1. Department of Geology; Portland State University; Portland; Oregon; USA
2. Department of the Geophysical Sciences; University of Chicago; Chicago; Illinois; USA
3. Institute for Quaternary and Climate Studies and Department of Geological Sciences; University of Maine; Orono; Maine; USA
4. Department of Physical Geography and Quaternary Geology; Stockholm University; Stockholm; Sweden
5. Department of Geology; University of Cincinnati; Cincinnati; Ohio; USA