Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica)
Volcanic rocks forming sills, dykes or lava flows may display a magnetic anisotropy derived from the viscous flow during their emplacement. We model a sill as a steady-state flow of a Bingham fluid, driven by a pressure gradient in a horizontal conduit. The magma velocity as a function of depth is c...
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fthighwire:oai:open-archive.highwire.org:gji:128/1/230 2023-05-15T13:56:55+02:00 Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) Dragoni, Michele Lanza, Roberto Tallarico, Andrea 1997-01-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/128/1/230 https://doi.org/10.1111/j.1365-246X.1997.tb04083.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/128/1/230 http://dx.doi.org/10.1111/j.1365-246X.1997.tb04083.x Copyright (C) 1997, Oxford University Press Articles TEXT 1997 fthighwire https://doi.org/10.1111/j.1365-246X.1997.tb04083.x 2012-11-23T22:13:41Z Volcanic rocks forming sills, dykes or lava flows may display a magnetic anisotropy derived from the viscous flow during their emplacement. We model a sill as a steady-state flow of a Bingham fluid, driven by a pressure gradient in a horizontal conduit. The magma velocity as a function of depth is calculated from the motion and constitutive equations. Vorticity and strain rate are determined for a reference system moving with the fluid. The angular velocity and the orientation of an ellipsoidal magnetic grain immersed in the fluid are calculated as functions of time or strain. Magnetic susceptibility is then calculated for a large number of grains with a uniform distribution of initial orientations. It is shown that the magnetic lineation oscillates in the vertical plane through the magma flow direction, and that the magnetic foliation plane changes periodically from horizontal to vertical. The results are compared with the magnetic fabric of Ferrar dolerite sills (Victoria Land, East Antarctica) derived from low-field susceptibility measurements. Text Antarc* Antarctica East Antarctica Victoria Land HighWire Press (Stanford University) East Antarctica Victoria Land Bingham ENVELOPE(-63.400,-63.400,-69.400,-69.400) Geophysical Journal International 128 1 230 240 |
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English |
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Articles Dragoni, Michele Lanza, Roberto Tallarico, Andrea Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
topic_facet |
Articles |
description |
Volcanic rocks forming sills, dykes or lava flows may display a magnetic anisotropy derived from the viscous flow during their emplacement. We model a sill as a steady-state flow of a Bingham fluid, driven by a pressure gradient in a horizontal conduit. The magma velocity as a function of depth is calculated from the motion and constitutive equations. Vorticity and strain rate are determined for a reference system moving with the fluid. The angular velocity and the orientation of an ellipsoidal magnetic grain immersed in the fluid are calculated as functions of time or strain. Magnetic susceptibility is then calculated for a large number of grains with a uniform distribution of initial orientations. It is shown that the magnetic lineation oscillates in the vertical plane through the magma flow direction, and that the magnetic foliation plane changes periodically from horizontal to vertical. The results are compared with the magnetic fabric of Ferrar dolerite sills (Victoria Land, East Antarctica) derived from low-field susceptibility measurements. |
format |
Text |
author |
Dragoni, Michele Lanza, Roberto Tallarico, Andrea |
author_facet |
Dragoni, Michele Lanza, Roberto Tallarico, Andrea |
author_sort |
Dragoni, Michele |
title |
Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
title_short |
Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
title_full |
Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
title_fullStr |
Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
title_full_unstemmed |
Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica) |
title_sort |
magnetic anisotropy produced by magma flow: theoretical model and experimental data from ferrar dolerite sills (antarctica) |
publisher |
Oxford University Press |
publishDate |
1997 |
url |
http://gji.oxfordjournals.org/cgi/content/short/128/1/230 https://doi.org/10.1111/j.1365-246X.1997.tb04083.x |
long_lat |
ENVELOPE(-63.400,-63.400,-69.400,-69.400) |
geographic |
East Antarctica Victoria Land Bingham |
geographic_facet |
East Antarctica Victoria Land Bingham |
genre |
Antarc* Antarctica East Antarctica Victoria Land |
genre_facet |
Antarc* Antarctica East Antarctica Victoria Land |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/128/1/230 http://dx.doi.org/10.1111/j.1365-246X.1997.tb04083.x |
op_rights |
Copyright (C) 1997, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.1997.tb04083.x |
container_title |
Geophysical Journal International |
container_volume |
128 |
container_issue |
1 |
container_start_page |
230 |
op_container_end_page |
240 |
_version_ |
1766264521627795456 |