Alpine deformation on Naxos (Greece)

Abstract

A detailed structural study of Naxos (Attic-Cycladic massif, Greece) reveals two major deformation events. The first one is associated with large scale thrusting and high-pressure-low-temperature metamorphism during an early Alpine subduction episode. The second event occurred during continental extension and the associated development of localized thermal domes, where lower crustal rocks were brought into contact with upper crustal units along a major shallow dipping shear zone. We agree with a model of Naxos as a Cordilleran type Metamorphic Core Complex. However, our observations show that the sense of shear was ‘upper plate moving North’ during the second event, calling for a reinterpretation of existing tectonic models of the Cyclades.

Kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern Mediterranean region since the late Cretaceous

“…5-8.5 kbar, 500-700°C) and associated migmatites also developed in the central Cyclades, such as in the Naxos, Paros, Mykonos and Ikaria islands [Jansen and Schuiling, 1976;Lister et al, 1984;Urai et al, 1990;Keay et al, 2001;Vanderhaeghe, 2004;Duchêne et al, 2006;Kruckenberg et al, 2011;Beaudoin et al, 2015;Laurent et al, 2015]. Exhumation of these rocks as MCCs was accommodated during the Oligocene-Miocene by several ductile-brittle detachment systems (figures 4 and 6) comprising the top-to-the NE North Cycladic Detachment System (NCDS) [Faure et al, 1991;Lee and Lister, 1992;Gautier and Brun, 1994;Mehl et al, 2005Mehl et al, , 2007Brichau et al, 2007Brichau et al, , 2008Jolivet et al, 2010a], the top-to-the N Naxos/Paros Extensional Fault System (NPEFS) [Urai et al, 1990;Gautier et al, 1993;Brichau et al, 2006;Seward et al, 2009;Bargnesi et al, 2013] and the top-to-the SW West Cycladic Detachment System (WCDS) [Grasemann and Petrakakis, 2007;Brichau et al, 2010;Iglseder et al, 2011;Grasemann et al, 2012]. The minimum offset of these extensional structures is estimated at 60-100 km for the NCDS [Jolivet et al, 2004a;Brichau et al, 2008] and ~50 km for the NPEFS (figure 3) [Brichau et al, 2006].…”

“…In the Cyclades, the NCDS accommodated this exhumation since the Oligocene (figures 9 and 11) [Faure et al, 1991;Lee and Lister, 1992;Brichau et al, 2007Brichau et al, , 2008Jolivet et al, 2010a] while the NPEFS and the WCDS became active in the early Miocene [Urai et al, 1990;Gautier et al, 1993;Vanderhaeghe, 2004;Brichau et al, 2006;Seward et al, 2009;Iglseder et al, 2011;Grasemann et al, 2012]. Syntectonic sediments started to be deposited in the hanging wall of these extensional structures [Photiades, 2002;Sánchez-Gómez et al, 2002;Kuhlemann et al, 2004;Lecomte et al, 2010;Laurent et al, 2015].…”

“…In the Cyclades, for example, three large-scale structures with wellconstrained kinematics and timing have been considered: the NCDS cropping out in the Tinos, Mykonos and Ikaria islands [Lee and Lister, 1992;Gautier and Brun, 1994;Mehl et al, 2005;Brichau et al, 2007;Jolivet et al, 2010a;Lecomte et al, 2010], the NPEFS cropping out in the Naxos and Paros islands [Lister et al, 1984;Urai et al, 1990;Gautier et al, 1993;Seward et al, 2009;Bargnesi et al, 2013] and the WCDS cropping out in the Serifos island (figures 3 and 6) [Grasemann and Petrakakis, 2007;Brichau et al, 2010;Iglseder et al, 2011; A C C E P T E D M A N U S C R I P T…”

Multiphase Boudinage: a case study of Amphibolites in Marble in the Naxos Migmatite core

“…Situated in the footwall of the North Cycladic detachment system and exposing a rich variety in lithologies and metamorphic facies, Naxos has been the subject of multiple studies, and plays a key role for the understanding of the tectonic history of the Aegean domain (Buick, 1991;Gautier et al, 1993;Jansen, 1973;Jansen and Schuiling, 1976;Jolivet et al, 1994Jolivet et al, , 2004Jolivet et al, , 20 2010; Keay et al, 2001;Urai et al, 1990).…”

“…The present-day metamorphic facies distribution is the result of at least three distinct metamorphic phases associated with Alpine deformation (Urai et al, 1990). The first metamorphic event at high pressure-low-temperature conditions is 25 associated with top to the south shearing in the Hellenic subduction zone (D1), and formation of the Hellenides at approximately 50 Ma (Andriessen et al, 1979;Dürr et al, 1978;Urai et al, 1990;Wijbrans and McDougall, 1988).…”