dc.contributor.author
Zertani, Sascha
dc.contributor.author
Vrijmoed, Johannes C.
dc.contributor.author
Tilmann, Frederik
dc.contributor.author
John, Timm
dc.contributor.author
Andersen, Torgeir B.
dc.contributor.author
Labrousse, Loic
dc.date.accessioned
2020-06-16T13:39:01Z
dc.date.available
2020-06-16T13:39:01Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/27656
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-27410
dc.description.abstract
Seismological studies of large‐scale processes at convergent plate boundaries typically probe lower crustal structures with wavelengths of several kilometers, whereas field‐based studies typically sample the resulting structures at a much smaller scale. To bridge this gap between scales, we derive effective petrophysical properties on the 20‐m, 100‐m, and kilometer scales based on numerical modeling with the finite element method. Geometries representative of eclogitization of crustal material are extracted from the partially eclogitized exposures on Holsnøy (Norway). We find that the P wave velocity is controlled by the properties of the lithologies rather than their geometric arrangement. P wave anisotropy, however, is dependent on the fabric orientation of the associated rocks, as fabric variations cause changes in the orientation of the initial anisotropy. As a result, different structural associations can result in effective anisotropies ranging from ~0–4% for eclogites not associated with ductile deformation to up to 8% for those formed during ductile deformation. For the kilometer‐scale structures, a scale that in principle can be resolved by seismological studies, we obtained P wave velocities between 7.7 and 8.0 km s−1. The effective P wave anisotropy on the kilometer scale is ~3–4% and thus may explain the backazimuthal dependence of seismological images of, for example, the Indian lower crust currently underthrusting beneath the Himalaya. These results imply that seismic anisotropy could be the key to visualize structures in active subduction and collision zones that are currently invisible to geophysical methods and thus can be used to unravel the underlying processes active at depth.
en
dc.format.extent
18 Seiten
dc.rights.uri
https://creativecommons.org/licenses/by/4.0/
dc.subject
descending crust
en
dc.subject
P wave anisotropy
en
dc.subject
eclogitization
en
dc.subject.ddc
500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::551 Geologie, Hydrologie, Meteorologie
dc.title
P wave anisotropy caused by partial eclogitization of descending crust demonstrated by modeling effective petrophysical Properties
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.articlenumber
e2019GC008906
dcterms.bibliographicCitation.doi
10.1029/2019GC008906
dcterms.bibliographicCitation.journaltitle
Geochemistry, geophysics, geosystems
dcterms.bibliographicCitation.number
6
dcterms.bibliographicCitation.volume
21
dcterms.bibliographicCitation.url
https://doi.org/10.1029/2019GC008906
refubium.affiliation
Geowissenschaften
refubium.affiliation.other
Institut für Geologische Wissenschaften / Fachrichtung Geochemie, Hydrogeologie, Mineralogie
refubium.funding
DEAL Wiley
refubium.note.author
Die Publikation wurde von der Freien Universität Berlin finanziert.
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access
dcterms.isPartOf.eissn
1525-2027