Abstract

Paleomagnetic results are reported for the first time from the coast of Labrador. The rocks are from (1) 20 sites of gently folded basalts of the Mugford Series, dated 948 ± 90 m.y., near Cape Mugford, and (2) 12 gabbroic dikes in a swarm dated 2080 ± 42 m.y., near Indian Harbour. Both dates are from preliminary, published K–Ar determinations. After partial alternating-field (AF) or thermal demagnetization, nearly all samples from both rock units revealed a stable thermoremanence that is most probably of primary origin. For the Mugford basalts, a mean remanence direction relative to bedding planes was calculated, after AF treatment, from 16 stably magnetized sites (graphic flows). The corresponding pole is 49 °N, 143 °W, with dp = 9°, dm = 11°, which is northeastward of most North American poles from rocks dated 1200-1000 m.y. The pole calculated from the 12 Indian Harbour dikes, after AF treatment, is 6 °S, 117 °W, with dp = 6°, dm = 12°.

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