Pollen, plant macrofossils and microvertebrates from mid-Holocene alluvium in east-central Iowa, USA: Comparative taphonomy and paleoecology

A variety of taphonomic processes can strongly influence the composition of fossil assemblages. This paper compares the taphonomic framework for each fossil group, interprets the paleoecologic signal from each, and then compares the three interpretations. Pollen and plant macrofossils are found in organic silts, indicating deposition in a quiet water environment. Microvertebrates ordinarily occur in sand-sized sediments and show evidence of fluvial transport. Despite these different pathways, all Lilienthal assemblages indicate that a largely closed mesic deciduous forest grew along Mud Creek in mid-Holocene time. Therefore, a narrow north-south ecotone must have existed between the forest and tall-grass prairie biomes in eastern Iowa. This robust data set provides a detailed picture of the paleoecology and paleogeography of this past environment.