The collisional Variscan (Early Carboniferous) evolution of the greenschist facies metamorphic basement of Sardinia is characterized by three deformation phases and two 90° reorientations of shortening direction. During the first phase of deformation N-S shortening occurred, with south-facing isoclinal folding, south-directed nappe emplacement and mylonitization in central and southeastern Sardinia, and large-scale E-W striking upright folds in southwestern Sardinia. Emplacement of the Barbagia, Meana Sardo, Gerrei and Riu Gruppa units took place during this event. This deformation phase was followed by E-W shortening, with W-directed emplacement of the Sarrabus and Arburese units along the Villasalto thrust and upright to E-dipping large-scale N-S striking upright folds in southwestern Sardinia. During the third deformation event, the shortening direction again rotated 90°, and N-S shortening produced kilometer-scale antiforms and synforms, the most prominent features in the metamorphic basement of Sardinia. The limbs of the kilometer-scale antiforms and synforms are vertically shortened during gravitational collapse, with contemporaneous faulting and conjugate shear zone development. Presence of large-scale E-W oriented antiforms was therefore critical for the formation of late Variscan extensional features, such as E-W striking, low-angle normal faulting. © 2001 Elsevier Science B.V. All rights reserved.

Conti, P., Carmignani, L., Funedda, A. (2001). Change of nappe transport direction during the Variscan collisional evolution of central-southern Sardinia (Italy). TECTONOPHYSICS, 332(1-2), 255-273 [10.1016/S0040-1951(00)00260-2].

Change of nappe transport direction during the Variscan collisional evolution of central-southern Sardinia (Italy)

Conti, P.;Carmignani, L.;
2001-01-01

Abstract

The collisional Variscan (Early Carboniferous) evolution of the greenschist facies metamorphic basement of Sardinia is characterized by three deformation phases and two 90° reorientations of shortening direction. During the first phase of deformation N-S shortening occurred, with south-facing isoclinal folding, south-directed nappe emplacement and mylonitization in central and southeastern Sardinia, and large-scale E-W striking upright folds in southwestern Sardinia. Emplacement of the Barbagia, Meana Sardo, Gerrei and Riu Gruppa units took place during this event. This deformation phase was followed by E-W shortening, with W-directed emplacement of the Sarrabus and Arburese units along the Villasalto thrust and upright to E-dipping large-scale N-S striking upright folds in southwestern Sardinia. During the third deformation event, the shortening direction again rotated 90°, and N-S shortening produced kilometer-scale antiforms and synforms, the most prominent features in the metamorphic basement of Sardinia. The limbs of the kilometer-scale antiforms and synforms are vertically shortened during gravitational collapse, with contemporaneous faulting and conjugate shear zone development. Presence of large-scale E-W oriented antiforms was therefore critical for the formation of late Variscan extensional features, such as E-W striking, low-angle normal faulting. © 2001 Elsevier Science B.V. All rights reserved.
2001
Conti, P., Carmignani, L., Funedda, A. (2001). Change of nappe transport direction during the Variscan collisional evolution of central-southern Sardinia (Italy). TECTONOPHYSICS, 332(1-2), 255-273 [10.1016/S0040-1951(00)00260-2].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/22920
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