Unit:
ΠΜΣ με ειδίκευση στην Εφαρμοσμένη Περιβαλλοντική ΓεωλογίαLibrary of the School of Science
Author:
Κοτοπούλου Ηλέκτρα
Supervisors info:
Στυλιανός Λόζιος Επίκ. Καθηγητής (Επιβλέπων) Αθανάσιος Γκοντελίτσας Επίκ. Καθηγητής, Παρασκευή Νομικού Λέκτορας
Original Title:
Geodynamical conditions in the shallow-sea hydrothermal system off SE Milos Island, Greece
Translated title:
Γεωδυναμικές συνθήκες στο ρηχό υποθαλάσσιο υδροθερμικό σύστημα στα ανοιχτά της ΝΑ Μήλου, Ελλάδα
Summary:
Shallow-sea hydrothermal vents of the volcanic island of Milos (Greece),
discharge hot (up to 111°C), H2S-rich and slightly acidic (pH 4-5) hydrothermal
fluids to the marine environment. The system hosts chemolithotrophic sulfide
oxidizing and sulfate reducing microbial communities that form white microbial
patches and facilitate precipitation of various S-bearing mineral phases,
including elemental S and Fe-sulfides.
This research aims to shed light on S-mineralogy and speciation in Milos
hydrothermal sediments. Following in-situ measurements of the local
physico-chemical parameters, surface cores (22 cm) were collected and sectioned
into 2 cm intervals. Preliminary investigation included bulk XRD
characterization and bulk ICP-MS analyses, along with SEM-EDS examination.
Abundant Fe-S phases mainly occur in 18-20 cm depth, where distinct metalloid
and chalcophile elements are also concentrated (As, Tl). Also, the radionuclide
content was studied using -ray spectrometry.
Synchrotron-based μ-XRF elemental maps, μ-XRD and S K-edge μ-XANES
spectroscopy, were utilized to examine S distribution and speciation in the
samples. S is mainly correlated to Fe and As, corresponding to both crystalline
and amorphous mineral phases. Except sulfidic sulfur, other oxidation states
have been detected in the solids, corresponding to sulfates and a variety of
mixed S-phases which are currently investigated by means of transmission
electron microscopy (TEM).
Keywords:
Sulfur, Milos, Hydrothermal system, Speciation, TEM
Number of index pages:
10
Number of references:
127
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