1. Earth and Planetary Sciences; Rutgers University; Piscataway New Jersey USA
2. Lamont-Doherty Earth Observatory of Columbia University; Palisades New Jersey USA
3. Geological Survey of Canada; Ottawa Ontario Canada
4. Geosciences Research Division, Scripps Institution of Oceanography, University of California, San Diego; La Jolla California USA
5. Department of Earth Sciences “Ardito Desio,”; University of Milan; Milan Italy
6. Alpine Laboratory of Paleomagnetism; Cuneo Italy
7. Department of Earth and Atmospheric Sciences; University of Alberta; Edmonton Alberta Canada