Paleomagnetism and geochemistry of Carboniferous Sandwich Bay dykes from coastal Labrador

Abstract

Paleomagnetic, petrographic, and geochemical data are used to characterize a suite of dykes in the Sandwich Bay area, south of Cartwright, Labrador. These dykes are Carboniferous in age and their separate identity is indicated by the following: (i) distinct paleomagnetic signatures, (ii) homogeneous geochemistry, (iii) cross-cutting relations with other dated rock units in the area, and (iv) a whole-rock K–Ar date of 327 ± 13 Ma.The dikes have a soft present Earth's field component superposed on a stable magnetization at D = 325.5°, I = −26.9 °(N = 14, k = 91.6, α95 = 4.6°) with the corresponding paleopole at 16.2°N, 157.6°E (dp, dm = 2.8°, 5.2°). The stable magnetization is shown to be primary from baked contact tests. No Kiaman overprint is present. The paleopole determined for the dykes suggests emplacement of the dykes at equatorial latitudes during the Carboniferous times.