Determination of radiogenic isotopes (RbSr, SmNd and PbPb) in fluid inclusion waters: An example from the Bluebell Pb-Zn deposit, British Columbia, Canada

Abstract Rb, Sr, Pb, Nd and Sm isotopes were determined in fluid inclusion waters extracted from quartz samples of the Bluebell Pb-Zn deposit, British Columbia. The results demonstrate that radiogenic isotopes in fluid inclusion waters can constitute useful geochronological and genetic tools when applied in conjunction with geological, geochemical and other geochronological studies. Rb Sr isotopes of fluid inclusion waters and of mineralized marbles hosting the deposit indicate a Tertiary mineralization age of 19.2 ± 5.9 Ma, and an initial 87 Sr 86 Sr ratio of 0.7143. This Rb Sr date is in general agreement with a Cenozoic age suggested by geologic field relations described by Irvine (1957) and Fyles (1967). Pb isotope data suggest two isotopically distinct fluids, one less radiogenic and similar to values measured on galenas, and the other more radiogenic. This is in agreement with Ohmoto and Rye's (1970) hypothesis of two-meteoric-hydrothermal fluids, and Lecouteur's (1973) convection cell model. Nd and Sm isotope also suggest mixing of fluids. Both Pb Pb and Nd Sm data suggest very old lower and upper crustal materials as possible source of the metals.