Penrose Conference - Extending a Continent - Naxos Field Guide

Vanderhaeghe, Olivier; Hibsch, C.; Siebenaller, Luc; Duchêne, Stéphanie; Blanquat, M. de St; Kruckenberg, Seth C.; Fotiadis, A.; Martin, L. A.

doi:10.3809/jvirtex.2007.00175

Cited by 19 publications

(17 citation statements)

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“…At the scale of the Cyclades, the increase in temperature recorded by the lowest structural level of the ACMC is potentially induced by the combined effects of (i) an increased radioactive heat production in the thickened crust, and (ii) an increased basal heat flux caused by asthenospheric upwelling in response to slab retreat, and (iii) heat advection induced by the emplacement of mantle-derived magmas (Vanderhaeghe et al, 2007). This increase in temperature reaches its climax in Naxos Island as suggested by the presence of migmatites (Duchêne et al, 2006;Martin et al, 2008;Kruckenberg et al, 2011).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

CO 2 flow during orogenic gravitational collapse: Syntectonic decarbonation and fluid mixing at the ductile-brittle transition (Lavrion, Greece)

et al. 2017

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Section: Accepted Manuscriptmentioning

confidence: 99%

CO 2 flow during orogenic gravitational collapse: Syntectonic decarbonation and fluid mixing at the ductile-brittle transition (Lavrion, Greece)

et al. 2017

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“…Across the entire exposed metamorphic dome, both flanking detachment fault planes discontinuously crop out due to the late brittle reworking of kilometric‐scale steep, normal to transtensional faults (Figure e; Gautier et al, ; Jansen, ; Siebenaller, ; Vanderhaeghe, Hibsch, Siebenaller, Duchêne, Kruckenberg, et al, ). The Naxos detachment fault can only be traced at the northwestern flank of the migmatitic dome where it tectonically dismembered the presumed CCB.…”

Section: Detachment Systems and Synextensional Intrusions Within The mentioning

confidence: 99%

Synextensional Granitoids and Detachment Systems Within Cycladic Metamorphic Core Complexes (Aegean Sea, Greece): Toward a Regional Tectonomagmatic Model

et al. 2018

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Within deforming continental regions where metamorphic core complexes (MCCs) and synextensional granitoids are closely associated, deciphering the link between detachment faulting and magmatism often remains complex as (1) the rheological weakness of magma may stimulate mechanisms of strain localization, and conversely, (2) tectonic processes may open/close drains where magmas can intrude.Here we tackle this issue by focusing on the Cyclades with the comparison of five granitoid-cored MCCs (Tinos, Mykonos, Ikaria, Naxos, and Serifos) and their flanking detachment systems. In this region, granitoids were emplaced into the middle/upper crust over a relatively short time period (15-9 Ma), while metamorphic domes were largely exhumed after more than 10 Myr of extension. None of those intrusions thereby proves to be a real candidate for the genesis of MCCs but would rather be a consequence of a warmer regime during lithospheric thinning. However, all collected structural and kinematic data converge toward a regional scheme in which magmatic activity played a more pivotal role than previously postulated. Indeed, late evolution stages of MCCs were dynamically impacted by intrusions along which local and transient heterogeneities of the mechanical strength occurred, interfering with the sequential development of detachments. During their tectonically controlled emplacement, magmatic products intruded already formed detachments at depth, locally inhibiting their activity, associated with a contemporaneous upward migration of extensional deformation that tended to localize through time within intrusion roofs along rheological discontinuities. The newly formed detachments are expressed within granitoids through a continuum of deformation from comagmatic to ductile conditions, followed by cataclasis along detachments.Plain Language Summary Tectonics intensely deform continents forming mountains when the crust is thickened or low-standing regions where the sea can invade in the case of extension. Extension is less spectacular as deformation is hidden below sea level, but it involves intense deformations that can be studied when the deep crustal levels are exhumed below extensional faults with low-angle detachments. The portions of exhumed crust reveal deep deformation processes associated with emplacement of magmatic rocks because extension is coeval with heat advection toward the surface. One long pending question is whether or not the evolution of these detachments is influenced by growing granites. Based on a detailed field study of the deformation of five such examples in the Cycladic Archipelago, we show that the granites modify the evolution of the low-angle extensional faults leading to the sequential development and upward migration in the crust of a series of detachments through time. Granites indeed influence the evolution of detachments because they heat the crust in their vicinity and thus modify its mechanical resistance and introduce a mechanical heterogeneity during growth and cooling as the magma is intrinsica...

