Sequence Stratigraphy, Provenance, Isotopic Composition, and Regional Correlation of the Upper Hornby Bay and Lower Dismal Lakes Groups, NWT and Nunavut.

摘要

Late Paleoproterozoic uraniferous basins of Canada's north including the Thelon, Athabasca, and Hornby Bay, can be broadly correlated based on similarities in age, sequence stratigraphy, paleocurrents and detrital zircon provenance. In this-drill core based study, detailed sequence stratigraphy was analyzed in the upper Hornby Bay (UHG) to lower Dismal Lakes groups (LDG) (Hornby Bay Basin, Nunavut). Sedimentary provenance was examined using Sm-Nd isotopes from siliciclastic mudstones and stable C and O isotopes were analyzed on carbonates within the Hornby Bay Group. Sequence stratigraphy identified a major unconformity between the Hornby Bay and Dismal Lakes Groups. Results from Sm-Nd analyses identified two important sources for sediment, the Thelon-Taltson Magmatic Zone (TMZ) and the Great Bear Magmatic Zone (GMZ). Stable isotopes are in the range of delta13C between -1.5 ‰ and 0.5 ‰ VPDB, and were interpreted to represent a primary seawater value. Results from this study support the correlation of the Hornby Bay Basin with other Proterozoic basins within Canada. In particular, the Wernecke Supergroup of the Wernecke Mountains, Yukon is identified as the distal equivalent of the UHG and together they comprise a westward deepening intracratonic basin.