Late glacial to Recent stratigraphy, paleontology, and sedimentary processes: Newfoundland continental slope and rise

Abstract

Micropaleontology, pollen, sediment, and δ18O studies point to considerable variation in sedimentary processes and water-mass characteristics on the northeast Newfoundland slope and rise during late glacial and Holocene time. Allochthonous shelf and upper slope foraminiferal species suggestive of turbidity current activity occur relatively frequently in rise sediments during a postglacial interval, dated by extrapolation from a probable 9300 year old ash horizon. A single late glacial turbidity current deposit involved a much larger volume of sediment than that noted for the earlier events and it appears to have originated primarily on the middle slope. In conjunction with a widespread late glacial interval of fecal pellet deposition, this larger event suggests an increased flux of material in the form of suspended particulate matter to the continental margin following the late Wisconsinan glacial maximum. Oceanographic conditions during late glacial time appear to have stimulated the productivity of zooplankton in the waters off northeastern Newfoundland.Within the late Holocene interval of the rise sediments, there is some micropaleontological and sedimentological evidence for an intensification of the Western Boundary Undercurrent that appears to have started about 1000–2000 years BP. Over the same period of time, the surface water circulation seaward of the northeast Newfoundland shelf appears to have changed from a mode that was dominated occasionally by a northern component of relatively warm North Atlantic drift water to one that is dominated today exclusively by Labrador Current water.