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Eclogites and basement terrane tectonics in the northern arm of the Grenville orogen, NW Scotland

Bird, A.; Thirlwall, M.; Strachan, R. A.; Millar, I. L.; Dempsey, E. D.; Hardman, K.


M. Thirlwall

R. A. Strachan

I. L. Millar

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Dr Eddie Dempsey
Senior Lecturer in Structural Geology and Geohazards

K. Hardman


The presence of eclogites within continental crust is a key indicator of collisional orogenesis. Eclogites within the Eastern Glenelg basement inlier of the Northern Highland Terrane (NHT) have been re-dated in order to provide more accurate constraints on the timing of collision within the northern arm of the Grenville Orogen. The eclogites yield dates of ca. 1200 Ma which are interpreted to record the onset of continent–continent interaction, and the NHT as a whole is thought to represent the lower plate in successive 1200–1000 Ma collision events. The Eastern Glenelg basement inlier is viewed as a fragment of the leading edge of the NHT continental basement that was partially subducted along a suture and then exhumed back up the subduction channel. Differences in ages of igneous protoliths and intrusive histories, and metamorphic events (this paper) between the NHT basement and the Laurentian foreland, suggests that they were separate crustal blocks until after ca. 1600 Ma. We therefore suggest that: (1) the NHT represents a fragment of Archean–Paleoproterozoic crust that was reworked within the ca. 1.7–1.6 Ga Labradorian-Gothian belt, although whether it was derived from Laurentia or Baltica is uncertain, and (2) amalgamation of the NHT with the Laurentian foreland did not occur until the terminal stages of the Grenville collision at ca. 1000 Ma.


Bird, A., Thirlwall, M., Strachan, R. A., Millar, I. L., Dempsey, E. D., & Hardman, K. (2023). Eclogites and basement terrane tectonics in the northern arm of the Grenville orogen, NW Scotland. Geoscience Frontiers, 14(6), Article 101668.

Journal Article Type Article
Acceptance Date Jul 1, 2023
Online Publication Date Jul 7, 2023
Publication Date Nov 1, 2023
Deposit Date Jul 6, 2023
Publicly Available Date Jul 17, 2023
Journal Geoscience Frontiers
Print ISSN 1674-9871
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 14
Issue 6
Article Number 101668
Keywords Geochronology; Eclogites; Grenville; Rodinia
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