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Precise U-Pb baddeleyite ages of mafic dykes and intrusions in southern West Greenland and implications for a possible reconstruction with the Superior craton

Nilsson, Mimmi K. M.; Söderlund, Ulf LU ; Ernst, Richard E.; Hamilton, Michael A.; Scherstén, Anders LU and Armitage, Paul E. B. (2010) In Precambrian Research 183(3). p.399-415
Abstract
The Archaean block of southern Greenland constitutes the core of the North Atlantic craton (NAC) and is host to a large number of Precambrian mafic intrusions and dyke swarms, many of which are regionally extensive but poorly dated. For southern West Greenland, we present a U-Pb zircon age of 2990 +/- 13 Ma for the Amikoq mafic-ultramafic layered intrusion (Fiskefjord area) and four baddeleyite U-Pb ages of Precambrian dolerite dykes. Specifically, a dyke located SE of Ameralik Fjord is dated at 2499 +/- 2 Ma, similar to a previously reported Ar-40/Ar-39 age of a dyke in the Kangamiut area. For these and related intrusions of ca. 2.5 Ga age in southern West Greenland, we propose the name Kilaarsarfik dykes. Three WNW-trending dykes of the... (More)
The Archaean block of southern Greenland constitutes the core of the North Atlantic craton (NAC) and is host to a large number of Precambrian mafic intrusions and dyke swarms, many of which are regionally extensive but poorly dated. For southern West Greenland, we present a U-Pb zircon age of 2990 +/- 13 Ma for the Amikoq mafic-ultramafic layered intrusion (Fiskefjord area) and four baddeleyite U-Pb ages of Precambrian dolerite dykes. Specifically, a dyke located SE of Ameralik Fjord is dated at 2499 +/- 2 Ma, similar to a previously reported Ar-40/Ar-39 age of a dyke in the Kangamiut area. For these and related intrusions of ca. 2.5 Ga age in southern West Greenland, we propose the name Kilaarsarfik dykes. Three WNW-trending dykes of the MD3 swarm yield ages of 2050 +/- 2 Ma, 2041 +/- 3 Ma and 2029 +/- 3 Ma. A similar U-Pb baddeleyite age of 2045 +/- 2 Ma is also presented for a SE-trending dolerite (Iglusuataliksuak dyke) in the Nain Province, the rifted western block of the NAC in Labrador. We speculate that the MD3 dykes and age-equivalent NNE-trending Kangamiut dykes of southern West Greenland, together with the Iglusuataliksuak dyke (after closure of the Labrador Sea) represent components of a single, areally extensive, radiating swarm that signaled the arrival of a mantle plume centred on what is presently the western margin of the North Atlantic craton. Comparison of the magmatic 'barcodes' from the Nain and Greenland portions of the North Atlantic craton with the established record from the north-eastern Superior craton shows matches at 2500 Ma, 2214 Ma, 2050-2030 Ma and 1960-1950 Ma. We use these new age constraints, together with orientations of the dyke swarms, to offer a preliminary reconstruction of the North Atlantic craton near the north-eastern margin of the Superior craton during the latest Archaean and early Palaeoproterozoic, possibly with the Core Zone craton of eastern Canada intervening. (C) 2010 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Geochronology, U-Pb, baddeleyite, Superior, Reconstruction, North Atlantic craton, Nain
in
Precambrian Research
volume
183
issue
3
pages
399 - 415
publisher
Elsevier
external identifiers
  • wos:000285233200005
  • scopus:78449300863
ISSN
0301-9268
DOI
10.1016/j.precamres.2010.07.010
language
English
LU publication?
yes
id
14c8ad47-07c5-4f2e-a125-0bdc4a7a625d (old id 1772383)
date added to LUP
2011-02-02 20:47:36
date last changed
2018-06-17 03:37:36
@article{14c8ad47-07c5-4f2e-a125-0bdc4a7a625d,
  abstract     = {The Archaean block of southern Greenland constitutes the core of the North Atlantic craton (NAC) and is host to a large number of Precambrian mafic intrusions and dyke swarms, many of which are regionally extensive but poorly dated. For southern West Greenland, we present a U-Pb zircon age of 2990 +/- 13 Ma for the Amikoq mafic-ultramafic layered intrusion (Fiskefjord area) and four baddeleyite U-Pb ages of Precambrian dolerite dykes. Specifically, a dyke located SE of Ameralik Fjord is dated at 2499 +/- 2 Ma, similar to a previously reported Ar-40/Ar-39 age of a dyke in the Kangamiut area. For these and related intrusions of ca. 2.5 Ga age in southern West Greenland, we propose the name Kilaarsarfik dykes. Three WNW-trending dykes of the MD3 swarm yield ages of 2050 +/- 2 Ma, 2041 +/- 3 Ma and 2029 +/- 3 Ma. A similar U-Pb baddeleyite age of 2045 +/- 2 Ma is also presented for a SE-trending dolerite (Iglusuataliksuak dyke) in the Nain Province, the rifted western block of the NAC in Labrador. We speculate that the MD3 dykes and age-equivalent NNE-trending Kangamiut dykes of southern West Greenland, together with the Iglusuataliksuak dyke (after closure of the Labrador Sea) represent components of a single, areally extensive, radiating swarm that signaled the arrival of a mantle plume centred on what is presently the western margin of the North Atlantic craton. Comparison of the magmatic 'barcodes' from the Nain and Greenland portions of the North Atlantic craton with the established record from the north-eastern Superior craton shows matches at 2500 Ma, 2214 Ma, 2050-2030 Ma and 1960-1950 Ma. We use these new age constraints, together with orientations of the dyke swarms, to offer a preliminary reconstruction of the North Atlantic craton near the north-eastern margin of the Superior craton during the latest Archaean and early Palaeoproterozoic, possibly with the Core Zone craton of eastern Canada intervening. (C) 2010 Elsevier B.V. All rights reserved.},
  author       = {Nilsson, Mimmi K. M. and Söderlund, Ulf and Ernst, Richard E. and Hamilton, Michael A. and Scherstén, Anders and Armitage, Paul E. B.},
  issn         = {0301-9268},
  keyword      = {Geochronology,U-Pb,baddeleyite,Superior,Reconstruction,North Atlantic craton,Nain},
  language     = {eng},
  number       = {3},
  pages        = {399--415},
  publisher    = {Elsevier},
  series       = {Precambrian Research},
  title        = {Precise U-Pb baddeleyite ages of mafic dykes and intrusions in southern West Greenland and implications for a possible reconstruction with the Superior craton},
  url          = {http://dx.doi.org/10.1016/j.precamres.2010.07.010},
  volume       = {183},
  year         = {2010},
}