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| Titel |
Carbon storage potential in Pleistocene volcanic rocks of the Magnesia area (Central Greece) |
| VerfasserIn |
Petros Koutsovitis, Nikolaos Koukouzas, Andreas Magganas |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250140542
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| Publikation (Nr.) |
 EGU/EGU2017-3942.pdf |
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| Zusammenfassung |
| The Porfyrio and Mikrothives volcanoes in the Magnesia area (SE Thessaly, Central Greece)
are located a few km (∼8 and 12 km respectively) south-southwest of the industrial area of
Volos city and are relatively small in size (∼3 and 10 km2 respectively). They are closely
associated with other scattered volcanic centers of Late-Pleistocene-Quaternary age,
appearing at the western shores of Pagasitikos gulf and at the Northern Euboikos gulf
(e.g. Achilleion, Lichades, Agios Ioannis). This volcanic activity is attributed to
back-arc extensional volcanism and may be further associated with propagation
tectonics of the North Anatolian fault [1,2,3]. Volcanic rocks from the Porfyrio and
Mikrothives mostly consist of basaltic and trachyandesitic lavas and pyroclastic
tuffs.
Porous basaltic lavas (10-15% porosity) exhibit porphyritic textures with a holocrystalline
trachytic groundmass. The groundmass consists of lath-shaped plagioclase crystals,
alkali feldspar, clinopyroxene, olivine, oxide minerals (ilmenite, titanomagnetite and
magnetite), along with other accessory minerals such as quartz, calcite, apatite and pyrite.
Phenocrysts are mostly subhedral and anhedral clinopyroxene crystals (mostly augite
and less often diopside), olivine and less often plagioclase and quartz. Cr-spinel
crystals have been identified within olivine phenocrysts. Pyroclastic tuffs exhibit
vesicular textures, with their porosity varying between 20 and 40%. Their groundmass
is hypocrystalline vesicular being either trachytic or aphanitic, often enriched in
oxide minerals. Phenocrysts are less frequent compared to the lava samples, most
often being feldspars. In some samples, pores are partially filled with secondary
calcite.
From recent literature it is well known that CO2 can be injected, trapped and retained
within the pore spaces of volcanic rocks, forming chemically stable carbonate minerals
[4,5,6,7]. The Porfyrio and Mikrothives volcanics can be considered as potential sites for
applying in situ and under certain preconditions ex situ [8] geologic carbon capture and
storage (CCS) practices. This is due to the textural properties of the volcanic and pyroclastic
rocks that are characterized by their high porosity, the chemistry of the rocks, as they contain
rather high amounts of Ca, Mg, Fe – the necessary chemical constituents for forming stable
carbonate minerals, but also because of the relatively short distance of the outcrop of the
rocks with the industrial area of Volos city. It should be noted some of the studied
samples already incorporate calcite within the pores, demonstrating the capability of
these rocks for CCS applications. An estimated amount of about 3 tons of CO2,
dissolved in water, could be stored in the frames of a small pilot project either in the
Porfyrio or the Mikrothives volcanics, considering that the average porosity of these
volcanics is about 20%. CO2 storage could be possibly applied at a depth greater than
400 meters below the surface, occupying a minimum area of about 104 m3 [cf.
7].
References. [1] Fytikas et al. 1984: Geol Soc London Sp Publ 17, 687–699; [2] Pe-Piper
and Piper 2007: Geol Soc Am Sp Pap 418, 17–31; [3] Innocenti et al. 2010: Journal Geol
Soc London 167, 475–489; [4] Rochelle, et al. 2004: Geol Soc London Sp Publ
233, 87-106; [5] Rosenbauer et al. 2012: Geoch et Cosmoch Acta 89, 116-133; [6]
Matter, et al., 2007: Geochem. Geophys. Geosyst. 8; [7] Matter, et al., 2016: Science
352, 1312-1314.; [8] Rigopoulos et al. 2016: Journal CO2 Utilization 16, 361-370. |
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