Palaeomagnetic study of the Lorne Plateau Lavas, Scottish Caledonides: two emplacement episodes of normal polarity during the Pridoli-Lochkovian and a precisely dated Siluro-Devonian pole position


Piper, JDA ORCID: 0009-0002-4376-5081, Kokelaar, BP and Roberts, AP (2025) Palaeomagnetic study of the Lorne Plateau Lavas, Scottish Caledonides: two emplacement episodes of normal polarity during the Pridoli-Lochkovian and a precisely dated Siluro-Devonian pole position. Geological Magazine, 162. e6-. ISSN 0016-7568, 1469-5081

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Abstract

<jats:title>Abstract</jats:title> <jats:p>The Lorne Plateau lava succession of the north-west Grampian Highlands of Scotland is an early component of post-collisional Late Silurian to Early Devonian magmatism in the Orthotectonic Caledonides emplaced in two phases between the Late Silurian (425.0±0.7 Ma U-Pb zircon) and the Siluro-Devonian boundary at ∼419 Ma. Palaeomagnetic study comprising thermal demagnetization and component analysis embracing the time frame of the preserved succession yields a coherent mean direction of magnetization from 58 sites (D/I = 43.7/−47.4°, <jats:italic>α</jats:italic><jats:sub>95</jats:sub> = 4.0°). A palaeomagnetic fold test is significantly positive with sills intruding unlithified sediment on the island of Kerrera confirming primary remanence. The ∼600 m thick succession has uniform normal polarity throughout permitting correlation with the beginning of a normal polarity chron extending from ∼426 to 403 Ma. The pole position at 2.7°N, 317.3°E (<jats:italic>dp</jats:italic>/<jats:italic>dm</jats:italic> = 3.8/5.8°) predicts a palaeolatitude of 26°S and corresponds precisely with remanence in contemporaneous rocks from the Midland Valley of Scotland. Regional palaeofield directions are evaluated in the context of transpressional moulding of the Acadian Orogeny on the Great Glen Fault system (~416−380 Ma).</jats:p>

Item Type: Article
Uncontrolled Keywords: 37 Earth Sciences, 3705 Geology, 3706 Geophysics
Divisions: Faculty of Science and Engineering
Faculty of Science and Engineering > School of Environmental Sciences
Depositing User: Symplectic Admin
Date Deposited: 07 Feb 2025 11:35
Last Modified: 07 Feb 2025 13:58
DOI: 10.1017/s0016756824000463
Open Access URL: https://doi.org/10.1017/S0016756824000463
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3190186
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