Lead and strontium isotope ratios in metal-rich geothermal brines are compared to those of rhyolite glass from nearby rhyolite domes and also to those from Tertiary and Quaternary sediments of the area. 'The isotopic data indicate that 80-100 percent of the strontium and 50-100 percent of the lead in these brines were acquired from the associated sediments' rather than from the rhyolite. The ratios for strontium suggest that the rhyolite cannot be derived wholly from melting of sediments like those sampled.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.