USING MACROFOSSILS FROM CLEAR CREEK TO RECONSTRUCT LANDSCAPES IN IOWA

Studying fossil seeds is a reliable way to reconstruct previous landscapes. These macrofossils were preserved in silts exposed on the banks of Clear Creek and identified to reconstruct the surrounding landscape and vegetation. The enclosing sediments and soils in the exposure were studied to determine the date of approximate age of the macrofossils. The seeds from three separate cutbanks were washed through screens and identified by comparing them with seeds in the modern seed collection. The first site contained large numbers of Larix and Picea needle fragments, suggesting that this site represented a conifer forest similar to those found in northern Minnesota today. The second site contained Ceratophyllum and Potamogeton as major constituents suggesting a former wetland. The third site had primarily seeds of weedy open ground plants, including a non-native species, suggesting a relatively recent age.