Jeremy Hietala HBSc thesis abstract

Thesis Title: 
Bar Formation on the Sub-Aqueous Sand Sheet of the Gravel River Delta, Lake Superior

The formation of sand bars located on a deltaic sand shelf was investigated.  The sand bars are oriented in three separate directions, one set forms parallel to the shelf edge, one set forms lengthwise in a north to south orientation, and the last set forms lengthwise in an east to west orientation.  All three sets form in a relatively small area.  The transition from deep water to the shelf occurs quickly, and the shelf edge to the shoreline remains relatively flat.  The profiles for the sand bars show that the ones that form along the edge of the sand shelf are asymmetrical.  Thus, they are probably formed by breaking waves, while the bars that form in the interior of the shelf are symmetrical and form after the breaking waves have reformed.  Examining wind direction and speed data shows that the dominant wind direction is from the west and would support the formation of waves travelling in the directions needed for the bar formation.  The grainsize distribution for the transition from deep-water to the shoreline and beach indicates a coarsening trend as the water becomes shallower.  There is a high percentage of a suspension population in the deep-water samples, while the samples obtained across the sand shelf and the beach are dominantly a saltation population.