The three metamorphic belts of the Hellenides: a review and a kinematic interpretation

Abstract

New results obtained in the three metamorphic belts of the Hellenides suggest that each belt has a different structure, geotectonic setting and evolution. The external metamorphic belt of Peloponnesus-Crete has probably resulted from nappe movement in the vicinity of an evolving island arc system. The blueschists occurring within this external belt are allochthonous and have been transported with other nappes over the external carbonate platform of the Pre-Apulian-Plattenkalk-Ionian-Tripolitza-Almyropotamos Units. This implies that there was only one true blueschist domain, initiated in the Cycladic area during ?Early Eocene. The kinematic interpretation is based on the distinction of a-and b-structures and on the nature of the shear zones between the different domains, especially that between the metamorphic Hellenides below and the non-metamorphic Hellenides above. The existence of the probably Lower Palaeozoic meta-sedimentary sequence of Kastoria in the northern Pelagonian zone indicates that the overlying, ophiolite-bearing Almopias unit has been derived from within the Hercynian domain. The Kastoria sedimentary sequence, the ophiolites of Vertiskos and the carbonate platform of Pangeon are considered to be most likely elements of a probable Hercynian orogeny.

Stratigraphy and geological structure of the Lavrion area (Attica, Greece)

“…"Phyllite" nappe: The metamorphic conditions of the "phyllite" nappe (Eocene blueschist and Miocene retrogressive greenschist facies) are typical of the median metamorphic belt of the Hellenides, largely expressed in the Attic-Cycladic Metamorphic Complex (Altherr et al, 1982;Papanikolaou, 1984). According to various authors, the Cycladic Blueschist unit would be originated in the Pindos basin (e.g.…”

“…Indeed, some equivalent non-metamorphic calcareous tectonic remnants associated with ophiolites constitute the Upper non-metamorphic tectonic unit within the Attic-Cycladic Metamorphic Complex (Dörr et al, 1978;Papanikolaou, 1984), as well as the post-flysch nappes of the Pelagonian s.l domain. In conclusion, the upper unit could be the upper part of a non-metamorphic Pelagonian nappe.…”

“…The Lavrion area (or Lavreotiki peninsula) constitutes the northwestern part of the Attic-Cycladic Meta morphic Complex; it also belongs to the Median Metamorphic Belt of the Hellenides (Dórr et al, 1978;Papanikolaou, 1984) and is built up of various alpine tectonic units (Papanikolaou, 1984;Katsikatsos et al, 1986).…”

Morphotectonic analysis of Kozani Basin (Western Macedonia, Greece)

“…The alpine basement of the Kozani neotectonic basin (Figure 1) is geotectonically located in the medial tectonometamorphic zone (Papanikolaou, 1984;Papanikolaou, 1986;Papanikolaou et al, 2004), also known as Pelagonian geotectonic unit (Mountrakis, 1985). The geological formations that can be observed in the wider Kozani area are the following (Neotectonic Map of Greece, Kozani Sheet, Scale: 1:100 000, Mountrakis et al 1999):…”

A new occurrence of pyrophanite from the amphibolite-hosted skarn in Western Kimmeria, Xanthi, Northern Greece.

“…The Hellenides, part of the Alpine-Himalayan orogen, can be considered an accretionary orogen, where a late Precambrian to late Jurassic evolution was marked by the opening and closure of ocean basins and continental crust formation in the accompanying subduction zones (Papanikolaou 1984;Reischmann and Kostopoulos, 2007). A Permo-Carboniferous igneous event (known from the Pelagonian Zone, the Rhodope Massif and the Attico-Cycladic Zone) documents an active continental margin evolution in the Precambrian-Silurian basement of the Hellenides (Reischmann and Kostopoulos, 2007).…”