Master of Science, University of Akron, 2015, Geology
The sediment in Rex Lake, a kettle lake in Northeast Ohio, preserves a record of modern sedimentation processes and past anthropogenic impacts to the lake and its watershed. Rex Lake is connected to a series of kettle lakes and human-made reservoirs that forms the Portage Lakes System, a popular recreational area.
Rex Lake is affected by sediment focusing processes and has a wave base of 2 m. Sands and gravels having high dry bulk density and low organic content are present in water less than 2 m deep. Organic mud and calcareous mud are present in water depths greater than 2 m. The acoustic properties of the lakefloor were used to remotely determine differences between sands/gravels and muds. Because of differences in matrix lithology and pore geometry of the organic muds and calcareous muds, this study shows that caution must be exercised when using acoustics to remotely sense lakefloor sediment grain size.
The upper 4 m of mud, from the middle of the lake, was cored and measured for physical properties, sedimentology and trace metal content. Four time periods having distinct sediment characteristics were identified and related to changing anthropogenic activities. The Pre-settlement Period characterizes organic mud below 135 cm core depth, having low sediment density, magnetic, and trace metal content. This sediment is inferred to have accumulated while the watershed was forested prior to Euro-American settlement of the area in 1805. In the Settlement Period, between 135 and 70 cm core depth, organic content decreases, magnetic content and sediment density increase slightly, and trace metal content remains low. These sediment changes are inferred to reflect increased erosion as the watershed was deforested for agricultural activities. In the Recreation Period, between 70 and 20 cm core depth, organic content decreases to its minimum value whereas the trace metal, magnetic content, and sediment density increase greatly. During this period increa (open full item for complete abstract)
Committee: John Peck Dr. (Advisor); David Steer Dr. (Committee Member); James McManus Dr. (Committee Member)
Subjects: Environmental Geology; Geology; Geophysics; History