The Santa Rosa - Calico Volcanic Field: A Case Study of Magmatic Processes Associated with the Yellowstone Hotspot and Lithospheric Extension

Miami University, Oxford OH

Investigators

Abstract

Hart 0106144 This project is an integrated field, geochronologic, geochemical, and petrologic investigation of circa 17 to13 Ma volcanism associated with the initial late Cenozoic manifestations of the Yellowstone-Newberry hotspot system and with lithospheric extension in the Nevada - Oregon border region. The area under investigation, the Santa Rosa-Calico volcanic field, lies within the northwestern projection of a major late Miocene continental rift regime and is located between two other Oregon Plateau volcanic fields that typically are identified with the emergence of the Yellowstone-Newberry hotspot system. The field and analytical strategy is designed to provide a comprehensive view of the Santa Rosa-Calico volcanic field. Techniques to be employed include GPS/GIS assisted field mapping; air photo and satellite remote sensing interpretations; petrographic, chemical and isotopic characterization of eruptive products and petrogenetic processes; and absolute eruptive history assessment via Ar-Ar age determinations. Using the Santa Rosa-Calico volcanic field as a case study this research will test and provide new constraints on hypotheses for [1] the origin of intermediate magmas in extensional settings, [2] the role of basaltic magmatism in the formation and evolution of evolved magmas, [3] the role of crustal melting and open system differentiation processes in the evolution of compositionally diverse magmatic suites, and [4] the role that pre- and syn-magmatic extension plays in controlling the location, eruptive style(s), and compositional diversity of multi-vent volcanic fields.