Unit:
Department of Geology and GeoenvirommentLibrary of the School of Science
Author:
Latsinoglou DImitrios
Supervisors info:
Παναγιώτης Βουδούρης, Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Μιχαήλ Σταματάκης, Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Original Title:
Precious metal potential in epithermal- vein-type barite-quartz mineralization in eastern Milos island, Cyclades, Greece.
Translated title:
Precious metal potential in epithermal- vein-type barite-quartz mineralization in eastern Milos island, Cyclades, Greece
Summary:
This thesis reports for the first time on the occurrence of mercurian gold and electrum (with up to 25.5 wt% Hg), and Ag and Au bearing tellurides petzite (AuAg3Te2) and hessite (Ag2Te) with Ag-bearing galena from intermediate-sulfidation (IS) Pb-Ag±Au-Te-Hg quartz-barite veins and breccias at eastern Milos Island. The mineralization is associated with silicic, and advanced argillic altered tuffs and lava flows, considered to be products of steam-heated alteration overprinting earlier formed boiling zones with sericite and adularia. A genetic model is suggested here, where the deeper sericite-adularia intermediate-sulfidation system seems to be overprinted by a steam-heated zone due to contemporaneous tectonic uplift and hydrothermal activity. Steam-heated alteration overprinted the preexisting epithermal mineralization, leaving precious metals in the preexisting IS veins enough to achieve ore grade. Tellurium and mercury were concentrated in magmatic gases (and/or boiled vapors), which then condensed in the meteoric- and/or seawater-dominated, epithermal, ore-forming liquid, where it reacted with the dissolved gold and silver species to deposit telluride minerals and mercurian electrum.
The acid-sulfate water responsible for the steam heated alteration results from groundwater absorption of H2S-bearing steam derived from boiling of the deeper, neutral-pH geothermal water. SEM images indicate that the tabular-like alunite/natroalunite includes pseudocubic crystals of P, Ba, Sr, REE and Ca bearing APS (aluminum-phosphate minerals), mainly svanbergite. There are formed at early stages before alunite crystallization from a high phosphorous/sulfur ratio solution.
The available data suggest the presence of a buried porphyry-style mineralization beneath the area and emphasizes similar mineralizing processes associated with boiling zones throughout the whole Milos island.
Notes: Unfortunately, due to the Covid-19 pandemic, further sample-collecting and more precise chemical analyses of the samples were unable to be achieved. As a result, we had to content ourselves with the data we had already collected.
Main subject category:
Science
Keywords:
epithermal mineralization, intermediate sulfidation, steam-heated zone, APS minerals, telluride mienrals
File:
File access is restricted until 2024-08-02.
Latsinoglou-BSc thesis.pdf
3 MB
File access is restricted until 2024-08-02.
