FOSSIL DIATOM RECORD FROM A PROGLACIAL LAKE IN INDIANA

A set of sediment samples were collected from a 17-meter long core near Brush Creek, southeast of Columbus, Indiana. These samples were dated using radiocarbon techniques to between ~25,000 and ~24,000 years before present and they are thought to be the remnants of part of an ancient proglacial lake that extended from the front of the Laurentide Ice Sheet. Here we present further evidence that the samples represent a lake environment through analysis of fossil diatoms recovered from the sediments. Diatoms are highly sensitive environmental indicators in lakes and because the skeletons are composed of silica that does not decompose, they are often preserved in lake sediments. Multiple diatom species are present in the sediment samples including genera such as Staurosirella, Mastogloia, and Amphora. Further research is being conducted to determine if possible novel species are present at sample site.