Abstract

Twenty-nine oriented cores have been collected from six sites in the Michikamau Intrusion in Labrador. This had previously been well dated at 1400 m.y. by the potassium–argon method. A fold test has been applied to the paleomagnetic results after alternating magnetic field demagnetization. The results suggest that the magnetization was acquired with the rocks in their present attitudes. The stability of the magnetization has been well tested and it is concluded that the observed magnetization is thermo-remanent and represents the direction of the earth's field at the intrusion at the time of its formation. The paleomagnetic pole position for the intrusion lies at 0.5° S, 144.7° W, with A95 = 5.6°. It is difficult to compare this result with most other Precambrian results from North America due to uncertainties in age equivalences. However, a comparison with recently published results from well-dated rocks from Colorado–Wyoming suggests there have been no large relative movements between this region and Labrador for the last 1400 million years.

You do not currently have access to this article.