Paleomagnetism of the Scourie Dykes, Lewisian Foreland, NW Scotland: Constraints on Early Paleoproterozoic Paleogeography of Kenorland

Abstract

The Scourie dyke swarm in the Lewisian foreland of northwest Scotland provides key constraints on the Paleoproterozoic evolution of the North Atlantic craton. High‐precision U‐Pb geochronology identifies two distinct intrusive phases at ∼2.41–2.38 Ga and ∼2.00 Ga. However, despite decades of work, the regional paleomagnetic record remains sparse and is often compromised by Laxfordian overprints, leaving the position of the Lewisian within early Proterozoic reconstructions equivocal, thereby motivating our paleomagnetic study and a re‐evaluation of paleogeography. We report new paleomagnetic data from 17 dated dykes, including the first positive baked‐contact tests for this region, demonstrating that primary remanent magnetizations are preserved despite later Laxfordian metamorphism. Both the ∼2.4 Ga and ∼2.0 Ga dyke suites record dual‐polarity mean directions, with Dec = 133.6°, Inc = −79.1°, α ₉₅  = 10.1°, and k  = 45.2 for the ∼2.4 Ga suite, and Dec = 277.4°, Inc = 50.2°, α ₉₅  = 7.0°, and k  = 174.8 for the ∼2.0 Ga suite, consistent with high‐ and mid‐paleolatitude emplacements, respectively. The new data support possible paleogeographic scenarios: at ∼2.4 Ga, the Lewisian may have occupied a near‐polar position, close to Dharwar‐Bastar craton of India and Yilgarn craton of Australia, probably forming a large landmass at high paleolatitudes, and by ∼2.0 Ga, it had moved to subtropical latitudes and most likely amalgamated with Laurentia in the north. This dual‐age record highlights the transition from the breakup of the Kenorland supercontinent and emphasizes the Lewisian foreland as a keystone in early Proterozoic supercontinent reconstructions.