Unit:
Κατεύθυνση Ορυκτολογία και ΠετρολογίαLibrary of the School of Science
Author:
Ξυπνητός Δημήτρης
Supervisors info:
Βουδούρης Παναγιώτης, Αναπληρωτής Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Kouzmanov Kalin, Doctor, Department of Earth Sciences, University of Geneva
Μαγγανάς Ανδρέας, Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Original Title:
Ore mineralogy of the Serifos Granodiorite, Cyclades, Greece: Genetic relationship with the skarn formation in the southwestern Serifos
Translated title:
Ore mineralogy of the Serifos Granodiorite, Cyclades, Greece: Genetic relationship with the skarn formation in the southwestern Serifos
Summary:
The Serifos district is part of the Attico-Cycladic-Pelagonian ore belt. The island is known for mining activity through the ancient times and in the last century (1880-1950), mainly exploiting an Fe-skarn deposits, as described by Salemink (1985) and Ducoux et al. (2017). Three tectono-metamorphic units have been distinguished in the island, from the bottom to the top the Continental Cycladic Basement (CCB): the Cycladic Blueschist Unit (CBU) and the Upper Cycladic Unit (UCU) along with an I-type granodiorite intrusion emplaced at 11,6 to 9,5 Ma penetrating the rocks of the CCB and the CBU units and causing contact metamorphism in the proximal marbles and schists, consequently forming calcic exo- and endo-skarns as long as carbonate-replacement ores and retrograde low-temperature veins. In the southeastern part of the island, another igneous body crops out, described recently by Voudouris (2010) as ‘’leucogranite’’ and called ‘’aplogranite’’ in this study. The present study has been focused on five mineralized areas within the granodiorite and the aplogranite bodies. The first prospect is located in the Chora area within the inner part of the granodiorite and consists of disseminated pyrite and chalcopyrite mineralization, along with goethite pseudomorphs after pyrite and magnetite as veins. Secondary malachite and azurite also occur in this area. The second prospect is a sheeted quartz vein system located in the Koutalas area, within the outer part of the granodiorite. The sheeted veins trend E-W and represent a possible pathway (e.g. feeder zones) for the magmatic aqueous fluids migrating laterally and upwards within the marbles of the CBU. The third prospect in the Sotiras area within the aplogranite, is characterized by a disseminated pyrite mineralization where pyrite occurs inside miarolitic cavities. Large quartz veins without ore minerals also occur in this area. The fourth prospect is located in the Kefala area and is characterized by pyrite dissemination within the aplogranite. Finally, the fifth prospect in the Heliport area in the inner part of the granodiorite, is a sulfide stockwork-type mineralization consisting mainly of quartz pyrite, chalcopyrite and Ti-oxides (anatase/rutile). In one sample, native bismuth and bismuth sulfosalt have been found. In the Koutalas prospect, an extended sodic alteration affects the granodiorite, while in the Heliport area a less intense sericitic alteration occurs. No such alterations have been found in the Sotiras area where the aplogranite is the dominant body. Moreover, we provide new microthermometric data from the quartz sheeted veins in the Koutalas area and from the quartz veins in the Sotiras area. The measured inclusions present a range of homogenization temperatures from 200° to 550°C with a mean temperature of 350°C, while the measured salinity ranges from 5 to 45 wt%NaCl equiv. The major goal of this study is to understand how the relationship between all these prospects and their possible genetic relation with the skarn mineralization in the southwestern part of Serifos
Main subject category:
Science
Keywords:
Ore mineralogy, Granodiorite, Aplogranite, Serifow, Skarn deposit, Sodic- alteration, Fluid inclusions
