NEW EVIDENCES OF THE LOW-P/HIGH-T PRE-ALPINE METAMORPHISM AND MEDIUM-P ALPINE OVERPRINT OF THE PELAGONIAN ZONE DOCUMENTED IN METAPELITES AND ORTHOGNEISSES FROM THE VORAS MASSIF, MACEDONIA, NORTHERN GREECE


E. Mposkos
A. Krone
Abstract

Pelitic rocks of the pre-Alpine "gneiss series" from the Voras Massif record a polymetamorphic history of three metamorphic events; a first HT event indicated by migmatitization phenomena, a subsequent LP-HT event (andalusite-sillimanite series) at 2.5-3 Kbar and 610-640°C, and a third medium-P event at ~11 Kbar and ~550°C. The LP-HT metamorphism is associated with intrusion of Variscan granitoid plutois in a magmatic arc setting. The medium-P metamorphism records an Alpine event (probably Early Cretaceous) indicated by kyanite, chlohtoid, garnet and staurolite formation replacing andalusite and cordierite. The Variscan granitoids and the overlying lithologies of the "schist series" are affected only by the medium-P metamorphism. Granitoids are transformed into phengite orthogneisses having the mineral assemblage phen (Si=3.35-3.47 a.p.f.u.)±Bt-Ab-Kfs- Qtz±Czo±Grt and high-alumina pelites into gamet-chloritoid schists with the mineral assemblage Grt-Ctd-Chl-Ms-Qtz-Rt±llm. The "schist series" which underlies the Late Triassic-Early Jurassic marbles and overlies lithologies of the "gneiss series" and metagranitoids represents protoliths of the Permo-Triassic volcanosedimentary series deposited at the eastern margin of the Pelagonian continental block

Article Details
  • Section
  • Petrology
Downloads
Download data is not yet available.
References
Avgerinas, Α., Kilias, Α., Koroneos, Α., Mountrakis, D., Frisch, W. and Dunkl, I., 2001: Cretaceous structural evolution of the Pelagonian crystalline in western Voras Mt. (Macedonia, Northern Greece). Bull.Geol.Soc. Greece. XXXIV/1, 129-136.
Barton, CM., 1976: The tectonic vector and emplacement age of an allochthonous basement slice in the Olympos area, N.E. Greece. Bull.Soc.Geol. France, 18, 253-258.
Berman, R.G., 1991: Thermobarometry using multiequilibrium calculations: a new technique with petrologie applications. Canadian Mineralogist, 29, 833-855.
Bucher, K.N., and Frey, M., 1994: Petrogenesis of metamorphic rocks. Springer Verlag, Berlin. 318 pp.
Katerinopoulos, Α., Kyriakopoulos, K., Del Moro, Α., Mitropoulos, P., and Giannoti, U., 1992: Comparative study of Hercynian granitoids from NW Greece and S. Yugoslavia. Chem. Erde, 52, 261-276.
Kilias, Α., and Mountrakis, D., 1989: The Pelagonian nappe. Tectonics, metamorphism and magmatism. Bull.Geol.Soc. Greece, 23/1, 29-46 (in Greek with English abstract).
Massonne, H. - J., and Schreyer, W., 1987: Phengite geobarometry based on the limiting assemblage with Kfeldspar, phlogopite, and quartz. Contrib. Mineral. Petrol., 96, 212-224.
Mountrakis, D., Sapountzis, E., Kilias, Α., Elefteriadis, G. and Christofidis, G., 1983: Paleogeographic conditions in the western Pelagonian margin in Greece during the initial rifting of the continental area. Can. J. Earth Sci., 20, 1673-1681.
Mountrakis, D., 1983: The geological structure of the northern pelagonian zone and the geotectonic evolution of the internal Hellenides. Habilit. Thesis. Univ. Thessaloniki, 289 p. (in Greek with English summary).
Most, T., Frisch, W., Dunkl, I., Kadosa, B., Boev, B., Avgerinas, A. and Kilias, Α., 2001: Geochronological and structural investigations of the northern Pelagonian crystalline zone. Constraints from K-Ar and zircon and apatite fission track dating. Bull.Geol.Soc. Greece. VXXXIV/1, 91-95.
Mposkos, E., and Perraki, M., 2001 : High pressure Alpine metamorphism of the pelagonian allochton in the Kastania area (southern Vermion), Greece. Bull. Geol. Soc. Greece V XXXIV/3, 939-947.
Mposkos, E., Kostopoulos, D. and Krohe, Α., 2001: Low-P/High-T pre-Alpine metamorphism and medium-P Alpine overprint of the Pelagonian zone documented in high-alumina metapelites from the Vernon Massif, Western Macedonia, Northern Greece. Bul.Geol.Soc. Greece V. XXXIV/3, 949-958.
Mposkos, E., Krohe, A. and Perraki, M., 2003: Record of Variscan Low-P/High-T metamorphism in Alpine medium-P rocks of the Pelagonian zone. Greece. EGS-AGU-EUG Joint Assembly. Nice, France. Abstract.
Reischmann, T., Kostopoulos, D., Loos, S., Anders, B., Avgerinas, A. and Sklavounos, S., 2001: Late Palaeozoic magmatism in the basement rocks southwest of Mt. Olympos, central Pelagonian zone, Greece: Remnants of a Permo-Carboniferous magmatic arc. Bull.Geol.Soc. Greece. XXXIV/3, 985-993.
Yarwood, G.A. & Aftalion, M., 1976: Field relations and U-Pb geochronology of a granite from the Pelagonian Zone of the Hellenides (High Pieria, Greece). Bull Soc. Geol. DE France ., 18, 259-264.
Yarwood, G.A. & Dixon, J.E., 1977: Lower Cretaceous and younger thrusting in the Pelagonian rocks of High Pieria, Greece. Colloq. Aegean Region, Athens, 6th, 1, 269-280.
Most read articles by the same author(s)