Sedimentary analysis of a sag pond at Fairfield Osborn Preserve

Towers et al 2014; James et al 2014 - We visited the Fairfield Osborn Preserve to analyze the stratigraphy of the sag pond, located on the Rodgers Creek fault, and infer past environmental changes. Students took soil samples along a 25 meter transect using soil augers. Three locations were sampled within the sag pond and a comparative sample was taken outside of the pond. The samples were taken in 10 cm increments to approximately 50 cm in depth. The class performed loss on ignition, macrofossil, pH, grain size analysis, magnetic susceptibility, and Munsell color evaluation on the soil samples in the lab. Preliminary investigation showed distinct changes in soil color and texture with depth and macrofossil charcoal, suggesting changes in environment over time and the presence of fire in the region. We hope to correlate these changes in stratigraphy with long-term sedimentary processes resulting from mass wasting and tectonic activity.