Abstract

A paleomagnetic study has been carried out on 75 samples of metagabbro and metaperidotite from 14 sites in the Labrador Trough. The sites were distributed over a distance of 500 km and are situated in sills intruded into formation near the top of the trough stratigraphic column. Four components (A, B, C, and D) were obtained after alternating field (AF) and thermal demagnetization. The mean directions of magnetization are A. 143°, +33°. α95 = 14.4°. k = 15.4, 8 sites: B, 69°, +51°, α95 = 10.3d, k = 22.9, 10 sites: C. 278°. +15°, α95 = 7.7°, k = 28, 14 sites; and D, 200°, +16°. α95 = 13.3°, k = 16.2, 9 sites. All components are secondary. The fold test is negative, and consequently no primary magnetization has been preserved in the isolated components. Component C may have erased all others in zones of highest metamorphism. The paleopoles obtained for components D, A, and C are, respectively, 270°E. 23°S (δP = 10°. δm = 18°); 327°E, 9°S (δp = 11°. δm = 20°); and I9°E, 11°S (antipole) (δp = 10°. δm = 17°). The paleopole positions obtained for these three components are compared with me existing late Aphebian and early Paleohelikian apparent polar wander (APW) path for North America and fall in the 1750–1850 Ma interval.

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