D. Papoulis
P. Tsolis-Katagas
C. Katagas

Zunyite [Ali3SÌ5C>2o(OH,F)i8CI], an extremely rare mineral, was found as an accessory mineral in highly altered rhyolitic rocks at Kefalos, southwestern Kos, and in a completely kaolinized rhyolitic dyke at Asfendiou, northeastern Kos. It is associated with dickite, kaolinite, quartz and minor pyrophyllite. Kos Island contains both Tertiary and Quaternary volcanic rocks. Zunyite has been identified by XRD and studied by SEM, EDS, Raman spectroscopy and FTIR spectroscopy. The presence of zunyite, in the highly altered samples is significant for the determination of the conditions of the hydrothermal alteration that took place. Zunyite crystals, are up to 90 pm in diameter but usually are less than 10 pm; the crystals are partly covered by kaolinite layers. EDX analyses on the surface of zunyite revealed AI2O3/S1O2 values raging from 2.6 to 2.7. The occurrence of zunyite suggests incorporation of hydrothermal fluids rich in F" and CI", thus indicating contamination by seawater

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  • Mineralogy and Crystallography
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Baur W.H. & Ohta T. 1982. The SisOi6 pentamer in zunyite refined and empirical relations for individual siliconoxygen bonds. Acta Crystallogr., B38, 390-401.
Boven Α., Brousse R., Dalabakis P. & Pasteels P. 1987. Geological and geo-chronological evidences on the evolution of KOS-JALI-NISYROS eruptive centres, Aegean arc, Greece. Terra Cognita, 7, 328-329.
Dalabakis P. 1987. La volcanisme recent de I ' île de Kos. Thèse de doctorat, Paris. XI. 266p.
Dill H.G., Bosse R., Henning K-H. & Fricke A. 1997. Mineralogical and chemical variations in hypogene and supergene kaolin deposits in a mobil fold belt the Central Andes of northwestern Peru. Miner. Deposita, 32, 149-163.
Gadsden J.A. 1975. Infrared Spectra of Minerals and Related Inorganic Compounds. Butterworths, London, 180p.
Hsu L.C. 1985. Stability relations of zunyite under hydrothermal conditions. Geol. Soc. Am., Abstract Programs 17/98. Annual meeting of the Geological Society of America.
Inoue A. 1995. Formation of Clay Minerals in Hydrothermal Environments. In: Velde B., (ed), Origin and Mineralogy of Clays, Clays and the Environment, 268-329p.
Kloprogge JT. & Frost R.L. 1999. Raman and infrared microscopy study of zunyite, a natural Al13 silicate. Spectrochimica Acta Part A, 55, 1505-1513.
Louisnathan S.J. & Gibbs G.V. 1972. Aluminum-silicon distribution in zunyite. Amer. Mineral., 57, 1089-1108.
Papoulis D. 2003. Mineralogical study, kaolinitization processes and properties of kaolins from Leucogia, Drama and Kos Island. Ph. D Thesis, Univ. Patras, 289p.
Papoulis D. & Tsolis-Katagas P. 2001. Kaolinization process in the Rhyolitic rocks of Kefalos, Kos island, Aegean sea, Greece. Bull. Geol. Soc. Greece, 34/3, 867-874.
Pauling L. 1933. The crystal structure of zunyite, Ali3Si502o(OH,F)18CI. Z. Kristallogr., 84, 442-452.
Sillitoe R.H., Steele B.G., Thompson J.F.H. & Lang J.R. 1998. Advanced argillic lithocaps in the Bolivian tinsilver belt. Miner. Deposita, 33, 539-546.
Triantaphyllis M. 1994. Geological map of Greece, Western Kos (Kefalos) sheet, 1:50000,1.G.M.E., Athens.
Triantaphyllis M. 1998. Geological map of Greece, Eastern Kos sheet, 1:50000,1.G.M.E., Athens.
Turco G. 1962. La zunyite; recherches expérimentales physico-chimiques en liaison avec l'étude du nouveau gisement deBeni-Embarek. Bull. Soc. Française Mineralogie et Cristallographie, LXXXV, 407-458.
Willan R.C.R. & Armstrong D.C. 2001. Successive geothermal, volcanic-hydrothermal and contact metasomatic events in islands-arc basalts, South Shetland Islands. Durham meeting abstracts, 57-58.
Zagal'skaya Yu. G. & Belov N. 1964. Concerning the crystal structure of zunyite AI13(OH)18SÌ502oCI = [AI12(OH)i8 S1O4] [AI(S04)4]CI. Sov. Phys. Crystallogr., 8, 429-432.
Zhou Β. & Sherriff B.L. 2003. Nuclear Magnetic Resonance study of AI:Si and F:OH order in zunyite. Can. Mineralogist,
, 891-903.
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