MÖSSBAUER STUDIES OF ICELANDIC LAVAS Ö. HELGASON, S. STEINTHORSSON, S. MØRUP, J. LIPKA and J. E. KNUDSEN J. Phys. Colloques, 37 C6 (1976) C6-829-C6-832 DOI: 10.1051/jphyscol:19766174