Magnetic mineral transport and sorting in the swash-zone: Northern Lake Erie

Eric Gallaway, University of Windsor


A study was conducted along the coast of Point Pelee National Park in northern Lake Erie to address uncertainties over the sediment transport of fine magnetic minerals (< 250 micrometres) in the swash zone. Magnetic tracers (magnetite) were tracked with a magnetic susceptibility meter, and for comparative purposes, fluorescent tracers were also used to track the movement of two sizes (< 250 micrometres and > 250 micrometres) of non-magnetic grains (quartz and calcite). Despite higher threshold shear stresses and settling velocities than for the coarse non-magnetic tracers, movement of the magnetic tracers was much slower and less prolonged, with the magnetic tracers eventually being buried and deposited into the upper foreshore. The results suggest, under low to moderate wave energy conditions, magnetic grains remain below the surface in the swash zone and do not contribute to the net sediment transport, and only move during high energy wave conditions.