The structural evolution of Kythnos Island (Cyclades, Greece) a reconnaissance

Keiter, Mark; Tomaschek, Frank; Ballhaus, Chris

doi:10.1127/1860-1804/2008/0159-0513

Cited by 6 publications

(8 citation statements)

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“…100°C at 15-25 Ma, as indicated by apatite fission-track data (Ring et al, 2009) implies that cataclastic deformation of calcite marbles in D 3 thrust zones should have occurred just before and/or during the early Miocene (Figure 15). NEdirected thrusting during late Oligocene/early Miocene greenschist-facies retrogression of the Cycladic blueschist unit rocks has also been reported in western Cyclades islands (Xypolias et al, 2003Keiter et al, 2008). Moreover, well-documented top-to-NE thrusting coeval with retrogression of HP-rocks of the Menderes cover (Bozkurt and Park, 1999;Rimmelé et al, 2003a) seems to be comparative with the D 2 thrust event on Amorgos, although an Eocene (?)…”

Section: Phasementioning

confidence: 88%

“…Specifically, the (W)NW-(E)SE compression driving transpressional deformation, which controls the formation of middle Miocene molassic basins, has been reported from Samos, Paros, Naxos, Mykonos, Syros, Tinos, Milos, Serifos and Ikaria islands (e.g. Angelier, 1977;Boronkay and Doutsos, 1994;Koukouvelas and Kokkalas, 2003;Keiter et al, 2004Keiter et al, , 2008Kokkalas et al, 2006). This regional-scale deformation phase is possibly related to the initiation of the Aegean arc v. chatzaras ET AL.…”

Section: Brittle Transpressional Deformation (Middle-late Miocene)mentioning

confidence: 99%

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Oligocene–Miocene thrusting in central Aegean: insights from the Cycladic island of Amorgos

et al. 2011

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In the central Aegean, the Cycladic island of Amorgos consists of two high-pressure (HP) units, the marble-rich Amorgos unit, which is correlated to the Mesozoic 'cover' sequence of the Menderes Massif, and the Cycladic Blueschist unit. New structural data show that the deformation history of the Amorgos HP-rocks was principally governed by early Oligocene (or late Eocene)-early Miocene ductile to brittle thrusting (D 1 -D 3 ) followed by middle-late Miocene oblique contractional movements (D 4 -D 5 ). The D 1 phase caused syn-blueschist-facies ductile thrusting of the Cycladic Blueschist unit over the Amorgos unit, with ambiguous kinematics. Progressive deformation under continuous NW-SE compression produced a sequence of imbricate NW-directed thrusts (D 2/3 ) characterized by a stratification of faultrelated rocks, with mylonitic zones (D 2 ) giving way downwards to cataclastic zones (D 3 ). Ductile D 2 thrusting synchronous to greenschistfacies retrogression, was accompanied by mega-sheath folding during constrictional and general shear deformation. Brittle D 3 thrusting was associated with NW-verging F 3 folds trending at a high-angle to the transport direction. Orthogonal contraction gave way to transpression during which the compression orientation changed from NW-SE (D 4 ) to NE-SW (D 5 ). Back-arc related NW-SE pure extension (D 6 ) seems to have been established in post-late Miocene times and related high-angle normal faulting affected HP-rocks only after they had already reached the uppermost crustal levels. Oligocene-early Miocene deformation history is interpreted to indicate syn-compressional exhumation of HP-rocks possibly in an extrusion wedge. In this case, Amorgos HP-rocks should have occupied the base of the extrusion wedge.

