Late Quaternary sedimentation in central Flemish Pass

Abstract

Flemish Pass is a basin in 1000 m water depth on the continental slope off the Grand Banks of Newfoundland and has a Quaternary fill principally of turbidites. The late Quaternary history of the pass has been investigated using mid-range side-scan sonargraphs, high-resolution seismic profiles, and cores dated using C-14. The sequence of facies in the cores reveals six lithostratigraphic units deposited in the past 40 ka. At 15–19 ka and ?25–30 ka, sedimentation was dominated by debris-flow and turbidite deposits, together with hemipelagic deposits of similar clay-size mineralogy, derived from the Grand Banks. At other times, ice-rafting and hemipelagic sedimentation, principally of carbonate-rich sediment transported by the Labrador Current, predominated. A late Quaternary regional unconformity on the slope may reflect the effects of ice sheets reaching the shelf break, probably in the Early Wisconsinan. Late Wisconsinan resedimentation was not related to ice-marginal processes and probably resulted from iceberg impacts.