Mineral composition of mafic minerals and ore deposition from the Kassiteres (Sappes) and Pagoni Rachi ( Kirki) porphyry Cu-Mo prospects / W. Thrace


Published: Jan 1, 2001
Keywords:
porphyry copper - molybdenum magmatic and hydrothermal biotites amphiboles late magmatic - early hydrothermal fluids oxidation
Π. ΒΟΥΔΟΥΡΗΣ
Abstract

The porphyry Cu-Mo mineralizations at Kassiteres and Pagoni Rachi are genetically related with dioritic to dacitoandesitic subvolcanic rocks that were and preliminary microthermometric data indicate that the hypogene mineralizations were introduced during albitic / potassic alteration of the intrusives and temperatures about 400°C from boiling magmatic-hydrothermal fluids. Electron microprobe major element analyses are presented for magmatic and hydrothermal biotites and amphiboles from both occurences. Hydrothermal biotites in the albitic / potassic zones are more magnesian than their magmatic counterparts and therefore close to phlohopite end - member composition. The amphiboles from Kassiteres range from magnesio - hornblende to actinolite, commonly within the same grain. Moreover the chemical data in both magmatic and hydrothermal biotites and amphiboles from the above two occurences indicate a Mg - and Si - enrichment and a Ti - depletion during crustallization and cooling from magmatic to late magmatic - early hydrothermal conditions. It is likely that an increase in oxyzen fugacity accompanied their chemical evolution. This oxidation trend is associated with the fluid exsolution of the magmas resulting in the development of the studied porphyry type mineralizations. Elements, which are also depleted from Mg - rich (more oxidized) amphiboles and biotites (K, Na, Fe and Ti) are partitioned in the magmatic - hydrothermal fluid phase and are responsible for the albitic / potassic altaration of both occurences.

Article Details
  • Section
  • Geochemistry and Ore Deposit Geology
Downloads
Download data is not yet available.
References
ARIKAS, Κ., 1979, Ein porphyrisches Mo - Cu - Vorkommen bei Kirki (Thrakien, Nordgriechenland. Ν. Jb. Miner, Abh. 137(1): 74-82
ARIKAS, K., 1981, Subvulkanisch - hydrothermale Mo - Cu - Pb - Zn - Vererzungen, S.E. Rhodopen, Nordgriechenland: Pétrographie und Geochemie, Tschermaks Min. Petr. Mitt., 28: 189 - 205.
ARIKAS, K., & VOUDOURIS, P. (1998) Hydrothermal alterations and mineralizations of magmatic rocks in the southern Rhhodope Massiv. Acta Vulcanologica, 10 (2): 353 - 365
ΒΟΥΔΟΥΡΗΣ, Π & ΑΡΙΚΑΣ, Κ., 1998, Προχωρημένη αργιλλική εξαλλοίωση μαγματικών περιοχής Κασσίτερων (Θράκη): Ορυκτολογία και περιβάλλον απόθεσης Bull. Geol. Soc. Greece, XXXII / 3: 69 - 78.
BRIMHALL, G.H. & CRECAR, DA., 1987. Ore fluids: magmatic to supergene. In: Thermodynamic modeling of geological materials: minerals, fluids and melts. CARMICHEAL I.S.E. & EUGSTER, H.P. (eds.). Reviews in Mineralogy, Miner. Soc. Amer. 17: 235 - 321.
CHIVAS, A.R., 1981, Geochemical evidence for magmatic fluids in porphyry copper Contr. Miner. Petrol., 78: 389 - 403.
HOWTHORNE, EC, 1983, The crystal chemistry of the amphiboles. Can. Mineral, 21 (2): 173 - 180.
HENDRY, D.A.F., CHIVAS, A.R., REED, S.J.B., and LONG, J.V.P., 1981, Geochemical evidence for magmatic fluids in porphyry copper mineralization. Part II. Ion probe analysis of Cu contents of mafic minerals, Koloula igneous complex. Contr. Miner. Petrol., 78: 404 - 412.
HENDRY, D.A.F., CHIVAS, A.R., LONG, J.V.P., and REED, S.J.B., 1985, Chemical differences between minerals from mineralizing and barren instrusions from some North American porphyry copper deposits. Contr. Miner. Petrol., 89:317-329.
HENDRY, D.A.F., GUNOW, A.J., SMITH, R.P., REEK, S J.B., and LONG, J.V.P, 1988, Chemical differences between minerals from mineralizing and barren intrusions associated with molybdenum mineralization at Climax, Colorado. Miner. Petrol., 39: 251 - 263.
JACOBS, D.C. & PARRY, W.T., 1979, Geochemistry og biotite in the Santa Rita porphyry copper deposit, New Mexico. Econ. Geology, 74: 860
ΚΑΤΙΡΤΖΟΓΛΟΥ, K., 1986. Μεταλλογένεση των Τριτογενών θειούχων μεταλλοφοριών περιοχής Αισΰμης, νομός Έβρου. Αδημοσίευτη Διδακτ. Διατριβή, Παν/μιο Αθηνών, 176 σ.
LEAKE, Β.Ε., 1971, On aluminous and edenitic hornblendes. Mineral. Mag., 38: 389 - 407.
LEAKE, B.E., 1978, Nomenclature of amphiboles. Am. Mineralogist. 63: 1023 - 1052.
MASON, D.R., 1978, Compositional variations in ferromagnesian minerals form porphyry copper - generating and barren intrusions of the Western Highlands, Papua New Guinea. Econ. Geology, 73: 878 - 890.
MELFOS, V., 1995, Investigations of the base and precious metals of the Circum Rhodope Belt in Thrace. Unpub. Ph. D. thesis, Univ. Thessaloniki, 287 pp (in Greek).
MICHAEL , K., CONSTANTINIDES, D., ASHWORTH, K., PERDIKATSIS, V. & DEMITRIADIS, Α., 1989, The Kirki vein polymetallic mineralization, NE Greece. Geol. Rhodopica, 1: 322 - 329.
MOORE, W.J. & CZAMANSKE, G.K., 1973, Compositions of biotites from unaltered and altered monzonitic rocks in the Bingham mining district, Utah. Econ. Geology, 68: 269 - 274. ROEDDER, E., 1984, Fluid inclusions, in: Ribbe, PH. (ed.), Mineral. Soc America: Rev. in Mineralogy. 12, pp 644.
SOURIRAJAN, S. & KENNEDY, G.C., 1962, The system H20 - NaCl at elevated temperatures and pressures. Am. Jour. Sci., 260: 115-141.
SPENCER, K.J. & LINDSLEY, D.H., 1981, A solution model for coexisting iron - epithemal vein - type gold - silver mineralizations at Kassiteres / Sapes, (NE - Greece). Unpub. Ph.D. thesis., Univ. Hamburg, 218 pp (in German).
VOUDOURIS, P. (1997) Epithermal and porphyry type mineralizations in Kassiteres Exploration - where do they meet?, Balkema pubi. 683 - 686.
WONES, S.A. & EUGSTER, H.P, 1965, Stability of biotite: Experiment, theory and application. Amer. Mineral., 50: 1228 - 1272.
Most read articles by the same author(s)