Younger Dryas Boundary Field Map (IMAGE) University of Cincinnati Caption The Younger Dryas Boundary strewnfield is shown (red) with YDB sites as red dots and those by eight independent groups as blue dots. Also shown is the largest known impact strewnfield, the Australasian (purple). Credit Provided by Ken Tankersley, University of Cincinnati Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.