Hafnium-Isotopic Time Series in Iron-Manganese Crusts: A Comparison Between (Hf and (Nd Variations David, K. ; Frank, M. ; Belshaw, N. S. ; O'Nions, R. K. Abstract Publication: Ninth Annual V. M. Goldschmidt Conference Pub Date: August 1999 Bibcode: 1999nag..conf.7163D