Acknowledgements

We would like to thank Scott Charlton and Ron Antweiler, USGS, WRD, for aid with statistical analysis, Dr. Kendrick Taylor, DRI, for the use of the ECM equipment, Greg Meeker, USGS, GD, for the use of the SEM/EDA equipment, Platt Bradbury, USGS, GD for SEM pollen/diatom identification, Judy Fierstein, USGS, GD, for SEM/EDA interpretation of possible volcanic particles, Thomas Yanosky, USGS, WRD, for interpretation of the tree ring data, Mark Meier, CU, INSTAAR, for his input during the review process, and Al Bol, Geoff Hargreaves, and Joan Fitzpatrick, USGS, NICL for assistance with NICL operations.