Volatilization experiments on U decay chain nuclides and Th involving the addition of CaCl2 to a basanite and heating sequentially at 1300 ¿C were performed. The results indicate loss of 210Pb with Na and K at low Cl concentrations and 226Ra with Fe at considerably higher Cl concentrations. 238U, 230Th and 232Th were not lost by volatilization even at the highest Cl concentrations. ¿ American Geophysical Union 1991