| More


Views: 208 Downloads: 154
N. Lykakis, S. P. Kilias
N. Lykakis, S. P. Kilias


Manganese mineralization is hosted by a marine monomictic, lithic volcaniclastic breccia, possibly an andesitic in situ hyaloclastite, and shallow-marine or subaerial epiclastic conglomerates, in the Korakies area, NE Kimolos, active south Aegean volcanic arc. Old mine workings (in the form of rubble, adit and shaft), and abandoned rail and ship loading facilities, exist in the area. Mineralization occurs as a quartz/chalcedony vein system filling extensional NNE-SSW–trending faults and fractures, of Pliocene age. Maximum vein width reaches 5 m; length may extend to 250 m. The ore shares strong textural analogies with volcanic-hosted epithermal-style deposits, i.e. crustiform banding, vugs, hydrothermal breccias, cockade and comb textures. Vein wall rocks are hydrothermally altered to quartz-adularia±illite, chlorite and barite. Pyrolusite, hollandite, cryptomelane, and coronadite are the main ore minerals, with quartz, chalcedony, jasper and barite gangue. Ore samples contain up to 25.8 % MnO2, 14.7 % FeOTOT, 2860 ppm Zn, 1132 ppm Pb and 136 ppm Cu; Mn and Zn show mutual positive correlation (r2=0.61). Trace element enrichment (i.e. Zn, Pb, and Cu) may suggest a proximal base metal sulfide mineralization. Concentrations of 4.3 % Na, 0.09 % Mg and barite presence may suggest genetic involvement of sea water. The mineralization studied is similar to volcanic-hosted low-sulfidation epithermal ore deposits deposited from neutral pH fluids. This is a rare example of a vein-type epithermal-style hydrothermal manganese deposit formed in a marine environment.


epithermal manganese; Kimolos; South Aegean Volcanic Arc; hollandite; pyrolusite;

Full Text:



Alfieris, D., and Voudouris, P., 2007. High- and intermediate sulphidation Au-Ag-Te mineralization in a

shallow submarine setting, Milos island, Greece: Mineralogy and geological environment of formation.

In “Digging Deeper” C.J. Andrew et al (editors), v. 2, p. 893-896.

Canet, C., Prol-Ledesma, R.M., Proenza, J.A., Rubio-Ramos, M.A., Forrest, M.J., Torres-Vera, M.A.,

and Rodriguez-Diaz, A.A., 2005. Mn-Ba-Hg mineralization at shallow submarine hydrothermal vents

in Bahia Concepcion, Baja California Sur, Mexico, Chemical Geology, v. 224, I. 1-3, p. 96-112.

Christidis, G.E, 2001. Formation and growth of smectites in bentonites, a case study from Kimolos Island,

Aegean, Greece, Clays and Clay Minerals, v. 49, p. 204-215.

Cronan, D.S., 1986. Geochemical exploration for deep sea mineral deposits. In Thornton, I., Howarth, R.,

Graham and Trotman (eds), Applied Geochemistry in the 1980’s, London, p. 241–259.

Francalanci, L., Vougioukalakis, G.E., and Fytikas, M., 2007. Petrology and volcanology of Kimolos and

Polyegos volcanoes within the context of the South Aegean arc, Greece, GSA Special Papers, v. 418,

p. 33-65.

Fytikas, M., Innocenti, F., Kolios, N., Manetti, P., Mazuolli, R., Poli, G., Rita, F., and Villari, L., 1986.

Volcanology and petrology of volcanic products from the island of Milos and neighbouring islets,

J.volcanol.geotherm, Res. 28, p. 297-317.

Fytikas, M., and Vougioukalakis, G., 1993. Volcanic structure and evolution of Kimolos and Polyegos

(Milos Island Group), Bull.Geol.Soc.Greece, v. 28, p. 221-237.

Glasby, G.P., Papavassiliou, C.T., Mitsis, J., Valsami-Jones, E., Liakopoulos, A., and Renner, R.M., 2005.

The Vani manganese deposit, Milos Island, Greece: A fossil stratabound Mn-Ba-Pb-Zn-As-Sb-Wrich

hydrothermal deposit. In Fytikas, M. and Vougioukalakis, G.E. (eds), Developments in Volcanology,

Elsevier, Amsterdam, v. 7, p. 255-288.

Hauck, M., 1984. The barite deposits of Milos Island Greece. Unpubl. PhD Thesis, Univ. Karlsruhe, 241

pp (in German).

Hedenquist, J.W., Arribas, A., and Conzalez-Urien, E., 2000. Exploration for epithermal gold deposits,

Reviews in Economic Geology, v. 13, p. 245-278.

