9418889 Kurz Preliminary data from the Galapagos demonstrate the importance of helium to understanding mantle processes. Although the high 3He/4He ratios alone are important, the focus of this project is to understand the local variations, and relate them to processes within the plume. A particularly important aspect of the proposed work is that cosmic ray produced 3He can be used to determine ages, thus providing age control. This will be an integrated approach that will combine field work, major and trace element measurements, and the isotopes of He, Sr, Nd and Pb, with chronology provided by surface exposure dating. This work will be carried out in collaboration with Dennis Geist (University of Idaho) who has a long record of field work in the Galapagos. The goals of the proposed research are to: 1. Evaluate the temporal evolution of Galapagos hotspot, and individual volcanic centers using surface exposure dating. By obtaining the geochemical data in conjunction with chronology to rigorously test the various models for the overall gradients within the archipelago it should be possible. 2. Document the helium isotopic variability within the archipelago.
