Sedimentology and sequence stratigraphy of the Paleoproterozoic Rove and Virginia Formations, southwest Superior Province

The Paleoproterozoic Rove and Virginia Formations are lithostratigraphically and chronostratigraphically correlative units which comprise the upper sedimentary strata in the Animikie basin. They sharply overlie an intensely altered zone within the upper Gunflint and Biwabik iron formations which was subaerially exposed by compressional forces during the Penokean Orogeny. Dating of volcaniclastic zircons from the upper Gunflint yielded a pre-Penokean age of 1878 Ma. Tuffaceous layers very near the base of the Rove and Virginia Formations provided U-Pb zircon ages of approximately 1835 Ma placing commencement of sedimentation into the newly resubmerged basin during the final stages of Penokean igneous activity.; This study involved examination of 3200 m of drill core from eleven continuously drilled holes and one twiced drilled hole extending over 424 km from south of Duluth to south of Thunder Bay. Observation of the lithofacies present and their stratigraphic relationships provided insight into the depositional environment as well as the tectonic regime operating at the time. (Abstract shortened by UMI.)...