EPITHERMAL SYSTEMS AND GOLD MINERALIZATION IN WESTERN THRACE (NORTHERN GREECE)


C. Michael
Résumé

Extensive epithermal systems occur within the Tertiary volcanosedimentary basins of western Thrace northern Greece. Gold deposits or perspective gold districts, related to the above epithermal systems have been recently found in the area. The gold mineralization is of the high – sulfidation type and is associated to a diversity in composition and style volcanic activity. Sappes epithermal system is the most important (Saint Demetrios and Viper deposits) and has developed in volcanic "ocks of intermediate composition accompanied by subvolcanic intrusives (dacite - andésites) and plutonio rocks (quartz - monzodiorites). Saint Demetrios and Viper gold deposits are flat lying and of high sulfidation type mineralizations hosted in hydrothermal breccia zones. Petrota epithermal system has developed in volcanoclastic and epiclastic rocks (Perama Hill gold deposit), in rhyolites (location Othontoto) and within hyaloclastites and crystal tuffs (location Mavrokoryfi). The mineralized epithermal zones have strong structural control. Perama gold deposit occurs at the intersection of NS and NW trending epithermal zones. These structures represent the higher grade "feeder" system. Pefka epithermal system is hosted in more acid volcanic vocks (dacites, rhyodacites) and at its southern part (Pasa lofos area) the system is associated with a more alkaline suit (shoshonitic rocks). The mineralized silicifid zones at Pefka mine would correspond to concentric fractures (sheeted fracturing) parallel to the margin of the breccia pipe. The gold mineralization occurs in veins. In general gold occurs in the form of native gold, gold tellurides or it is associated with enargite, luzonite, tetrahedhte. Advanced argillic alteration and intense silicification are very important for the epithermal systems in western Thrace. A unique low - sulfidation occurrence was found at the central and southern part of Sappes area. Adularla was found in veinlets overlapping argillic alteration zones of high - sulfidation system.

Article Details
  • Rubrique
  • Economic Geology
Téléchargements
Les données relatives au téléchargement ne sont pas encore disponibles.
Références
Border, A. J. M., Michael, C, Constantinides, D. 1999. Discovery and evaluation of the Sappes gold deposits North - Eastern Greece. Conference Proceedings of new Generation GOLD 99. Perth, Western Australia, 22-23 November 1999.
Bridges, P. S., Gordon, M. J., Michael, C, Ambatzioglou, M. 1997. Gold Mineralisation at Sappes, Northern Greece. In Europe' s major gold deposits, Irish Association for Economic Geology, Abstracts volume, 95 - 107.
Cheliotis, J. Kilias, S., Shepherd, T., Naden., J., Michael, C, Bitzios, D., 1999. Models of epithermal systems in Rhodope area and Islands of Aegean. Internal report of IG.ME.
Corbett, G. J., Leach, T. M. 1977. Southwest Pacific rim Gold - Copper systems : Structure, Alteration and Mineralisation. Short course manual.
Dimou, E., Michael, C, Serment, R., 1994. Mineralogical composition of the epithermal polymetallic mineralisation of Pefka, Rhodope area. 7th Congress Geological Society of Greece, Abstracts.
Eliopoulos, D., Michael, C, Arvanitides, N., Constantinides, D., Katirzoglou, K., Kosmas, C, Demitroula, M. 1989. Primary gold mineralisation in the Greek Rhodope massif. Symposium "Gold 1989 in Europe" in Toulouse, France.
Lescuyer, J. L. , Bailly, D., Cassard, A. L. W. Lips & Piantone, P. Mc. Allster, M. 2003. Sediment - hosted gold in south - eastern Europe : the epithermal deposit of Perama, Thrace, Greece. Mineral Exploration and Sustainable Development et. al. (eds).
Me Alister M., Hammond, ο. M., Normand, D. & Kampasakalis, M. 1999. Discovery case history for the Perama Hill gold deposit, Greece. In : New Generation Gold Mines Conference in Perth, West Aust., 22 - 23 rd Nov 1999: 10 p.
Michael, C, Papadopoulos, P., Marantos, I., Evangelou, E., 1988. Epithermal gold mineralisation in Konos area. I.G.M.E., internal report.
Michael, C, Katirtzoglou, K., Perdikatsis, V., Constantinides, D. 1989. The polymetallic mineralisation of the Pefka area, Evros county, Greece. Geologica Rhodopica, 1 : 323 - 39.
Michael, C, Perdikatsis, V., Marantos, I. 1989. Mineralogy of the epithermal gold mineralisation in the Konos area, East Rhodope, Greece. Abstract to the 2nd Hellenic - Bulgarian symposium on the geological and physicogeographical problems of the Rhodope massif.
Michael, C, 1993. Geologa and Geochemistry of epithermal gold deposit in Konos area I.G.M.E., internal report.
Michael, C, Perdikatsis, V., Dimou, E., Marantos, I. 1995. Hydrothermal alteration and ore deposition in epithermal precious metal deposit of Agios Demetrios, Konos area, Northern Greece. Geol. Soc. Greece, sp. Pubi.., 4/2, : 778-782.
Michael C. 1999 Conceptual model of Konos epithermal system. Plate tectonic aspects of Alpine Metallogeny in the Carpatho - Balcan region 3rd annual meeting Athens, Sept. 1995,1.G.C.P. project 356.
Michael, C. 2002. Exploration - Valuation study of primary gold. I.G.M.E., internal report.
Simmons, S. F. 1995. Magmatic contributions to low sulfidation epithermal deposits, in Thompson, J.F.H. ed., Magmas, fluids and ore deposits. Mineralogical Association of Canada, short course handbook, v. 23 : 455-478.
Voudouris, P., Michael, C, Arikas, K. 1990. Ein porphyry - Cu - vorkommen und peripher epithermale alterationen in Kassiteres / Sape (Thrazien, Nordg - Riechenland : Ber. Deutsch. Miner. 1., 271.
Yanev, Y., Innocenti, F., Manetti, P. Serri G. 1998. Upper Eocene - Oligocene collision - related volcanism in Eastern Rhodopes (Bulgaria ) - Western Thrace (Greece) : Petrogenetic Affinity and Geodynamic Significance. Acta Vulganologica - vol 10 (2) - 1998 : 279 - 291.