EASTERN IOWA DUNE ORIENTATION AS A PROXY FOR EFFECTIVE WIND DIRECTION DURING THE LATE WISCONSINAN

The orientation of dunes in Eastern Iowa demonstrates the effective wind direction during the Late Wisconsin. The study area contains over 2,100 dune features mapped from 1m LiDAR-derived rasters and SSURGO-based parent materials. The highest concentration was found on the Iowan Erosion Surface (IES). This project derived the wind direction of over 700 parabolic dunes using their arm orientation. The resulting dataset showed a Gaussian distribution with a mean around 300 degrees (WNW). This unimodal signal indicates that there was one effective wind direction (WNW) across multiple landform regions during the active phase of dune formation. These findings supports previous research indicating a WNW wind during the Late Wisconsin in the Midwest and strengthen the transport surface interpretation of the IES.