CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Gravenor, C. P,
Date : 1980
Title : Heavy minerals and sedimentological studies on the glaciogenic Late Precambrian Gaskiers Formation of Newfoundland
Publication : Canadian Journal of Earth Sciences
Issue : 17(10):
Page(s) : 1331-1341
Abstract
The heavy minerals found in diamictites and intrastratal sandstone and siltstone rhythmites of the Late Precambrian Gaskiers Formation of Newfoundland are dominated by altered pyroxenes and amphiboles with lesser amounts of garnet and zircon and trace amounts of tourmaline and rutile. The garnets are angular, fresh in appearance, and about 9% of the garnets have glacially derived chattermark trails. This observation, along with the presence of striated and facetted clasts, suggest that at some time prior to final deposition, the diamictites underwent transport in glaciers which were of ice cap or ice sheet dimensions. Soft sediment deformational and rip-up structures found in both the diamictites and intercalated sediments of the Gaskiers Formation suggest that the sediments were derived from a "pile-up" of debris near the margin of a grounded glacier. The "pile-up" of debris periodically became unstable and flowed down a gentle subaqueous incline. It is suggested that an appropriate term for the diamictites would be glaciogenic subaqueous debris flows.
Bibliography of Canadian Geomorphology