RELATIONSHIP BETWEEN SEDIMENT SIZE AND MAGNETIC SUSCEPTIBILITY IN LAKE ERIE BEACH SANDS

Laboratory measurements were used to determine the grain size distribution, spatial variation, and magnetic susceptibility of sands collected from six beaches along the south shore of Lake Erie in Ohio. Magnetic susceptibility was determined through construction and calibration of a purpose-built laboratory device. Sediment samples were collected along transects from shoreline to vegetation line on each of the six study beaches for a total of 14 transects. Preliminary results from physical analysis and generalized linear mixed models indicate that magnetic susceptibility significantly differed based on grain size and location on the beach. Grain size decreased and magnetic susceptibility increased at statistically significant levels in a landward direction along the transects. Particles were also separated by size to investigate size-specific variations. Magnetic susceptibility values were driven by particles less than 250 μm and due to the natural sorting process, these grains were concentrated in the landward portion of the beaches. This supported the hypotheses that finer particles would have higher magnetic susceptibility and would be found in the lower energy regions of each beach. Comparisons of grain size and magnetic susceptibility between beaches was less conclusive and will require additional analysis in order to determine if our method for evaluating magnetic susceptibility can be used as a means for examining beach erosion at a larger scale.