[Holtz] Pre-eruptive conditions of the volcanic rocks from Snake River Plain, Yellowstone Hotspot-Constraints from experiments and phase equilibria modelling
German Title: Pre-eruptive conditions of the volcanic rocks from Snake River Plain, Yellowstone Hotspot-Constraints from experiments and phase equilibria modelling
Current Status: completed with report
Main Applicant:Prof. Dr. Francois Holtz
Prof. Dr. Jürgen Koepke
The planed ICDP drilling in the Snake River Plain volcanic province (westem United States) is aimed to trace .the Snake River Plain - Yellowstone (SRPY) hotspot and its interaction with the lithosphere. This province represents one of the best examples of a thermal anomaly related to hotspot volcanism within the continental lithosphere. Over the last 15 Ma, the SRPY-hotspot migrated ca. 600 km eastwards resulting in a bimodal (rhyoliticbasaltic) magmatism. Understanding the interaction ofthe SRPY-hotspot with the lithosphere requires information on the evolution of chemistry, sources, differentiation and storage conditions of both the rhyolitic and basaltic magmas with time and space. The proposed project is a contribution to the determination of magma storage conditions and differentiation processes in the SRPY-province. This information is gained (1) from the chemical analysis of natural minerals and glasses combined with (2) high pressure experimental studies to determine phase equilibria and (3) thermodynamic modeling. In this continuation proposal we report our preliminary results (after 12 months of the running project) on crystallization experiments with rhyolite from Bruneau-Jarbidge eruptive center (Cougar Point Tuff). Our preliminary results indicate the rhyolites were extremely dry and that pre-emptive temperatures were lower than previously suggested. Magma storage conditions and differentiation processes of basaltic lavas from two localities (Boise River and Kimama Butte) will be constrained using thermodynamic phase equilibria models.
Almeev, Renat R., Bolte, Torsten, Nash, Barbara P., Holtz, François, Erdmann, Martin, Cathey, Henrietta E. (2012). "High-temperature, low-H2O Silicic Magmas of the Yellowstone Hotspot: an Experimental Study of Rhyolite from the Bruneau–Jarbidge Eruptive Center, Central Snake River Plain, USA" Journal of Petrology p1837-1866
Botcharnikov, R. E., Almeev, R. R., Koepke, J., Holtz, F. (2008). "Phase Relations and Liquid Lines of Descent in Hydrous Ferrobasalt—Implications for the Skaergaard Intrusion and Columbia River Flood Basalts" Journal of Petrology 49 p1687-1727