Cenozoic tectonic evolution of Naxos Island through a multi-faceted approach of fission-track analysis

Abstract

New zircon and apatite fission-track ages obtained on samples from all lithotectonic units exposed on Naxos Island are presented. Zircon ages of the exhumed metamorphic rocks range from 25.2 to 9.3 Ma and from 13.0 to 6.4 Ma for apatite. Zircon track-length analysis distinguishes partial overprinting of an earlier event (M1) in the south. Northwards no overprint is seen and the ages there represent rapid exhumation since c. 12 Ma. Both zircon and apatite ages are slightly older toward the north of the island probably due to variation of the geotherm in the proximity of the fault.Zircon fission-track ages of the granodiorite range from 13.7 to 12.2 Ma are statistically identical to previously determined U–Pb ages. Apatite fission-track ages however, yield a younging trend from south to north from 12.9 to 9.0 Ma. This could be due to differential depth of emplacement and/or to differential exhumation during tectonic unroofing by a top-to-the north detachment.Fission-track ages on detrital grains in Lower Miocene sediments indicate a source not identified within the present outcropping rocks of Naxos. Ages on boulders and grains in the Middle to Upper Miocene sediments point to rapid erosion until about 8.5–7 Ma.

Multiphase boudinage: a case study of amphibolites in marble in the Naxos migmatite core

“…These ages may be interpreted either as early intrusion, during oceanization of the Aegean, or as late emplacement during large-scale extension (Bolhar et al, 2016). Zircon and apatite fission track data from all tectonic units exposed on Naxos as well as UPb ages show a consistent cooling and exhumation scenario: cooling started at ∼ 25 Ma, and continued until ∼ 8 Ma (Seward et al, 2009;Brichau et al, 2006;John and Howard, 1995;Cao et al, 2017). Structures in the central migmatite dome show several synmigmatic subdomes (Vanderhaeghe, 2004) (Fig.…”

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

“…These ages may be interpreted either as early intrusion, during ocenazitation of the Aegean, or as late emplacement during largescale extension (Bolhar et al 2016). Zircon and apatite fission track data from all tectonic units exposed on Naxos as well as U-Pb ages show a consistent cooling and exhumation scenario: cooling started at ~25 Ma, and continued until ~ 8 Ma 5 (Seward et al 2009, Brichau et al, 2006, John and Howard, 1995.…”