Zersetzung von Kalk-Alkali-Gesteinen im rezenten Fumarolengebiet auf Nea Kameni/Santorin/Griechenland

Schorin, H.

doi:10.1007/bf01869035

Cited by 4 publications

(2 citation statements)

References 14 publications

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“…Chemical composition of fumaroles was investigated by many authors. In the Nea Kameni/Santorin area, Butuzova (1966), Georgalas (1940), Georgalas andPapastamatiou (1951, 1953), and Schorin (1980) found a high concentration of CO2 and SO2 in the hot vapors, and proposed that H2SO 4 was the major factor altering the rocks by modifying their chemical composition, in particular the A1203, Fe203, TiO z and K20 contents. In Alaska, Kodosky and Keith (1995) found halide spe- cies, e.g., chlorides and fluorides, in the vapor phase.…”

Section: Processes Influencing Biotite Evolution At Tazzekamentioning

confidence: 99%

Chemical Changes and Genesis of Secondary Minerals During the Alteration of Biotites from Ignimbrites in the Tazzeka Mountain (Morocco)

Dejou¹,

Kimpe

Macaire

et al. 1999

Clays and clay miner.

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Abstract--The Tazzeka Mountain, located approximately 20 km south of Taza, eastern Morocco, is composed of a Westphalian volcano-sedimentary complex. It contains rhyolitic ignimbrites with the following minerals: quartz, potassium feldspar, oligoclase-andesine, and biotite. The ignimbrites are extensively altered because of a dense network of fractures in the massif. Alteration has resulted in the formation of spheroidal rocks and saprolite, the thickness of which depends on local topography. The evolution of the biotites in the ignimbrites was investigated by microprobe analysis of the mica crystals. This technique provides data that are not accessible through classical analytical methods. Biotites are transformed into secondary clay minerals, mainly chlorites and illites; intermediate stages are related to the degree of alteration of biotite, the latter being expressed by the K20 content which decreases progressively from 7.3 to 1.3%. Next come protochlorites and chlorites sensu stricto, in which the K20 content is 0.3%. Several processes including retrodiagenesis, hydrothermal activity, fumarolic activity, and geochemical weathering contributed to the transformation of the biotites at Tazzeka.

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Section: Processes Influencing Biotite Evolution At Tazzekamentioning

confidence: 99%

Chemical Changes and Genesis of Secondary Minerals During the Alteration of Biotites from Ignimbrites in the Tazzeka Mountain (Morocco)

Dejou¹,

Kimpe

Macaire

et al. 1999

Clays and clay miner.

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show abstract

“…The volcanic activity manifests itself in sporadic lava eruptions and less spectacular but continuous fumarolic exhalations. The latter have locally altered the originally erupted calc-alkaline volcanics (Schorin, 1980), and are responsibe for the current production of submarine iron oxide deposits (Behrend, 1936;Puchelt et al, 1973).…”

Section: S a N T O R I N Imentioning

confidence: 99%

Iron oxide mineralogy of a hydrothermal assemblage on Santorini Island, Aegean Sea

Murad

1982

Mineral. mag.

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ABSTRACT. Basement rocks of Santorini have been locally impregnated by iron oxides and other minerals. The hydrothermal fluids which caused the mineralization have extensively altered the impregnated rocks, but left granditic garnets in these unaffected.M6ssbauer spectroscopy and differential X-ray diffraction show that the iron oxides present are goethite and hematite in a ratio of about 2: 1. The presence of hematite indicates that these minerals formed, directly from a hydrothermal phase, at higher temperatures than the recent submarine iron oxide deposits of Santorini, which contain no hematite.

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Alteration processes in volcanic soils and identification of exobiologically important weathering products on Mars using remote sensing

Bishop¹,

Fröschl²,

Mancinelli³

1998

J. Geophys. Res.

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Abstract. Determining the mineralogy of the Martian surface material provides information about the past and present environments on Mars which are an integral aspect of whether or not Mars was suitable for the origin of life. Mineral identification on Mars will most likely be achieved through visible-infrared remote sensing in combination with other analyses on landed missions. Therefore, understanding the visible and infrared spectral properties of terrestrial samples formed via processes similar to those thought to have occurred on Mars is essential to this effort and will facilitate site selection for future exobiology missions to Mars. Visible to infrared reflectance spectra are presented here for the fine-grained fractions of altered tephra/lava from the Haleakala summit basin on Maui, the Tarawera volcanic complex on the northern island of New Zealand, and the Greek Santorini island group. These samples exhibit a range of chemical and mineralogical compositions, where the primary minerals typically include plagioclase, pyroxene, hematite, and magnetite. The kind and abundance of weathering products varied substantially for these three sites due, in part, to the climate and weathering environment. The moist environments at Santorini and Tarawera are more consistent with postulated past environments on Mars, while the dry climate at the top of Haleakala is more consistent with the current Martian environment. Weathering of these tephra is evaluated by assessing changes in the leachable and immobile elements, and through detection of phyllosilicates and iron oxide/oxyhydroxide minerals. Identifying regions on Mars where phyllosilicates and many kinds of iron oxides/oxyhydroxides are present would imply the presence of water during alteration of the surface material. Tephra samples altered in the vicinity of cinder cones and steam vents contain higher abundances of phyllosilicates, iron oxides, and sulfates and may be interesting sites for exobiology.

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Zersetzung von Kalk-Alkali-Gesteinen im rezenten Fumarolengebiet auf Nea Kameni/Santorin/Griechenland

Cited by 4 publications

References 14 publications

Chemical Changes and Genesis of Secondary Minerals During the Alteration of Biotites from Ignimbrites in the Tazzeka Mountain (Morocco)

Chemical Changes and Genesis of Secondary Minerals During the Alteration of Biotites from Ignimbrites in the Tazzeka Mountain (Morocco)

Iron oxide mineralogy of a hydrothermal assemblage on Santorini Island, Aegean Sea

Alteration processes in volcanic soils and identification of exobiologically important weathering products on Mars using remote sensing

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