dc.identifier.uri |
http://dx.doi.org/10.15488/3985 |
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dc.identifier.uri |
https://www.repo.uni-hannover.de/handle/123456789/4019 |
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dc.contributor.advisor |
Koepke, Jürgen |
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dc.contributor.author |
Currin Sala, Adriana M.
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dc.date.accessioned |
2018-11-19T07:22:24Z |
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dc.date.available |
2018-11-19T07:22:24Z |
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dc.date.issued |
2018-11-15 |
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dc.identifier.citation |
Currin Sala, Adriana M.: Cl-rich amphiboles as record for hydrothermal processes at very high temperatures in the deep oceanic crust : brine/rock interaction experiments and investigation on natural rocks. Hannover : Gottfried Wilhelm Leibniz Universität, Diss., 2018, 93 S. DOI: https://doi.org/10.15488/3985 |
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dc.description.abstract |
Interactions between rock and high temperature seawater-derived fluids are recorded in hydrothermal veins and dykelets that cross-cut layered olivine gabbros deep in the plutonic section of the Samail Ophiolite, Wadi Wariyah, Sultanate of Oman. Here we present a study – using petrographic, microanalytical, isotopic, and structural methods – of amphiboles found in the aforementioned veins and dykelets, which show a conspicuous compositional variation from high-Ti magnesiohastingsite and pargasite via magnesiohornblende and edenite, to Cl-rich ferropargasite and hastingsite (with up to 5.4 wt% Cl) and actinolite. These minerals record a wide range of formation conditions from magmatic to hydrothermal at varying water/rock ratios and salinities, while the formation of super Cl-rich amphibole suggests the occurrence of phase separation, and 87Sr/86Sr and stable δ18O isotope analyses confirm the influence of a hydrothermal fluid in a rock-dominated environment. A parallel experimental study was conducted at hydrothermal (500 – 750 °C) and magmatic (900 °C) conditions at pressures of 2 kbar, and fO2 close to NNO, with an amphibole-containing natural olivine gabbro and saline fluid (6, 20 and 50 wt% NaCl). Results in subsolidus experiments demonstrate the growth of newly-formed amphibole with a wide range of compositions comparable to those seen in the lithologies sampled in Wadi Wariyah, and Cl-bearing amphiboles with Cl up to 0.47 wt. %. Our findings highlight the heterogeneities in fluid infiltration and Cl activity that account for the complexity of hydrothermal fluid/rock interactions in deep oceanic geological systems, providing insight into the subsolidus evolution of gabbro-hosted amphibole-rich veins in the presence of a seawater-derived fluid. |
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dc.language.iso |
eng |
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dc.publisher |
Hannover : Institutionelles Repositorium der Leibniz Universität Hannover |
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dc.rights |
Es gilt deutsches Urheberrecht. Das Dokument darf zum eigenen Gebrauch kostenfrei genutzt, aber nicht im Internet bereitgestellt oder an Außenstehende weitergegeben werden. |
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dc.subject |
Cl-bearing amphibole |
eng |
dc.subject |
high-temperature hydrothermal activity |
eng |
dc.subject |
lower oceanic crust |
eng |
dc.subject |
Samail Ophiolite |
eng |
dc.subject |
phase separation |
eng |
dc.subject |
fluid-rock interaction |
eng |
dc.subject |
magmatic-hydrothermal transition |
eng |
dc.subject |
experimental petrology |
eng |
dc.subject |
Cl-haltige Amphibole |
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dc.subject |
Hochtemperatur Hydrothermale Aktivität |
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dc.subject |
Untere Ozeanische Kruste |
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dc.subject |
Samail Ophiolit |
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dc.subject |
Phasentrennung |
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dc.subject |
Fluid-Gesteins-Wechselwirkungen |
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dc.subject |
Magmatischer- hydrothermaler Übergangsbereich |
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dc.subject |
Experimentelle Petrologie |
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dc.subject.ddc |
550 | Geowissenschaften
|
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dc.title |
Cl-rich amphiboles as record for hydrothermal processes at very high temperatures in the deep oceanic crust : brine/rock interaction experiments and investigation on natural rocks |
eng |
dc.type |
DoctoralThesis |
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dc.type |
Text |
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dcterms.extent |
93 S. |
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dc.description.version |
publishedVersion |
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tib.accessRights |
frei zug�nglich |
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