Paleoprecipitation Climate Model

archived

The project is to document a 13,000-year history of rainfall in Idaho's Salmon River basin from freshwater river mussel and land snail shell carbonate stable isotopes. Freshwater mussels and snails absorb water and incorporate the oxygen into their shell. The water they absorb therefore reflects the entire basin. The ratio of isotopes in the water reflects changes in precipitation. A past precipitation model will be developed by conducting stable isotope analyses (18-Oxygen) on freshwater river mussel and land snail shells recovered from archaeological sites along the lower Salmon River. Close interval (10 mm) samples of shell carbonate will be taken along mollusk growth axes, and these subsamples will be submitted for isotope analysis. The results of isotope analyses will be compared against modern freshwater and terrestrial mollusk isotope signatures to establish subdecadal scale proxy climate records of paleoprecipitation. Age control for the isotope record will be established by direct radiocarbon dating of each sampled mollusk shell. Statistical analysis of the assembled isotope records will be used to define patterns and trends in the paleoprecipitation record. This project meets the criteria for the CESU arrangements.

High