Correlation of the Hellenide nappes in the south-east Aegean and their tectonic reconstruction

Abstract

Summary The central Aegean nappe pile can be readily related to that of the mainland Hellenides and has the advantage that the deeper levels are well displayed, particularly in the Cyclades. The following units can be distinguished, from base to top: (1) The para-autochtonous Ida or Talea Ori Sequence , recognized in Crete, Kassos, Rhodes (Lindos sequence) and Amorgos is, in part, a neritic carbonate platform sequence. It can be correlated with the Ionian-Preapulian autochthon of the mainland and most probably with the Menderes sequence of western Anatolia, there exposed in a tectonic window. (2) The major Tripolitza Nappe , a carbonate platform sequence, with the Phyllite Nappe at its base, is well represented in the outer arc as well as in Astypaleia and Santorini. (3) The Pindos and Arvi Nappes of Crete, Rhodes and Tilos are the remnants of an ocean basin active from Upper Triassic to Late Cretaceous times. (4) The Cycladic Blueschist Unit exposed on Syros, Siphnos, Naxos and other islands, occupies a tectonic position similar to the Pindos Nappe. It is interpreted as the subducted margin of the European plate, while the Pindos Nappe, the abyssal plain of the Apulian plate, was obducted just before continental collision in the Late Eocene-Oligocene. (5) The Asteroussia Nappe , composed of high-grade metamorphic rocks yielding cooling ages around 75 Ma, is present in Crete and in the Cycladic islands of Syros, Nikouria, Denoussa and Keros. It is interpreted as the remnants of a Pelagonian basement nappe, eroded in Miocene times. In the external or outer belt it has been thrust on to the unmetamorphosed Pindos Nappe but in the Cyclades it rests on the Cycladic Blueschist unit.

Kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern Mediterranean region since the late Cretaceous

“…the Budva-Cukali zone [Robertson and Karamata, 1994]) to the Aegean domain in the southeast and possibly as far as the Lycian basin in the Taurides [Bonneau, 1984]. This basin had an original width of at least 300 km [van Hinsbergen et al, 2005b].…”

“…Located in the center of the Aegean domain, the Cyclades partly expose the buried parts of the Hellenides, exhumed since the Eocene as MCCs in low, medium and/or high temperature environments (figures 4 and 6) [Bonneau, 1984;Lister et al, 1984;Faure and Bonneau, 1988; M A N U S C R I P T…”

“…~15-20 kbar, ~500 °C) whose metamorphic peak is dated at ~50 Ma, forming the Cycladic Blueschists unit and the Cycladic basement [Bonneau and Kienast, 1982;Bonneau, 1984;Wijbrans and McDougall, 1988;Tomaschek et al, 2003;Lagos et al, 2007]. Exhumation of these metamorphic units first occurred between 45 and 35-30 Ma in a syn-orogenic context, following a cold retrograde path (figure 5) [Altherr et al, 1979;Bonneau and Kienast, 1982;Avigad and Garfunkel, 1989;Trotet et al, 2001].…”

“…The latter was partly accreted to the Pelagonian nappe contributing to the building of the Hellenides, while its buried part underwent early Eocene HP-LT metamorphism recorded in the Cycladic Blueschists unit and the Cycladic basement [Bonneau and Kienast, 1982;Bonneau, 1984;Wijbrans and McDougall, 1988;Tomaschek et al, 2003;Lagos et al, 2007]. These units were then progressively exhumed up to the end of the Eocene in the Cyclades and in the Olympos, Ossa and Pelion tectonic windows as a synorogenic extrusion wedge bounded by the Vari detachment on top (in Syros) and the SCSZ at the base (in Ios) (figure 9) Ring et al, , 2010Brun and Faccenna, 2008;Huet et al, 2009;Jolivet and Brun, 2010].…”

The tectono-metamorphic evolution of a dismembered ophiolite (Tinos, Cyclades, Greece)

“…1). Bonneau (1984) and Papanikolaou (1987) attribute the high pressure metamorphic event to the closure of the Mesozoic Pindos basin by subduction and eventual collision of the Apulian with the Pelagonian microplates. Dixon & Ridley (1987) have emphasized the accretionary wedge character of the high pressure metamorphic sequences of the northwest Cyclades.…”