Abstract
Hydrothermal quartz veins associated with gold and silver mineralization and variable amounts of base metal sulfides have been discovered within an active geothermal system in the Megala Therma area of northern Lesbos. This geothermal system is probably a late evolutionary stage in the formation of this mineralization. The veins are hosted in Upper Miocene volcanic rocks of andesitic composition and consist of quartz, adularia, chlorite, sericite, illite, kaolinite, baryte, small amounts of jarosite and alunite, and native gold, pyrite, galena, sphalerite, chalcopyrite, bornite, chalcocite, covellite and goethite. The principal types of alteration which occur in the studied area are: silicification, propylitization, argillic alteration and potassic, phyllic alteration.
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Kontis, E., Kelepertsis, A.E. & Skounakis, S. Geochemistry and alteration facies associated with epithermal precious metal mineralization in an active geothermal system, northern Lesbos, Greece. Mineral. Deposita 29, 430–433 (1994). https://doi.org/10.1007/BF01886962
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DOI: https://doi.org/10.1007/BF01886962