Base metal exploration of the mount read volcanics, Western Tasmania: PT. III. application of lead isotopes at Elliott Bay.

Lead isotope studies were carried out in the southern part of the Mount Read Volcanics on rock chip, drill core, and bed-rock geochemical samples in order to improve the genetic model of mineralization and to assign exploration priorities. Samples analyzed from 20 separate mineralized occurrences fall into three major isotopic groups which correspond to three different styles and episodes of mineralization. Lead isotope data for all samples of mineralization and volcanics studies can be interpreted in a multistage model to imply an ultimate source for the lead from the Precambrian basement. The ratios of massive sulfide mineralization at Elliott Bay are distinctly less radiogenic than for massive sulfide mineralization farther north in the Mount Read Volcanics at Rosebery and Que River and this implies the possibility of different ages for the separate mineralizing systems or a variation in the U-Th-Pb characteristics of source regions along the volcanic belt.