1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
2. Hydroisotop, 85301 Schweitenkirchen, Germany
3. Universidade Federal Do Ceará, 60450 Fortaleza, Ceará, Brazil
4. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA, and Department of Geological Sciences, Columbia University, New York, NY 10027, USA.
5. Institut für Mittelenergiephysik, Eidgenössische Technische Hochschule, CH-8093 Zürich, Switzerland