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A paleomagnetic and U-Pb geochronology study of the western end of the Grenville dyke swarm: Rapid changes in paleomagnetic field direction at ca. 585 Ma related to polarity reversals?

Halls, Henry C.; Lovette, Alan; Hamilton, Mike and Söderlund, Ulf LU (2015) In Precambrian Research 257. p.137-166
Abstract
A paleomagnetic study of the western end of the similar to 585 Ma Grenville dyke swarm shows that individual dykes are characterized by high coercivity and unblocking temperature magnetizations that can differ in direction by as much as 90 degrees. Field tests including baked contact studies and the continuity of paleomagnetic direction along dyke strike, suggest that the magnetizations are primary. Precise U-Pb baddeleyite dating on these dykes indicates that changes in magnetization direction of similar to 90 degrees occur in less than 4 million years, and their close temporal association with reversals of the axial dipole field suggest that certain dykes are recording an equatorial dipole field as a transitional field between opposite... (More)
A paleomagnetic study of the western end of the similar to 585 Ma Grenville dyke swarm shows that individual dykes are characterized by high coercivity and unblocking temperature magnetizations that can differ in direction by as much as 90 degrees. Field tests including baked contact studies and the continuity of paleomagnetic direction along dyke strike, suggest that the magnetizations are primary. Precise U-Pb baddeleyite dating on these dykes indicates that changes in magnetization direction of similar to 90 degrees occur in less than 4 million years, and their close temporal association with reversals of the axial dipole field suggest that certain dykes are recording an equatorial dipole field as a transitional field between opposite polarity states. The documented instability in the Earth's field occurs less than 10 Myr before the first recorded appearance of macroscopic multi-cellular organisms on Earth, inviting speculation that an extended period of frequent magnetic reversals may play a part in faunal evolution. (C) 2014 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Neoproterozoic, Grenville dyke swarm, Paleomagnetism, U-Pb baddeleyite, geochronology, Magnetochronology, Faunal evolution
in
Precambrian Research
volume
257
pages
137 - 166
publisher
Elsevier
external identifiers
  • wos:000349586300010
  • scopus:84919897406
ISSN
0301-9268
DOI
10.1016/j.precamres.2014.11.029
language
English
LU publication?
yes
id
984f2150-9a0c-4487-b46e-67613f654e2e (old id 5176029)
date added to LUP
2015-03-25 13:23:17
date last changed
2017-10-22 03:07:37
@article{984f2150-9a0c-4487-b46e-67613f654e2e,
  abstract     = {A paleomagnetic study of the western end of the similar to 585 Ma Grenville dyke swarm shows that individual dykes are characterized by high coercivity and unblocking temperature magnetizations that can differ in direction by as much as 90 degrees. Field tests including baked contact studies and the continuity of paleomagnetic direction along dyke strike, suggest that the magnetizations are primary. Precise U-Pb baddeleyite dating on these dykes indicates that changes in magnetization direction of similar to 90 degrees occur in less than 4 million years, and their close temporal association with reversals of the axial dipole field suggest that certain dykes are recording an equatorial dipole field as a transitional field between opposite polarity states. The documented instability in the Earth's field occurs less than 10 Myr before the first recorded appearance of macroscopic multi-cellular organisms on Earth, inviting speculation that an extended period of frequent magnetic reversals may play a part in faunal evolution. (C) 2014 Elsevier B.V. All rights reserved.},
  author       = {Halls, Henry C. and Lovette, Alan and Hamilton, Mike and Söderlund, Ulf},
  issn         = {0301-9268},
  keyword      = {Neoproterozoic,Grenville dyke swarm,Paleomagnetism,U-Pb baddeleyite,geochronology,Magnetochronology,Faunal evolution},
  language     = {eng},
  pages        = {137--166},
  publisher    = {Elsevier},
  series       = {Precambrian Research},
  title        = {A paleomagnetic and U-Pb geochronology study of the western end of the Grenville dyke swarm: Rapid changes in paleomagnetic field direction at ca. 585 Ma related to polarity reversals?},
  url          = {http://dx.doi.org/10.1016/j.precamres.2014.11.029},
  volume       = {257},
  year         = {2015},
}