1. Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan 48824, USA
2. Department of Earth Sciences, Addis Ababa University, Addis Ababa, Ethiopia
3. Geology Department, Pomona College, Claremont, California 91711, USA
4. Tonagharraun, Corrandulla, County Galway, Ireland
5. CEPS/NASM MRC 315, Smithsonian Institution, Washington D.C., 20013–7012, USA
6. Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260-3332, USA