GPR IMAGING OF A STRANDPLAIN ALONG LAKE SUPERIOR: HURON MOUNTAINS, MICHIGAN, USA

The subsurface stratigraphy of a strandplain along the Huron Mountains, Marquette County, Michigan, was studied using ground penetrating radar (GPR). A 600m long shore perpendicular GPR transect started at the present Lake Superior shoreline and ended at the Nipissing level beach ridge. A pulseEKKO100 GPR system was utilized with 100 MHz antennae, 1.0m antennae separation, and a step size of 0.25m. A topographic dataset was surveyed using a Topcon RL-H3CL laser level to geometrically correct the GPR profiles. The collected GPR data was processed with pulseEKKO software using trace-to-trace and down-the-trace averaging, dewow, and automatic gain control. The profile was then plotted in wiggle trace format to show the subsurface stratigraphy of the strandplain. Preliminary results indicate that the lakeward inclined strandplain is progradational with periods of stillstand. The results help us to better understand how Lake Superior shorelines have developed during a period of lake level drop.