Paleomagnetism of Archean volcanics and Proterozoic dikes in La Grande Riviere area of Nouveau-Quebec
Paleomagnetic results are reported for six Archean volcanics and six Proterozoic diabase dike sites in the La Grande Riviere basin using AF and thermal demagnetization. The area is now flooded so that future work is not possible. The limited geological and statistical data base makes interpretation of the results necessarily tentative. The dikes yield an A component pole at 84°W, 74°N from magnetization residing in higher stability domains, which likely reflects emplacement either at ~2150 or ~1825 or ~1650 Ma ago, and a B component pole at 33°W, 4°S residing in lower stability domains, which likely reflects metamorphism during the Hudsonian Orogeny at ~1725 Ma, or, less likely, during Grenvillian uplift at ~975 Ma. The volcanics appear to yield a prefolding C component pole at 28°W, 49°S that dates extrusion at ~2900 Ma and a postfolding D component pole at 306°W, 37°N that dates metamorphism by the Kenoran Orogeny at ~2600 Ma.