Contourite or Turbidite Magnetic Fabric of Fine-Grained Quaternary Sediments, Nova Scotia Continental Rise

摘要

Samples of three piston cores and one gravity core from the Nova Scotia continental rise (depths 4210-4925 m) have been examined to differentiate parallel-to-slope and downslope depositional processes in Quaternary deposits from a region presently influenced by a strong contour current. Measurement of anisotropy of magnetic susceptibility of samples of a red-brown, silt-laminated luite 'contourite' facies shows grain alignments which are consistent with both parallel-to-slope (contour current) flow and downslope (turbidity current) flow. The authors believe that these results provide support for the hypothesis that 'geologically significant' contour currents have influenced continental rise deposition during the pleistocene. However, our observation that both alongslope and downslope alignments are present in lithologically similar units clearly demonstrates the need for studies on the relationship between lithofacies and process in this geological setting.