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“…1b–d) (Jansen, 1973; Jansen & Schuiling, 1976; Buick, 1991a,b; Gautier et al. , 1993; Vanderhaeghe, 2004; Vanderhaeghe et al. , 2007; Kruckenberg et al.…”

Section: Geology Of Naxos Islandmentioning

confidence: 99%

“…The island of Naxos displays the most complete structural cross-section of the Cyclades with metamorphosed ante-Mesozoic rocks and Cenozoic granitoids juxtaposed to Cenozoic sediments or weakly metamorphosed rocks along a low-angle detachment ( Fig. 1b-d) (Jansen, 1973;Jansen & Schuiling, 1976;Buick, 1991a,b;Gautier et al, 1993;Vanderhaeghe, 2004;Vanderhaeghe et al, 2007;Kruckenberg et al, 2010Kruckenberg et al, , 2011. Three tectono-metamorphic units are distinguished.…”

Section: Geology Of Naxos Islandmentioning

confidence: 99%

Fluid record of rock exhumation across the brittle–ductile transition during formation of a Metamorphic Core Complex (Naxos Island, Cyclades, Greece)

Siebenaller¹,

Boiron²,

Vanderhaeghe³

et al. 2012

Journal Metamorphic Geology

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Fluid inclusions trapped in quartz veins hosted by a leucogneiss from the southern part of the Naxos Metamorphic Core Complex (Attic‐Cycladic‐Massif, Greece) were studied to determine the evolution of the fluid record of metamorphic rocks during their exhumation across the ductile/brittle transition. Three sets of quartz veins (V‐M2, V‐BD & V‐B) are distinguished. The V‐M2 and V‐BD are totally or, respectively, partially transposed into the foliation of the leucogneiss. They formed by hydrofracturing alternating with ductile deformation accommodated by crystal‐plastic deformation. The V‐B is discordant to the foliation and formed by fracturing during exhumation without subsequent ductile transposition. Fluids trapped during crystal–plastic deformation comprise two very distinct fluid types, namely a CO2‐rich fluid and a high‐salinity brine, that are interpreted to represent immiscible fluids generated from metamorphic reactions and the crystallization of magmas respectively. They were initially trapped at ∼625 °C and 400 MPa and then remobilized during subsequent ductile deformation resulting in various degrees of mixing of the two end‐members with later trapping conditions of ∼350 °C and 140 MPa. In contrast, brittle microcracks contain aqueous fluids trapped at 250 °C and 80 MPa. All veins display a similar δ13C pointing to carbon that was trapped at depth and then preserved in the fluid inclusions throughout the exhumation history. In contrast, the δD signature is marked by a drastic difference between (i) V‐M2 and V‐BD veins that are dominated by carbonic, aqueous‐carbonic and high‐salinity fluids of metamorphic and magmatic origin characterized by δD between −56‰ and −66‰, and (ii) V‐B veins that are dominated by aqueous fluids of meteoric origin characterized by δD between −40‰ and −46‰. The retrograde P–T pathway implies that the brittle/ductile transition separates two structurally, chemically and thermally distinct fluid reservoirs, namely (i) the ductile crust into which fluids originating from crystallizing magmas and fluids in equilibrium with metamorphic rocks circulate through a geothermal gradient of 30 °C km−1 at lithostatic pressure, and (ii) the brittle upper crust through which meteoric fluids percolate through a high geothermal gradient of 55 °C km−1 at hydrostatic pressure.

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Penrose Conference - Extending a Continent - Naxos Field Guide

Cited by 19 publications

References 0 publications

CO 2 flow during orogenic gravitational collapse: Syntectonic decarbonation and fluid mixing at the ductile-brittle transition (Lavrion, Greece)

CO 2 flow during orogenic gravitational collapse: Syntectonic decarbonation and fluid mixing at the ductile-brittle transition (Lavrion, Greece)

Synextensional Granitoids and Detachment Systems Within Cycladic Metamorphic Core Complexes (Aegean Sea, Greece): Toward a Regional Tectonomagmatic Model

Fluid record of rock exhumation across the brittle–ductile transition during formation of a Metamorphic Core Complex (Naxos Island, Cyclades, Greece)

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