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dc.contributor.author
Brett-Adams, Alannah C.
dc.contributor.author
Diamond, Larryn W.
dc.contributor.author
Petrini, Claudio
dc.contributor.author
Madonna, Claudio
dc.date.accessioned
2021-08-05T12:33:53Z
dc.date.available
2021-08-05T03:15:13Z
dc.date.available
2021-08-05T12:33:53Z
dc.date.issued
2021-09-20
dc.identifier.issn
0040-1951
dc.identifier.issn
1879-3266
dc.identifier.other
10.1016/j.tecto.2021.228994
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/499554
dc.identifier.doi
10.3929/ethz-b-000499554
dc.description.abstract
Hydrothermal circulation through oceanic crust, and all the transfers of mass and heat caused by this circulation, are controlled by the evolving permeability of the altered basaltic rocks at in-situ pressures (P) and temperatures (T). Numerical models designed to elucidate these processes therefore rely on knowledge of the rock-matrix permeabilities as a function of P and T and degree of hydrothermal alteration. We provide the first measurements of changes in permeability of two major types of high-temperature alteration of basalts, i.e., spilites and epidosites, over the P–T range relevant to hydrothermally active oceanic crust. Experiments were performed on microfracture-poor samples of pervasively altered pillow lavas and sheeted dikes from the Semail (Oman) and Troodos (Cyprus) ophiolites. Gas permeameter measurements at room temperature show that compression to ~55 MPa effective pressure reduces the permeabilities of spilites and epidosites by approximately ~80%. Measurements at 50 MPa effective pressure using an oscillating flow apparatus show that heating spilites and epidosites from 25 to 450 °C reduces their permeabilities by ~40% and 50%, respectively. SEM observations before and after the experiments rule out formation of new microfractures. The small reduction in permeability upon heating is attributed to closure of the sparse pre-existing microfractures (> 200 μm) due to thermoelastic expansion of the crystalline matrix combined with local restriction of throats between interstitial pores due to anisotropic mineral expansion. Temperature cycling demonstrates that these changes in permeability are reversible. Duplicate measurements on cores drilled from the same rock samples reveal that all these effects are small compared to the natural heterogeneity of permeability in spilites and epidosites at the centimeter scale. Nevertheless, our quantitative temperature–permeability correlations at subseafloor pressures allow the changes in permeability for these alteration types to be incorporated into numerical simulations of water–rock interaction in the oceanic crust.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Elsevier
en_US
dc.rights.uri
http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject
Permeability
en_US
dc.subject
High temperature experiments
en_US
dc.subject
Hydrothermally altered basalt
en_US
dc.subject
Spilite
en_US
dc.subject
Epidosite
en_US
dc.subject
Seafloor
en_US
dc.title
Influence of in-situ temperatures and pressures on the permeability of hydrothermally altered basalts in the oceanic crust
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
dc.date.published
2021-07-17
ethz.journal.title
Tectonophysics
ethz.journal.volume
815
en_US
ethz.journal.abbreviated
Tectonophysics
ethz.pages.start
228994
en_US
ethz.size
15 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Amsterdam
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09636 - Behr, Whitney / Behr, Whitney
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09636 - Behr, Whitney / Behr, Whitney
ethz.date.deposited
2021-08-05T03:15:17Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2021-08-05T12:33:59Z
ethz.rosetta.lastUpdated
2022-03-29T10:57:24Z
ethz.rosetta.versionExported
true
ethz.COinS
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