[1] ETH, Inst Isotope Geol & Min Resources, CH-8006 Zurich, Switzerland
[2] Univ Cologne, Inst Geol Min, D-5000 Cologne, Germany
[3] Forsch Inst Senckenberg, Frankfurt, Germany
[4] Fordham Univ, Dept Chem, New York, NY 10023 USA
[5] Am Mus Nat Hist, New York, NY USA