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| Titel |
Reaction-induced porosity and onset of carbonation in abyssal peridotites: insights from 3D high-resolution microtomography |
| VerfasserIn |
Niels Jöns, Wolf-Achim Kahl, Wolfgang Bach |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076678
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| Zusammenfassung |
| Serpentinites are products of hydrous alteration of ultramafic rocks and they are particularly
common at slow-spreading mid-oceanic ridges, where tectonic faulting causes exposure of
abyssal peridotites at the seafloor. Upon interaction with seawater, the chemical composition
as well as the physical properties of peridotites change, and both hydration and carbonation
are common. To understand the underlying processes, we performed a detailed study on
harzburgite samples from ODP Leg 209 Site 1270D, located at the Mid-Atlantic ridge near
14°45’N.
The study focused on one sample taken just 0.75 metres below seafloor. Detailed thin
section microscopy revealed a high degree of serpentinization, but relict orthopyroxene
(Mg/[Mg+Fe] = 0.91–0.92) and spinel are present. Locally, minor amounts of secondary talc
and amphibole were found. Former olivine is completely replaced by serpentine
(Mg/[Mg+Fe] = 0.95–0.97) and magnetite in mesh textures. Mesh centers commonly consist
either of empty space ( |
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