Major- and trace-element mobility in altered volcanic rocks near Stypsi, Lesbos, Greece and genesis of a kaoline deposit

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doi: 10.1016/0169-1317(87)90011-1
Authors:Kelepertsis, A. E.; Esson, J.
Author Affiliations:Primary:
Univ. Athens, Dep. Geol., Athens, Greece
Univ. Manchester, United Kingdom
Volume Title:Applied Clay Science
Source:Applied Clay Science, 2(1), p.11-28. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0169-1317
Publication Date:1987
Note:In English. 34 refs.; illus. incl. 7 tables, geol. sketch maps
Summary:Major- and trace-element mobilities have been investigated in hydrothermally altered zones of Miocene volcanic rocks on the island of Lesbos. Three types of alteration have been recognized, and are characterized by the mineralogical composition: (a) zone of illite and smectite; (a-b) transitional zone of kaolinite, illite, smectite; and (b) zone of kaolinite. The following relationships between mineral paragenesis of the different alteration zones and element behaviour are apparent. 1) K and Rb enrichment relative to fresh volcanic rocks occurs in zones (a) and (a-b) while K and Rb are leached during destruction of illite in the kaolinite (b). 2) Zones (a) and (a-b) are characterized by depletion of Fe, Mg, Ca, Na, P, Sr, Zn, Cu, Ni and Ba when compared to the unaltered volcanic rocks. 3) Relative to the volcanic rock, the kaolinitic zone (b) is characterized by depletion of Fe, Mg, Ca, Na, K, P and Ti and enrichment of Al. Of the trace-elements, Nb, Zr, Ce, Nd and La are enriched whilst Sr, Rb, Zn, Cu, Ni, Cr, V, Ba and Sc are depleted. 4) There is no evidence of Cu, Ni, Cr, Zn or Mo addition to the system by the hydrothermal fluids. Recognition of the hydrothermal origin of Stypsi kaolin is based on the following criteria: 1) mineralogical zonation; 2) association of pyrite with hydrothermally altered zones; 3) Hg-geochemical anomalies of the alteration zones; and 4) comparison of the analytical data from the present study with relevant data on kaolins of known hydrothermal origin. [J.M.H.]
Subjects:Economic geology; Hydrothermal alteration; Kaolin deposits; Kaolinization; Major elements; Metasomatism; Mineral deposits, genesis; Paragenesis; Processes; Trace elements; Zoning; Aegean Islands; Europe; Greece; Greek Aegean Islands; Lesbos; Mediterranean region; Southern Europe; Hydrothermal processes; Stypsi
Abstract Numbers:87M/6048
Record ID:1987053874
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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