Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin
Volcanic passive margins (VPMs) are characterized by large volumes of melt emplaced within the lithosphere during break-up processes. Several data and a recently proposed conceptual model of volcanic margin development suggest that VPMs are fed from localized crustal zones of magma storage, underlyi...
Published in: | Geophysical Journal International |
---|---|
Main Authors: | , |
Format: | Text |
Language: | English |
Published: |
Oxford University Press
2004
|
Subjects: | |
Online Access: | http://gji.oxfordjournals.org/cgi/content/short/159/2/816 https://doi.org/10.1111/j.1365-246X.2004.02426.x |
id |
fthighwire:oai:open-archive.highwire.org:gji:159/2/816 |
---|---|
record_format |
openpolar |
spelling |
fthighwire:oai:open-archive.highwire.org:gji:159/2/816 2023-05-15T16:03:42+02:00 Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin Callot, Jean-Paul Geoffroy, Laurent 2004-11-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/159/2/816 https://doi.org/10.1111/j.1365-246X.2004.02426.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/159/2/816 http://dx.doi.org/10.1111/j.1365-246X.2004.02426.x Copyright (C) 2004, Oxford University Press Volcanology Geothermics Fluids and Rocks TEXT 2004 fthighwire https://doi.org/10.1111/j.1365-246X.2004.02426.x 2013-05-26T17:39:42Z Volcanic passive margins (VPMs) are characterized by large volumes of melt emplaced within the lithosphere during break-up processes. Several data and a recently proposed conceptual model of volcanic margin development suggest that VPMs are fed from localized crustal zones of magma storage, underlying large polygenetic volcanoes localized above diapir-like instabilities of the asthenosphere. We investigated the magma flow pattern within the coast-parallel dyke swarm of the East Greenland VPM, which is the only outcropping VPM, over a distance of 125 km. The 44 sampled dykes are representative of the successive families of intrusions. Igneous petrofabrics are constrained by the measurements of the anisotropy of magnetic susceptibility. The magnetic fabrics are of medium to low anisotropy ( P ′ < 1.08) and show moderately oblate ellipsoids ( T > 0). Flow-related fabrics are recorded in 75 per cent of the sampled dykes. We infer the flow directions from the imbrication geometry of the magnetic foliation planes at the dyke margins, and check the results by measuring the preferred orientation of plagioclase in thin sections cut in the magnetic principal planes. Due to probable fabric superposition, the magnetic lineation represents the zone axis for the distribution of magnetic foliation plane. We obtained 23 reliable flow directions that are predominantly horizontal and directed away from identified crustal reservoirs. This flow pattern supports the proposed model of VPM growth, and emphasizes the localized nature of the magma sources in the mantle. The entire flood basalt sequence appears to have been fed by a restricted number of crustal reservoirs and associated dyke swarms. Text East Greenland Greenland HighWire Press (Stanford University) Greenland Geophysical Journal International 159 2 816 830 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Volcanology Geothermics Fluids and Rocks |
spellingShingle |
Volcanology Geothermics Fluids and Rocks Callot, Jean-Paul Geoffroy, Laurent Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
topic_facet |
Volcanology Geothermics Fluids and Rocks |
description |
Volcanic passive margins (VPMs) are characterized by large volumes of melt emplaced within the lithosphere during break-up processes. Several data and a recently proposed conceptual model of volcanic margin development suggest that VPMs are fed from localized crustal zones of magma storage, underlying large polygenetic volcanoes localized above diapir-like instabilities of the asthenosphere. We investigated the magma flow pattern within the coast-parallel dyke swarm of the East Greenland VPM, which is the only outcropping VPM, over a distance of 125 km. The 44 sampled dykes are representative of the successive families of intrusions. Igneous petrofabrics are constrained by the measurements of the anisotropy of magnetic susceptibility. The magnetic fabrics are of medium to low anisotropy ( P ′ < 1.08) and show moderately oblate ellipsoids ( T > 0). Flow-related fabrics are recorded in 75 per cent of the sampled dykes. We infer the flow directions from the imbrication geometry of the magnetic foliation planes at the dyke margins, and check the results by measuring the preferred orientation of plagioclase in thin sections cut in the magnetic principal planes. Due to probable fabric superposition, the magnetic lineation represents the zone axis for the distribution of magnetic foliation plane. We obtained 23 reliable flow directions that are predominantly horizontal and directed away from identified crustal reservoirs. This flow pattern supports the proposed model of VPM growth, and emphasizes the localized nature of the magma sources in the mantle. The entire flood basalt sequence appears to have been fed by a restricted number of crustal reservoirs and associated dyke swarms. |
format |
Text |
author |
Callot, Jean-Paul Geoffroy, Laurent |
author_facet |
Callot, Jean-Paul Geoffroy, Laurent |
author_sort |
Callot, Jean-Paul |
title |
Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
title_short |
Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
title_full |
Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
title_fullStr |
Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
title_full_unstemmed |
Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
title_sort |
magma flow in the east greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin |
publisher |
Oxford University Press |
publishDate |
2004 |
url |
http://gji.oxfordjournals.org/cgi/content/short/159/2/816 https://doi.org/10.1111/j.1365-246X.2004.02426.x |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland Greenland |
genre_facet |
East Greenland Greenland |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/159/2/816 http://dx.doi.org/10.1111/j.1365-246X.2004.02426.x |
op_rights |
Copyright (C) 2004, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.2004.02426.x |
container_title |
Geophysical Journal International |
container_volume |
159 |
container_issue |
2 |
container_start_page |
816 |
op_container_end_page |
830 |
_version_ |
1766399393228914688 |