CSEDI Collaborative Research: Joint seismic, geodynamic, and mineral physics investigation of mantle plumes

Colorado State University, Fort Collins CO

Investigators

Abstract

The concepts of hotspots and plumes have taken a central place in global geophysical and geochemical research. A common theory to explain the persistent excess volcanism at locations such as Hawaii, Iceland and Yellowstone is that they are supported by columnar upwelling of hot mantle rock called mantle plumes. Yet, these plumes have remained elusive in seismological images of the mantle. While a variety of seismological studies suggest the presence of hot anomalies below hotspot regions, a detection of a narrow whole-mantle plume has yet to be widely accepted. By combining multidisciplinary expertise, we wish to provide fundamental and quantitative tests of the plume hypothesis. We will establish answers to the following basic questions that address the physics of plume formation, morphology and longevity in Earth and the seismological resolution of plume signatures in seismic data: What are the possible plume structures given geophysical constraints? What is the expected plume signature in tomographic images? Do deep mantle plumes impart observable wave perturbations? We address these questions using a combined geodynamical, mineral physics, and seismological analysis. The proposing team forms an international collaboration between Jeroen Ritsema and Peter van Keken at Michigan, Derek Schutt at Colorado State, and Saskia Goes at London's Imperial College. We will develop new experience on establishing the structure of plumes and how they are mapped in seismological data sets. This will allow us to determine the optimal data sets and seismic techniques for mapping plumes in the mantle and to understand whether and where mantle plumes can be imaged. The grant will support the interdisciplinary education of three female graduate students and will foster an international collaboration between scientists from the US and the UK. Our Yellowstone studies may prove helpful in forthcoming EarthScope data analysis and the design of a Flexible Array deployment aimed at the Yellowstone hotspot.