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Section: Phasementioning

confidence: 88%

Section: Brittle Transpressional Deformation (Middle-late Miocene)mentioning

confidence: 99%

Oligocene–Miocene thrusting in central Aegean: insights from the Cycladic island of Amorgos

et al. 2011

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“…In contrast, widespread top-to-the NE kinematics in the wedge's body and restricted top-to-the-SW shearing at the wedge's roof fit well with a NE directed extrusion. Opposite top-the-SW shearing coeval with greenschist facies retrogression has been observed at the upper structural levels of Cycladic Blueschists in western Cyclades (e.g., Kythnos, Kea; Figure 16a); note that the Uppermost unit is exposed in Kythnos [Keiter et al, 2008] and Kea [Iglseder et al, 2011].…”

Section: Exhumation Stagementioning

confidence: 92%

Subduction‐ and exhumation‐related structures in the Cycladic Blueschists: Insights from south Evia Island (Aegean region, Greece)

et al. 2012

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[1] Detailed geological mapping, structural investigation and amphibole chemistry analyses in southern Evia (Aegean Sea, Greece) allow us to place new constraints on the internal structural architecture and tectonic evolution of the Cycladic Blueschists. We show that the early deformation history was related to ESE directed thrusting resulting in the stacking of the Styra and Ochi nappes, which constitute the Cycladic Blueschist unit in Evia. These early thrust movements initiated just before and proceeded at peak conditions of the Eocene high-pressure metamorphism. Subsequent constrictional deformation gave rise to E-W trending upright folding accomplished at the early exhumation stage. The main ductile-stage exhumation occurred during a single deformation phase associated with the decompression of blueschist rocks from the stability field of crossite to that of actinolite. This phase was characterized by localization of ductile deformation into a series of major, tens of meters thick, ENE directed shear zones, which cut up-section in their transport direction and restack the early thrust and fold sequence, locally bringing the structurally lower Styra nappe over the higher Ochi nappe. It is suggested that these zones operated as thrusts rather than normal sense shear zones as has been previously argued and were possibly formed during the Oligocene ENE-ward extrusion of the blueschists. Brittle-ductile NE dipping normal faulting of post-early Miocene age was probably responsible for the final exhumation of rocks.Citation: Xypolias, P., I. Iliopoulos, V. Chatzaras, and S. Kokkalas (2012), Subduction-and exhumation-related structures in the Cycladic Blueschists:

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“…Relics of high-pressure metamorphism are manifested by glaucophane and pseudomorphs of jadeite and garnet (Schliestedt et al, 1994). Deformation under these conditions is dominated by complex refolded structures with dominantly NW-SE-trending fold axes and subhorizontal axial planes (Keiter et al, 2008). The stretching lineation (lm 1 ) generally trends WSW-ENE with a top-to-the-WSW shear sense (Fig.…”

Section: Kythnosmentioning

confidence: 93%

Miocene bivergent crustal extension in the Aegean: Evidence from the western Cyclades (Greece)

et al. 2012

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Current models for Miocene backarc extension of the Aegean region generally suggest that stretching was accommodated mainly by NEdipping low-angle normal faults with N to NE sense of shear. A crustal-scale low-angle normal fault system trending over a length of more than 200 km forms the North Cycladic detachment system, which records a NE-directed normal shear sense separating the Cycladic Blueschist unit in the footwall from the Upper Cycladic unit in the hanging wall. Based on new structural fi eld data, we propose the existence of another large-scale low-angle normal fault system, the West Cycladic detachment system, which is exposed on Kea, Kythnos, and Serifos, strikes over a length of at least 100 km, and has a possible extension to the SE, where the existence of a South Cycladic detachment system has been recently postulated. The West Cycladic detachment system shares many similarities with the North Cycladic detachment system, with the notable exception that the structure dips toward the SW with top-to-the-SSW kinematics. New 40 Ar/ 39 Ar and U-Th/He thermochronological data suggest that the West Cycladic detachment system accommodated extension throughout the Miocene. Since both the North and the West Cycladic detachment systems were active until the late Miocene but exhibit opposing shear sense, we propose that a large part of the stretching of the Aegean crust was accommodated by these two bivergent crustal-scale detachment systems.

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The structural evolution of Kythnos Island (Cyclades, Greece) a reconnaissance

Cited by 6 publications

References 0 publications

Oligocene–Miocene thrusting in central Aegean: insights from the Cycladic island of Amorgos

Oligocene–Miocene thrusting in central Aegean: insights from the Cycladic island of Amorgos

Subduction‐ and exhumation‐related structures in the Cycladic Blueschists: Insights from south Evia Island (Aegean region, Greece)

Miocene bivergent crustal extension in the Aegean: Evidence from the western Cyclades (Greece)

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