1. Geological Institute, Univ. of Copenhagen; Øster Voldgade 10 1350 Copenhagen K Denmark
2. Geological Survey of Denmark and Greenland; Øster Voldgade 10 1350 Copenhagen K Denmark
3. Environment and Resources; Technical Univ. of Denmark; Building 204 2800 Lyngby Denmark
4. USGS; 12201 Sunrise Valley Drive Reston VA 20192 USA