Mid-Eocene renewal of magmatism in NW Scotland the Loch Roag Dyke, outer hebrides

Amonchquite 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 Ar-40/Ar-39 plateau age of 45.2 +/- 0.2 Ma (2 sigma) of a phlogopite megacryst from...

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Bibliographic Details
Published in:Journal of the Geological Society
Main Authors: Faithfull, J. W., Timmerman, Martin Jan (Dr.), Upton, B. G. J., Rumsey, M. S.
Format: Article in Journal/Newspaper
Language:English
Published: 2012
Subjects:
Institut für Geowissenschaften
Greenland
East Greenland
North Atlantic
Online Access:https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36083
https://doi.org/10.1144/0016-76492011-117
Description
Summary:Amonchquite 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 Ar-40/Ar-39 plateau age of 45.2 +/- 0.2 Ma (2 sigma) 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.

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