Vol.:(0123456789) 1 3
International Journal of Earth Sciences
https://doi.org/10.1007/s00531-020-01898-6
ORIGINAL PAPER
Timing and kinematics of fow in a transpressive dextral shear zone,
Maures Massif (Southern France)
Matteo Simonetti
1
· Rodolfo Carosi
1
· Chiara Montomoli
1,2
· Michel Corsini
3
· Alessandro Petroccia
1
·
John M. Cottle
4
· Salvatore Iaccarino
1
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 frst 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 fow, fnite 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 frst time, the vorticity of the fow, fnite 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
The Variscan belt is the result of the Lower Carbonif-
erous continent–continent collision between Lauren-
tia–Baltica and Gondwana (Arthaud and Matte 1977;
Burg and Matte 1978; Tollmann 1982; Matte 1986;
Franke 1989). This continental collision likely involved
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.
* Rodolfo Carosi
rodolfo.carosi@unito.it
Matteo Simonetti
matteo.simonetti@unito.it
Chiara Montomoli
chiara.montomoli@unito.it
Michel Corsini
corsini@unice.fr
Alessandro Petroccia
alessandro.petroccia@edu.unito.it
John M. Cottle
cottle@geol.ucsb.edu
Salvatore Iaccarino
salvatore.iaccarino@unito.it
1
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