K. V. Ragnarsdottir, A. J. Kemp, S. R. Gislason, A. Andresdottir and T. Thorvaldsson
Department of Geology, University of Bristol, Bristol BS8 1RJ, UK
Science Institute, University of Iceland, Dunhagi 3, Reykjavik 107, Iceland
Department of Geology, University of Hawaii, Honoloulou, Hawaii, USA