39 Ar/ 40 Ar dating of glaucophanes and phengites in southern Euboa (Greece); geodynamic implications

Maluski, H.; Vergély, P.; Bavay, D.; Bavay, P.; Katsikatsos, G.

doi:10.2113/gssgfbull.s7-xxiii.5.469

Cited by 48 publications

(43 citation statements)

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“…An Eocene sedimentary age for the Almyropotamos Unit is proven by fossils found at the top of the marble sequence (Dubois & Bignot, 1979), whereas metamorphic ages for the South Evia Blueschist Belt are based on radiometric dating of glaucophane-bearing samples taken from the Styra and Ochi formations (Maluski et al 1981;Klein-Helmkamp, Reinecke & Stöckhert, 1995). Age determinations of metamorphism of the Tsaki Formation and the Almyropotamos flysch are unavailable.…”

Section: Discussionmentioning

confidence: 99%

“…In south Evia, Maluski et al (1981) found 45-55 Ma to be the age associated with the main highpressure metamorphic event, using the 40 Ar/ 39 Ar dating method on phengite and glaucophane. A K-Ar age of~37 Ma was derived from phengite by Klein-Helmkamp, Reinecke & Stöckhert (1995) Katsikatsos et al 1986), showing the three tectonic units of Evia, Attica and the northern Cyclades.…”

Section: A Backgroundmentioning

confidence: 99%

“…Most workers (e.g. Maluski et al 1981;Katsikatsos et al 1986;Jacobshagen, 1986) group it with the structurally higher Ochi Formation. In contrast, Chenevart & Katsikatsos (1967) correlate it with the Almyropotamos flysch, and in the geological map of Evia (Katsikatsos, 1991a,b) it is distinguished as a discrete formation.…”

Section: B Tectonostratigraphy Of the Almyropotamos Areamentioning

confidence: 99%

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Alpine high-pressure metamorphism at the Almyropotamos window (southern Evia, Greece)

2000

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The Alpine orogenic belt of the Hellenides has been strongly reworked by ductile and brittle extensional tectonics. Extensional structures have affected the central Aegean region and obliterated much of the original orogenic architecture since at least early Miocene times. In the area of Almyropotamos (on the island of Evia, flanking the western part of the Aegean) a unique remnant compressional nappe stack involving Tertiary metamorphic rocks has been preserved. This nappe sequence comprises a high-pressure rock unit on top of a lower grade unit. The upper unit (South Evia Blueschist Belt) is thought to be the westward continuation of the Cycladic blueschist belt metamorphosed at high-pressure conditions during Late Cretaceous-Eocene times. The underlying unit (the Almyropotamos Unit) is a continental margin sequence covered by a flysch and containing Lutetian nummulites, indicating that this unit accumulated sediments until at least late Eocene times.In the present study we analyse the petrology of the Almyropotamos nappe stack and define the P-T conditions of each of the different rock units exposed there. The presence of glaucophane, lawsonite rimmed by epidote, and jadeite (70 mol. %) suggest that peak P-T conditions in the South Evia Blueschist Belt reached approximately 10-12 kbar and 350-450°C. Unlike previous studies, which estimated that the underlying Almyropotamos Unit reached only greenschist-facies conditions, glaucophane relics and Si-rich phengites were found by us in this unit. These indicate that high-pressure metamorphism and crustal thickening in this part of the Aegean lasted until at least the late Eocene or early Oligocene. We note that in this respect the architecture of southern Evia resembles that of northern Greece (Olympos, Ossa). Our structural data indicate that rock units in the Almyropotamos area record different folding phases, with the South Evia Blueschist Belt having a more complex fold history than the underlying Almyropotamos Unit. The entire nappe stack shares large-scale folds which are E-W trending, and locally overturned-to-the-south, and which may represent (at present coordinates) N-S contraction and nappe transport.

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Section: Discussionmentioning

confidence: 99%

Section: A Backgroundmentioning

confidence: 99%

Section: B Tectonostratigraphy Of the Almyropotamos Areamentioning

confidence: 99%

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Alpine high-pressure metamorphism at the Almyropotamos window (southern Evia, Greece)

2000

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“…Since then, many researchers (Argyriadis et al 1976, Aubouin 1977, Dubois & Bignot 1979, Gerneut 1971, Katsikatsos 1971, Katsikatsos et al 1986, Lensky et al 1997, Maluski et al 1981, Papanikolaou 1987, Shaked et al 2000 adopt that subdivision fulfilling and refining the details: Paleocene's metaflysch over Almyropotamo's marbles, "blue schists" over the other units, adopting also new nomenclature (see Geological Map of IGME). However, this first subdivision contained "errors of youth" that are retracted by the newer observations of the author and thus today, the dominate aspect is that exists only three units which are multiple folded: the Almyropotamos unit at the bottom and the other two units, Styra and Tsakaioi-Ochi, at the top of succession.…”

Section: Southern Eviamentioning

confidence: 99%

A New Interpretation of the Structure of Internal Hellenides

Argyriadis¹,

Midoun

Ntontos³

2017

geosociety

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“…The findings of Baroz et al (1987) demonstrate clearly that intensive compressional tectonic activity occurred during the Cretaceous. Based on tectonostratigraphic arguments and radiometric age determinations, pre-Tertiary ages for the blueschist facies metamorphism have been suggested for southern Euboea (Bavay et al 1980;Maluski et al 1981) and for the Pelion peninsula (Jacobshagen and Wallbrecher 1984). For the Olympos-Ossa region, Schermer et al (1990) suggested a Mid-Cretaceous (100-98 Ma) event of transitional greenschist-to-blueschist facies metamorphism that culminated in a two-stage Tertiary blueschist facies metamorphism during the Paleocene (61-53 Ma) and the Middle to Late Eocene .…”

Section: Introductionmentioning

confidence: 99%

Detrital blue amphiboles from the western Othrys Mountain and their relationship to the blueschist terrains of the Hellenides (Greece)

Faupl

Petrakakis

Migiros

et al. 2001

Int J Earth Sci (Geol Rundsch)

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In contrast to blue amphiboles of the Ossa and Olympos tectonic windows in Thessaly, detrital blue amphiboles in Paleocene flysch deposits in the western Othrys Mountain (Pelagonian Zone s.l.) are chemically comparable with blue amphiboles from the Cyclades. For the detrital material, therefore, a source with "Cycladic" chemical affinities is assumed. The occurrence of these detrital minerals is in line with a Cretaceous onset of blueschist facies metamorphism in parts of the Hellenides, especially in the Cycladic belt. This was in response to Cretaceous subduction of the Pindos oceanic plate along the external margin of the Pelagonian micro-continent. Blueschist complexes were exhumed latest in the Paleocene when the terrigenous flysch sedimentation started in the Pelagonian and Pindos zones.

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39 Ar/ 40 Ar dating of glaucophanes and phengites in southern Euboa (Greece); geodynamic implications

Cited by 48 publications

References 0 publications

Alpine high-pressure metamorphism at the Almyropotamos window (southern Evia, Greece)

Alpine high-pressure metamorphism at the Almyropotamos window (southern Evia, Greece)

A New Interpretation of the Structure of Internal Hellenides

Detrital blue amphiboles from the western Othrys Mountain and their relationship to the blueschist terrains of the Hellenides (Greece)

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