Mid-Eocene renewal of magmatism in NW Scotland: the Loch Roag Dyke, Outer Hebrides

• Published in: Journal of the Geological Society
• Main Authors: Faithfull, J.W., Timmerman, M.J., Upton, B.G.J., Rumsey, M.S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2012
• Subjects: Greenland; East Greenland; North Atlantic
• Online Access: http://eprints.gla.ac.uk/60700/; https://doi.org/10.1144/0016-76492011-117

A monchquite dyke, in the vicinity of Loch Roag, Lewis, Outer Hebrides has an unusually enriched chemistry, and contains a unique assemblage of megacrysts and xenoliths from the lithosphere of the Hebridean craton. A 40Ar/39Ar plateau age of 45.2 ± 0.2 Ma (2σ) of a phlogopite megacryst from the dyke overlaps an earlier reported K–Ar age, and confirms that the British Palaeogene Igneous Province extended into the Eocene. Similar late low-volume melts were erupted in the Eocene and Oligocene in West and East Greenland, suggesting that such late-stage magmatic rejuvenescence is a widespread feature across the North Atlantic Igneous Province.