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

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Publiée : янв. 1, 2001
DOI : https://doi.org/10.12681/bgsg.17126
E. MPOSKOS
Technical University of Athens, Section of Geological Sciences
D. K. KOSTOPOULOS
Aristotle University, School of Geology, Department of Mineralogy, Petrology and Economic Geology
A. KROHE
University of Muenster, Institute for Mineralogy, Laboratory for Geochronology
Résumé

A low-P / high-T metamorphic event (andalusite-sillimanite series) of pre-Alpine age, identified here for the first time, has affected the metapelitic rocks of the Vernon Massif. P-T conditions of metamorphism in the western part of the Massif are estimated at -2.5 kb / 600-610°C, while in the northeastern part they are estimated to have exceeded 4.5 kb / 640°C respectively. Such P-T conditions correspond to geothermal gradients of 68°C/ km and 40°C/km for the western and the northeastern parts of the Massif respectively. The inferred steep geothermal gradients require transport of heat from deeper to shallower levels within the crust, achieved via magmatic intrusions in a continental magmatic arc setting. Alpine overprinting is characterized by P-T metamorphic conditions of ~6 kb / <350°C in the western part and ~9 kb / <570°C in the northeastern part of the Massif respectively. Low-P / high-T metamorphic rocks, occurring as klippen in the Cyclades and as blocks in the ophiolitic milanges of Crete, are interpreted as remnants of the pre-Alpine Pelagonian nappe similar to those occurring in the Vernon Massif.

Article Details
  • Rubrique
  • Petrology
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Références
ALTHERR, R., KREUZER, H., LENZ, H., HARRE, W., AND DÜRR, S. 1994. Further evidence for a Late Cretaceous low-pressure/high temperature terrane in the Cyclades, Greece. Petrology and geochronology of crystalline rocks from the islands of Donoussa and Ikaria. Chem. Erde, 54, 310-328.
BERMAN, R.G. 1991. Thermobarometry using multiequilibrium calculations: a new technique with petrologie applications. Canadian Mineralogist, 29, 833-855.
BUCHER, Κ. Ν., AND FREY, M. 1994. Petrogenesis of metamoprhic 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).
KORONEOS, A. 1991. Mineralogy, petrology and geochemistry of the eastern Varnous pluton (NW Macedonia). Unpubl. PhD thesis, Univ. Thessaloniki, 271 pp.
LANGOSCH, Α., SEIDEL, E., STOSCH, H. G., AND OKRUSCH, M. 2000. Intrusive rocks in the ophiolitic mélange of Crete - Witnesses to a Late Cretaceous thermal event of enigmatic geological position. Contrib. Mineral. Petrol., 139, 330-355.
LIPS, A. L. W., WIJBRANS, J. R., AND WHITE, S. H. 1999. New insights from 40Ar/39Ar laserprobe dating of white mica fabrics from the Pelion Massif, Pelagonian zone, internal Hellenides, Greece: Implications for the timing of metamorphic episodes and tectonic events in the Aegean region. In: Durand, Β., Jolivet, L., Horvath, F, and Seranne, M.. (eds). The Mediterranean basins: Tertiary extension within the Alpine Orogen. Geol. Soc. London, Sp. Pubi., 156, 457-474.
MASSONNE, H. -J., AND SCHREYER, W. 1987. Phengite geobarometry based on the limiting assemblage with K-feldspar, phlogopite, and quartz. Contrib. Mineral. Petrol., 96, 212-224.
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).
MPOSKOS, E., AND PERRAKI, M. 2001. Alpine metamorphism of the pelagonian allochthon in the Kastania area (southern Vermion), (this volume).
SPEAR, F. S. 1995. Metamorphic phase equilibria and Pressure-Temperature-Time Paths. Min. Soc. Am., pp 799.
SEIDEL, E., OKRUSCH, M., KREUZER, H., RASCHKA, H., AND HARRE, W. 1981. Eo-Alpine metamorphism in the uppermost unit of the Cretan nappe system - petrology and geochronology. Part 2. Synopsis of high-temperature metamorphics and associated ophiolites. Contrib. Mineral. Petrol., 76, 351-361.
YARWOOD, G. Α., AND DIXON, J. E. 1977. Lower Cretaceous and younger thrusting in the Pelagonian rocks of the High Pieria, Greece. 6th Colloq. Aegean Region, Athens, v.l, 269-280.
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