Arc , 2001 .

[5]  V. Bortolotti,et al.  Tethyan ophiolites and Pangea break‐up , 2005 .

[6]  G. Lister,et al.  Neogene and Quaternary rollback evolution of the Tyrrhenian Sea, the Apennines, and the Sicilian Maghrebides , 2004 .

[7]  E. Piluso,et al.  Geodynamic significance of ophiolites within the Calabrian Arc , 2006 .

[8]  V. Perrone,et al.  THE EVOLUTION OF THE NORTHERN SECTOR OF THE CALABRIA-PELORITANI ARC IN A SEMIQUANTITATIVE PALYNSPASTIC RESTORATION , 1982 .

[9]  C. Monaco,et al.  Structural evolution of the Lucanian Apennines, southern Italy , 1998 .

[10]  L. Jolivet,et al.  Lateral slab deformation and the origin of the western Mediterranean arcs , 2004 .

[11]  C. Invernizzi,et al.  Structural signature of tectonic processes in the Calabrian Arc, southern Italy: Evidence from the oceanic-derived , 1996 .

[12]  Carmelo Monaco,et al.  Tectonic role of ophiolite‐bearing terranes in the development of the Southern Apennines orogenic belt , 1995 .

[13]  V. Perrone,et al.  Calabria-Peloritani terrane and northern Ionian Sea , 2001 .

[14]  A. Carrara,et al.  Alpine structures in northwestern Calabria, Italy , 1976 .

[15]  V. Perrone,et al.  Late Oligocene-Miocene syn-/-late-orogenic successions in Western and Central Mediterranean Chains from the Betic Cordillera to the Southern Apennines* , 1993 .

[16]  F. Golfetto,et al.  A regional structural model for the northern sector of the Calabrian Arc (southern Italy) , 2000 .

[17]  I. Moretti,et al.  Late cenozoic subduction complex of Sicily , 1990 .

[18]  C. Monaco,et al.  From collisional to rifted basins: an example from the southern Calabrian arc (Italy) , 1996 .

[19]  D. Scrocca,et al.  Subduction kinematics and dynamic constraints , 2007 .

[20]  A. Schettino,et al.  Plate kinematics of the Western Mediterranean region during the Oligocene and Early Miocene , 2006 .

[21]  P. Olivier,et al.  Betic-Rifian and Tyrrhenian Arcs : Distinctive Features, Genesis and Development Stages , 1986 .

[22]  W. Alvarez,et al.  A former continuation of the Alps , 1976 .

[23]  C. Doglioni.  Main differences between thrust belts , 1992 .

[24]  Walter Alvarez,et al.  Structure of the monte reventino greenschist folds : a contribution to untangling the tectonic-transport history of Calabria, a key element in italian tectonics , 2005 .

[25]  L. Petronio,et al.  Crustal image of the Ionian basin and its Calabrian margins , 1996 .

[26]  C. Monaco,et al.  Neogene‐Quaternary tectonic evolution of the southern Apennines , 2004 .

[27]  L. Morten,et al.  The tectonic significance of the Diamante-Terranova unit (Calabria, southern Italy) in the Alpine evolution of the northern sector of the Calabrian Arc , 1991 .

[28]  C. Faccenna,et al.  Alpine orogenic P‐T‐t‐deformation history of the Catena Costiera area and surrounding regions (Calabrian Arc, southern Italy): The nappe edifice of north Calabria revised with insights on the Tyrrhenian‐Apennine system formation , 2004 .