Hein, J.R., Stamatakis, M.G., and Dowling, J.S., 2000. Trace metal-rich Quaternary hydrothermal manganese

oxide and barite deposit, Milos Island, Greece, Applied Earth Science, section B, v. 109, p. 67-

Hein, J.R., Schulz, M.S., Dunham, R.E., Stern, R.J., and Bloomer, S.H., 2008. Diffuse flow hydrothermal

manganese mineralization along the active Mariana and southern Izu-Bonin arc system, western

Pacific, J. Geophys. Res., v. 113, B08S14.

Kilias, S.P., Naden, J., Cheliotis, I., Shepherd, T.J., Constandinidou, H., Crossing, J., and Simos, I., 2001.

Epithermal gold mineralization in the active Aegean volcanic arc: The Profitis Ilias deposit, Milos Island,

Greece, Mineralium Deposita, v.36, p. 32-44.

Kilias, S.P., Detsi, K., Godelitsas, A., Typas, M., Naden, J., and Marranitos, Y., 2007. Evidence of Mnoxide

biomineralization, Vani Mn deposit, Milos, Greece. In “Digging Deeper” C.J. Andrew et al

(editors), v. 2, p. 1069-1072.

XLIII, No 5 – 2655

Leal, P.R., Correa, M.J., Ametrano, S.J., Etcheverry, R.O., Milka, K., and de Brodtkorb, 2008. The manganese

deposits of the Pampean Ranges, Argentina, Canadian Mineralogist, v. 46, p. 1215-1233.

Liakopoulos, A., Glasby, G.P., Papavassiliou, C.T., and Boulegue, J., 2001. Nature and origin of the Vani

manganese deposit, Milos, Greece: an overview, Ore Geology Reviews, v. 18, p. 181–209.

Moore, W.S., and Vogt, P.R., 1976. Hydrothermal manganese crusts from two sites near the Galapagos

spreading axis: Earth Planet, Sci. Lett. v. 29, p. 349–356.

Naden, J., Kilias, S.P., Leng, M.J, and Cheliotis, I., 2003. Do fluid inclusions preserve δ18Ο values of

hydrothermal fluids in epithermal systems over geological time? Evidence from paleo- and modern

geothermal systems, Milos Island, Aegean Sea, Chemical geology, v. 197, p. 143-159.

Naden, J., Kilias, S.P., and Darbyshire, D.P.F., 2005. Active geothermal systems with entrained seawater

as analogues for transitional continental magmato-hydrothermal and volcanic-hosted massive sulfide

mineralization-the example of Milos Island, Greece, Geology, v. 33, p. 541-544.

Nicholson, K., 1992. Contrasting Mineralogical-Geochemical Signatures of Manganese Oxides: Guides

to Metallogenesis, Economic Geology, v. 87, p. 1253-1264.

Pe, G.G., and Piper, D.J.W., 1972. Volcanism at subduction zones; The Aegean area, Bull. Geol. Soc.

Greece, v. 9, p. 113-144.

Pe-Piper, G., and Piper, D.J.W., 2002. The Igneous rocks of Greece, Berlin, Gebruder Borntraeger, 573


Plimer, I., 2000. Milos Geologic history, KOAN Publishing House, Athens, 262 pp.

Post, J.E., 1999. Manganese oxide minerals: Crystal structures and economic and environmental significance,

Proc. Natl. Acad. Sci. USA, v. 96, p. 3447–3454.

Rogers, T.D.S., 1996. The geochemistry of ferromanganese crusts and sediments from the southern Pacific,

Ph.D. Thesis, University of London.

Rogers, T.D.S., Hodkinson, R.A., and Cronan D.S., 2001. Hydrothermal Manganese Deposits from the

Tonga-Kermadec Ridge and Lau Basin Region, Southwest Pacific, Marine Georesources and Geotechnology,

v. 19, p. 245-268.

Roy, S., 1968. Mineralogy of the different genetic types of manganese deposits, Econ. Geol., v. 63, p. 760–

Roy, S., 1997. Genetic Diversity of Manganese Deposition in the Terrestrial Geological Record. In Nicholson,

K., Hein, J.R., Biihn, B. and Dasgupta, S. (eds), Manganese Mineralization: Geochemistry and

Mineralogy of Terrestrial and Marine Deposits, Geological Society Special Publication, No. 119, p.


Skarpelis, N., and Koutles, T., 2004. Geology of epithermal mineralization of the NW part of Milos Island:

Greece, 5th International Symposium on Eastern Mediterranean Geology, Thessaloniki, Greece.

Stewart, A.L., and Mcphie, J., 2006. Facies architecture and Late Pliocene – Pleistocene evolution of a

felsic volcanic island, Milos, Greece, Bulletin Volcanology, v. 68, p.703-726.


  • There are currently no refbacks.

Copyright (c) 2017 N. Lykakis, S. P. Kilias

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.