Characterization and Transport of Contaminated Sediments in the Southern Central Lake Superior

Abstract

Three major source sediments were characterized and classified in terms of mineralogical and chemical composition in the west coastal area of the Keweenaw Peninsula. Bulk chemical analysis reveals that concentrations of Cu, Ag, Co, and As were enriched in metal rich mine tailings. SEM-EDS analysis indicates that the Ontonagon River sediments have high P and S concentrations. X-ray diffraction analysis of clay fraction shows that the mine tailings (chlorite rich) could be distinguished from the other two sources, Ontonagon River sediments (low chlorite and high illite) and Wisconsin red clay (low illite and high expandable phase). Local environmental conditions, i ncluding currents, bathymetry, weather conditions, and sediments texture, are important factors for cross-margin and longshore transport of contaminated sediments. The Keweenaw Current is responsible for the longshore transport of fine fraction of tailings, whereas wave action causes the lateral transport of the coarse deposits along the shore.