Deformation history of the ophiolite sequence from the Balagne Nappe, northern Corsica: insights in the tectonic evolution of Alpine Corsica

Abstract

In Alpine Corsica, the Jurassic ophiolites represent remnants of oceanic lithosphere belonging to the Ligure-Piemontese Basin located between the Europe/Corsica and Adria continental margins. In the Balagne area, a Jurassic ophiolitic sequence topped by a Late Jurassic-Late Cretaceous sedimentary cover crops out at the top of the nappe pile. The whole ophiolitic succession is affected by polyphase deformation developed under very low-grade orogenic metamorphic conditions. The original palaeogeographic location and the emplacement mechanisms for the Balagne ophiolites are still a matter of debate and different interpretations for its history have been proposed. The deformation features of the Balagne ophiolites are outlined in order to provide constraints on their history in the framework of the geodynamic evolution of Alpine Corsica. The deformation history reconstructed for the Balagne Nappe includes five different deformation phases, from D1 to D5. The D1 phase was connected with the latest Cretaceous/Palaeocene accretion into the accretionary wedge related to an east-dipping subduction zone followed by a Late Eocene D2 phase related to emplacement onto the Europe/Corsica continental margin. The subsequent D3 phase was characterized by sinistral strike-slip faults and related deformations of Late Eocene-Early Oligocene age. The D4 and D5 phases were developed during the Early Oligocene-Late Miocene extensional processes connected with the collapse of the Alpine belt.

The architecture of an incipient oceanic basin: a tentative reconstruction of the Jurassic Liguria-Piemonte basin along the Northern Apennines–Alpine Corsica transect

“…According to its stratigraphy (Durand-Delga et al 1997), the ophiolite sequence comes from an area of the Liguria-Piemonte basin close to the Corsica continental margin. This interpretation fits very well with the reconstruction of the deformation history proposed by Marroni and Pandolfi (2003) that strongly supports an original location of the Balagne nappe close to the Corsica continental margin.…”

“…Ophiolite units also deformed under very low-grade metamorphic units occur, mainly in the Balagne Nappe. They form the Nappes Supé -rieures, representing the top of the nappe pile of Alpine Corsica (e.g., Nardi et al 1978;Marroni and Pandolfi 2003). Both, Nappes supé rieures and Schistes Lustré s complex, are thrust onto the tectonic units derived from the Corsica continental margin (Caporalino-S.Angelo nappe, Corte units, Palasca unit and Tenda massif) consisting of slices of Mesozoic to Middle Eocene sedimentary cover associated with remnants of crystalline basement.…”

“…During intraoceanic convergence, the ophiolite sequences of Alpine Corsica were deformed and metamorphosed through underthrusting and subsequent transfer to the accretionary wedge connected with the subduction zone (e.g., Warburton 1986 and references therein). Weakly metamorphosed but strongly deformed oceanic sequences occur in both the Northern Apennines and Corsica, mainly resulting from shallow level accretion (e.g., Marroni and Pandolfi 1996;Marroni and Pandolfi 2003). In the Early Tertiary, intraoceanic subduction was followed by continental collision leading to a thick orogenic wedge.…”

Orogenic processes and the Corsica/Apennines geodynamic evolution: insights from Taiwan

“…(4) The upper-Nappe system also called Nappe Superiore includes the Balagne, Nebbio, and Macinaggio units. It is formed by ophiolitic as well as continentalderived rocks mainly associated with Late-Cretaceous siliciclastic and calcareous-marly flysch deposits (Nardi 1968;Durand-Delga 1984;Dallan and Nardi 1984;Marroni and Pandolfi 2003). The units are characterized by low-grade assemblages (prehnite/ pumpellyite in basic rocks) and a geometrically high position in the nappe stack.…”

Deformation history of the eclogite‐ and jadeitite‐bearing mélange from North Motagua Fault Zone, Guatemala: insights in the processes of a fossil subduction channel

“…This finding and the ENE-WSW trend of the D4 folds indicate the extension was at a high-angle to the plate boundary, different from that stated for the D2 phase. This type of deformation is recognized in several orogenic belts as in the Alps (Ratschbacher et al 1989;Froitzheim, 1992;Wheeler and Butler 1994), in Corsica (Malavieille et al 1998;Marroni and Pandolfi 2003) and also in the Caribbean area (Ellero et al 2007). Many examples of fragments of oceanic lithosphere exhumed after their underplating at depth are characterized by extensional tectonics only at very shallow structural levels in the final stage of the exhumation history, as described, for instance, in the Maksyutov Complex from southern Urals, Russia by Hetzel et al (1998), in the Schistes Lustres from Corsica, France (Levi et al 2007), in the Tacagua unit from Cordillera de la Costa, Venezuela (Ellero et al 2007) and in the Samanà peninsula from the Dominican Republic (Goncalvez et al 2000).…”