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Ulf Söderlund

Ulf Söderlund

Professor

Ulf Söderlund

Mesoproterozoic dykes in the Timmiarmiit area, Southeast Greenland : evidence for a continuous Gardar dyke swarm across Greenland’s North Atlantic Craton

Author

  • A. Bartels
  • Mimmi Nilsson
  • M. B. Klausen
  • U. Söderlund

Summary, in English

During the Proterozoic, several mafic dykes with variable trends and mineralogies intruded the Archaean basement of Southeast Greenland. Some of the younger ENE-trending dykes are interpreted to represent a prolongation of the Mesoproterozoic Gardar Province, and have been termed Timmiarmiit dykes. Extrapolations of their trends across the inland ice sheet coincide with the northernmost so-called brown dykes (BD’s) which are part of the Gardar Province. Baddeleyite U–Pb ID-TIMS analyses for three ENE-trending Timmiarmiit dykes give ages of 1277 ± 4, 1275 ± 3 and 1268 ± 4 Ma, which are slightly younger than the oldest (BD0 = 1284–1279 ± 3 Ma, Upton 2013) and only dated generation of dykes in the Gardar Province, and thereby indirectly provide a possible age for the two younger dyke generations (BD1 and BD2). The Timmiarmiit–Gardar correlation is strengthened by a rigorous multivariate statistical analysis, on the basis of all major and trace elements. Thus, a coherent ENE-trending trans-Greenlandic dyke swarm is constituted. The major and trace element data of the Timmiarmiit dykes show that they crystallised from comparably evolved mantle-derived magma with minor crustal contamination and indicate a strong contribution of a metasomatised subcontinental lithospheric mantle component in the evolution of melts. This component was probably influenced by supra-subduction zone metasomatism during the Palaeoproterozoic Ketilidian orogeny. The data presented here, in addition to recent plate reconstruction models, give new evidence for a petrogenetic link between rift-related Mesoproterozoic magmatism in North America, South Greenland and Central Scandinavia which possibly formed in response to back-arc basin formation.

Department/s

  • Lithosphere and Biosphere Science

Publishing year

2016-01-02

Language

English

Pages

255-275

Publication/Series

GFF

Volume

138

Issue

1

Document type

Journal article

Publisher

Taylor & Francis

Topic

  • Geology

Keywords

  • dyke swarms
  • Gardar Province
  • geochemistry
  • geochronology
  • SCLM
  • South East Greenland

Status

Published

ISBN/ISSN/Other

  • ISSN: 1103-5897