The Quaternary sediments and seismostratigraphy of the Grand Banks of Newfoundland and the Northeast Newfoundland Shelf: Foraminiferal refinements and constraints

Benthic, planktonic and reworked foraminifera have been analysed from sediment cores and boreholes collected from the Grand Banks of Newfoundland and the Northeast Newfoundland Shelf. Twenty-three foraminiferal assemblages, delineated into six assemblage groups, have been recognized. The environments of deposition inferred from the foraminiferal assemblages refines and constrains information from seismostratigraphic interpretation and lithologic characteristics. Important glacial/deglacial/oceanographic conditions are reflected in the benthic foraminiferal faunas; changes not otherwise observed in the sediments.;Offshore ice-cover was widespread during the Wisconsinan glaciation. Evidence indicates that during deglaciation there were at least four offshore dispersal centers.;Grounded ice did not extend to the outer northern Northeast Newfoundland Shelf, but floating ice was proximal. Detrital carbonate intervals in these sediments may provide the first evidence of Heinrich layers and at least one massive meltwater discharge through Hudson Strait. Bonavista Channel, "Catalina" Basin, and Downing Basin were covered by grounded ice. The presence of the Trinity Moraine and surrounding meltwater channels, suggest meltwater radiating from a Newfoundand-centered ice cap that extended onto Northeast Newfoundland Shelf. The foraminiferal evidence of meltwater channels on southern Grand Bank, and in the near-surface on Whale Bank; and the meltwater/deglacial foraminiferal faunas in the Tail of the Bank Mud, all suggest deglaciation of a Grand Bank-centered ice cap with meltwater flowing to the south.;The sand ridges on Grand Bank formed in a mid-shelf environment in post-transgressive times. Distinct foraminiferal zonation suggests the ridges are fairly stable and have not undergone complete migration and sediment turnover. The foraminiferal content of the core of the ridges also indicates meltwater channels were wide-spread on southern Grand Bank when the transgression commenced.;There is evidence of three ice advances from the Mid-Wisconsinan through to the Younger Dryas preserved in the sediments of Halibut Channel. Seismostratigraphic evidence suggests that the two younger advances were centered offshore. Till and till-tongue sediments have been collected and studied for the first time on the western Atlantic margin, providing insights into till-tongue deposition. Foraminifera faunas have been utilized to distinguish (along with physical properties and sediment characteristics) lodgement fill from deformation till.;Constraints can be placed on the age and origin of the Hibernia Delta, an outer bank progradational coarse sediment wedge. The Delta is Mid- to Late Pleistocene in age; has a glacigenic origin, or is the product of reworking of glacigenic sediments, or was deposited by both processes.;The extent and thickness of the preserved Quaternary sedimentary record on the Grand Banks is much greater than previously believed.