Advanced

Paleomagnetic and geochronological studies on Paleoproterozoic diabase dykes of Karelia, East Finland-Key for testing the Superia supercraton

Salminen, J.; Halls, H. C.; Mertanen, S.; Pesonen, L. J.; Vuollo, J. and Söderlund, Ulf LU (2014) In Precambrian Research 244. p.87-99
Abstract
Paleomagnetic results are presented for two Paleoproterozoic mafic dykes in the Taivalkoski area in northern Karelia Province of the Fennoscandian shield where, based on K-Ar data, the crust has seen minimal effects of the otherwise pervasive 1.8-1.9 Ga Svecofennian orogeny. Within this study a new U-Pb baddeleyite age of 2339 +/- 18 Ma has been determined for one of the E-W trending dykes (dyke AD13). The paleomagnetic results show that a strong Svecofennian overprinting is pervasive in the area. Upon thermal or AF demagnetization four remanence directions were obtained. Most typical are the secondary Svecofennian remanence direction A (intermediate down to the NNW) and remanence direction B (intermediate down to the NNE). Component D (D... (More)
Paleomagnetic results are presented for two Paleoproterozoic mafic dykes in the Taivalkoski area in northern Karelia Province of the Fennoscandian shield where, based on K-Ar data, the crust has seen minimal effects of the otherwise pervasive 1.8-1.9 Ga Svecofennian orogeny. Within this study a new U-Pb baddeleyite age of 2339 +/- 18 Ma has been determined for one of the E-W trending dykes (dyke AD13). The paleomagnetic results show that a strong Svecofennian overprinting is pervasive in the area. Upon thermal or AF demagnetization four remanence directions were obtained. Most typical are the secondary Svecofennian remanence direction A (intermediate down to the NNW) and remanence direction B (intermediate down to the NNE). Component D (D = 115.4 degrees, 1=50.5 degrees, alpha(95) =2.6 degrees) yielding a virtual geomagnetic pole (VGP) D (Plat= -19.5 degrees N, Plon= 263.3 degrees, A95 = 3.1 degrees) is obtained from baked rocks for dyke WD, and based on a positive baked contact test is interpreted to represent the primary magnetization dating from about 2.4 Ga. Dyke AD13 carries only secondary A and B components, its unbaked host migmatites carry reversed A (A(R)) component, and the baked host rock carries a component D' (D = 134.5 degrees, 1= -7.3 degrees, alpha(95) = 8.8 degrees), which yields a VGP pole D' (Plat= -20.4 degrees N, Plon = 257.3 degrees, A(95) = 7.6 degrees), possibly representing magnetization at 2.3 Ga. The new paleomagnetic data from the Karelia Province compared to similar-aged paleomagnetic data from the Superior Province does not support the recently proposed Superia configuration, based upon dyke swarm trajectories. (c) 2013 Elsevier B.V. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Supercontinents, Paleomagnetism, Paleoproterozoic, Superia, Karelia, Mafic dykes
in
Precambrian Research
volume
244
pages
87 - 99
publisher
Elsevier
external identifiers
  • wos:000335106900008
  • scopus:84897383151
ISSN
0301-9268
DOI
10.1016/j.precamres.2013.07.011
language
English
LU publication?
yes
id
6dbca41a-9a1a-4ffa-ac32-6ba2d6a97144 (old id 4482550)
date added to LUP
2014-06-19 14:34:31
date last changed
2017-06-25 03:19:25
@article{6dbca41a-9a1a-4ffa-ac32-6ba2d6a97144,
  abstract     = {Paleomagnetic results are presented for two Paleoproterozoic mafic dykes in the Taivalkoski area in northern Karelia Province of the Fennoscandian shield where, based on K-Ar data, the crust has seen minimal effects of the otherwise pervasive 1.8-1.9 Ga Svecofennian orogeny. Within this study a new U-Pb baddeleyite age of 2339 +/- 18 Ma has been determined for one of the E-W trending dykes (dyke AD13). The paleomagnetic results show that a strong Svecofennian overprinting is pervasive in the area. Upon thermal or AF demagnetization four remanence directions were obtained. Most typical are the secondary Svecofennian remanence direction A (intermediate down to the NNW) and remanence direction B (intermediate down to the NNE). Component D (D = 115.4 degrees, 1=50.5 degrees, alpha(95) =2.6 degrees) yielding a virtual geomagnetic pole (VGP) D (Plat= -19.5 degrees N, Plon= 263.3 degrees, A95 = 3.1 degrees) is obtained from baked rocks for dyke WD, and based on a positive baked contact test is interpreted to represent the primary magnetization dating from about 2.4 Ga. Dyke AD13 carries only secondary A and B components, its unbaked host migmatites carry reversed A (A(R)) component, and the baked host rock carries a component D' (D = 134.5 degrees, 1= -7.3 degrees, alpha(95) = 8.8 degrees), which yields a VGP pole D' (Plat= -20.4 degrees N, Plon = 257.3 degrees, A(95) = 7.6 degrees), possibly representing magnetization at 2.3 Ga. The new paleomagnetic data from the Karelia Province compared to similar-aged paleomagnetic data from the Superior Province does not support the recently proposed Superia configuration, based upon dyke swarm trajectories. (c) 2013 Elsevier B.V. All rights reserved.},
  author       = {Salminen, J. and Halls, H. C. and Mertanen, S. and Pesonen, L. J. and Vuollo, J. and Söderlund, Ulf},
  issn         = {0301-9268},
  keyword      = {Supercontinents,Paleomagnetism,Paleoproterozoic,Superia,Karelia,Mafic dykes},
  language     = {eng},
  pages        = {87--99},
  publisher    = {Elsevier},
  series       = {Precambrian Research},
  title        = {Paleomagnetic and geochronological studies on Paleoproterozoic diabase dykes of Karelia, East Finland-Key for testing the Superia supercraton},
  url          = {http://dx.doi.org/10.1016/j.precamres.2013.07.011},
  volume       = {244},
  year         = {2014},
}