At Yucca Mountain, calcite occurs as open-space fillings and coatings on fractures within much of the host volcanic rocks in both the saturated and unsaturated zones. Strontium isotope analyses of these calcites divide the samples into two groups corresponding to their location in either the saturated or unsaturated zones. The group of samples from the unsaturated zone corresponds very well with pedogenic carbonate samples, indicating that the strontium came from the surface during infiltration events. However, four samples from the unsaturated zone show strontium isotopic ratios similar to present-day ground water. Since these samples are closest to the water table, they are interpreted as the result of a higher water-table stand (approx.85 m higher than present-day) in the past.
Additional publication details
Strontium isotopic evidence for a higher water table at Yucca Mountain
Publ by ASCE
New York, NY, United States
Larger Work Title:
High Level Radioactive Waste Management
Proceedings of the 4th Annual International Conference on High Level Radioactive Waste Management