Galena Lead Isotope Model for Vancouver Island*

This paper demonstrates how a galena lead isotope model can be used to make decisions about the age and origin of ore deposits on Vancouver Island. To build this model we draw on the galena data of Table 1-9-1 (compare Andrew and Godwin, in press a, b, c and Godwin et al., 1988). Galena lead isotope data from Vancouver Island do not show a systematic evolution with time. Therefore they cannot be interpreted using existing lead isotope models [for example, Stacey and Kramers (1975), Doe and Zartman (1979), Godwin and Sinclair (1982), and Andrew et al. (1984)]. Godwin ef al. (1988) have drawn attention to the need for terrane-specific models for lead isotope interpretation. The model presented here is applicable to Wrangellia, of which Vancouver Island is a part.