One hundred and twenty-seven oriented samples of the Dubawnt Group were collected from 32 sites (10 sites in igneous rocks and 22 in sedimentary rocks) along the shores of Baker Lake, Northwest Territories (mean location of sampling sites 64.1° N., 094.7° W.). The age of the rocks is in the range 1,720 to 1,735 m.y. Demagnetization studies, the observed consistency between igneous and sedimentary rocks, the presence of reversals, and the evidence from baked contacts indicate that the magnetization was acquired at or very soon after formation. The mean direction of magnetization, irrespective of sign, is 347°, −50° (α95 = 7°), and the corresponding pole is 07° N., 083° W. (α95 = 8°). This result, together with others recently obtained, suggests that relative to North America the pole followed a westerly track in the eastern Pacific Ocean during the middle Proterozoic. These rocks are not very different in age from the Sudbury Irruptive, and the results therefore allow a tentative reconstruction of the original attitude of the northern limb of the irruptive.

First Page Preview

First page PDF preview
You do not currently have access to this article.