The area between the Golo and Tavignano valleys (Central Corsica) provides a good opportunity to study the relationships between the Hercynian Corsica, the Corte Slices (i.e. Lower Units) and the Schistes Lustrés Complex (Di Rosa et al., 2017). The Hercynian Corsica consists of a paleozoic basement (Roches Brunes Fm. intruded by Permo-Carboniferous monzogranites) covered by Mesozoic and Tertiary sedimentary successions. Despite the occurrence of several shear zones of Tertiary age, the Hercynian Corsica is considered a domain not involved in the Alpine Orogeny. The Corte Slices and the Schistes Lustrés Complex, that belong to the Alpine Corsica, are the remains of the oceanic crust and the European continental margin, both involved in the E-dipping oceanic and continental subduction (Late Cretaceous to Early Tertiary). The subduction was associated by an exhumation whose end is regarded as pre-Burdigalian in age (Malasoma & Marroni 2007). In the study area the Schistes Lustrés Complex is represented by metaserpentinites, metagabbros, metabasalts and calc-schists, whereas the Corte Slices consist of three tectonic units similar in their lithostratigraphy (i.e. Paleozoic basement covered by Mesozoic to Tertiary metasediments) but different in the metamorphic degree. The structural setting of the Alpine Units is characterized by a polyphased deformation history: within the Corte Slices, three phases are recognized at all the scale of observation (D1-D3). The D1 produces F1 sheath folds and a S1 foliation, almost completely transposed by the D2 phase, characterized by F2 isoclinal folds with a subvertical axial plane foliation, a S2 and a L2 stretching lineation. The D3 is associated to F3 folds with a subhorizontal axial plane foliation. A post-D3 brittle deformation phase is associated to the Central Corsica Shear Zone, a strike-slip faults system that cuts all the previous structures. The Schistes Lustrès Complex shows a higher grade of deformation, acquired within the accretionary wedge during the oceanic subduction. However, the Schistes Lustrès Complex is folded by the same structures of the D3 phase recognized in the Corte Slices, that deform the previous phases within the Schistes Lustrés Complex as well as the tectonic contacts between it and the continental units. The occurrence of the Schistes Lustrés Complex as slices sandwiched between the Corte Slices, suggests an interaction between these two groups during the coupling of the continental units, i.e. in a pre-D3 phase.

1:10,000 structural map of the Corte Slices in the area between Golo and Tavignano valleys (Central Corsica).

Di Rosa M.
Primo
;
Marroni M.
Co-primo
;
Pandolfi L.
Co-primo
2017

Abstract

The area between the Golo and Tavignano valleys (Central Corsica) provides a good opportunity to study the relationships between the Hercynian Corsica, the Corte Slices (i.e. Lower Units) and the Schistes Lustrés Complex (Di Rosa et al., 2017). The Hercynian Corsica consists of a paleozoic basement (Roches Brunes Fm. intruded by Permo-Carboniferous monzogranites) covered by Mesozoic and Tertiary sedimentary successions. Despite the occurrence of several shear zones of Tertiary age, the Hercynian Corsica is considered a domain not involved in the Alpine Orogeny. The Corte Slices and the Schistes Lustrés Complex, that belong to the Alpine Corsica, are the remains of the oceanic crust and the European continental margin, both involved in the E-dipping oceanic and continental subduction (Late Cretaceous to Early Tertiary). The subduction was associated by an exhumation whose end is regarded as pre-Burdigalian in age (Malasoma & Marroni 2007). In the study area the Schistes Lustrés Complex is represented by metaserpentinites, metagabbros, metabasalts and calc-schists, whereas the Corte Slices consist of three tectonic units similar in their lithostratigraphy (i.e. Paleozoic basement covered by Mesozoic to Tertiary metasediments) but different in the metamorphic degree. The structural setting of the Alpine Units is characterized by a polyphased deformation history: within the Corte Slices, three phases are recognized at all the scale of observation (D1-D3). The D1 produces F1 sheath folds and a S1 foliation, almost completely transposed by the D2 phase, characterized by F2 isoclinal folds with a subvertical axial plane foliation, a S2 and a L2 stretching lineation. The D3 is associated to F3 folds with a subhorizontal axial plane foliation. A post-D3 brittle deformation phase is associated to the Central Corsica Shear Zone, a strike-slip faults system that cuts all the previous structures. The Schistes Lustrès Complex shows a higher grade of deformation, acquired within the accretionary wedge during the oceanic subduction. However, the Schistes Lustrès Complex is folded by the same structures of the D3 phase recognized in the Corte Slices, that deform the previous phases within the Schistes Lustrés Complex as well as the tectonic contacts between it and the continental units. The occurrence of the Schistes Lustrés Complex as slices sandwiched between the Corte Slices, suggests an interaction between these two groups during the coupling of the continental units, i.e. in a pre-D3 phase.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/890386
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