Timing and kinematics of flow in a transpressive dextral shear zone, Maures Massif (Southern France)
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ORIGINAL PAPER
Timing and kinematics of flow in a transpressive dextral shear zone, Maures Massif (Southern France) Matteo Simonetti1 · Rodolfo Carosi1 · Chiara Montomoli1,2 · Michel Corsini3 · Alessandro Petroccia1 · John M. Cottle4 · Salvatore Iaccarino1 Received: 28 February 2020 / Accepted: 22 June 2020 © Geologische Vereinigung e.V. (GV) 2020
Abstract The Maures–Tanneron Massif and the Corsica–Sardinia Block are two segments of the southern European Variscan belt that separated during the Late Oligocene–Miocene due to the opening of the Western Mediterranean basin. Correlation between the two regions, based mainly on petrologic similarities, is still debated. However, there are no detailed structural and petrochronological constraints on their potential relationships. In northern Sardinia there is well-documented evidence for a dextral transpressive shear zone that initiated after the first stage of frontal collision. In the Maures–Tanneron Massif, despite recognition of an important episode of transpressive deformation, it is still unclear which structures were active during this tectonic regime. We investigate in detail the kinematic of flow, finite strain and the timing of the deformation of the Cavalaire “Fault” (CF), a major ductile shear zone in the Maures–Tanneron Massif. In contrast to previous models, we argue that the CF is a transpressive shear zone characterized by a prevalent component of pure shear, while in-situ monazite geochronology reveals that the CF is initiated at ~ 323 Ma. The new data presented here, based on a multidisciplinary approach document, for the first time, the vorticity of the flow, finite strain and timing of this sector of the East Variscan Shear Zone, a regional-scale shear zone that characterized the Southern European Variscan belt during the late Carboniferous. Keywords Maures–Tanneron massif · Transpression · East variscan shear zone · Sardinian basement · Vorticity · Monazite petrochronology
Introduction
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00531-020-01898-6) contains supplementary material, which is available to authorized users.
The Variscan belt is the result of the Lower Carboniferous continent–continent collision between Laurentia–Baltica and Gondwana (Arthaud and Matte 1977; Burg and Matte 1978; Tollmann 1982; Matte 1986; Franke 1989). This continental collision likely involved
* Rodolfo Carosi [email protected]
Salvatore Iaccarino [email protected]
Matteo Simonetti [email protected]
1
Chiara Montomoli [email protected]
Dipartimento Di Scienze Della Terra, Università Degli Studi Di Torino, via V. Caluso 35, 10125 Torino, Italy
2
IGG-CNR PISA, via Moruzzi 1, Pisa, Italy
3
Géoazur, Université Côte D’Azur, 250, rue A. Einstein, 06560 Valbonne, France
4
Department of Earth Science, Lagoon Rd, Santa Barbara, CA 93106, USA
Michel Corsini [email protected] Alessandro Petroccia [email protected] John M. Cottle cottle@g
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