Maryjo Brounce
University of California-Riverside, CA·Earth & Environmental Science
Hawaii's volcanoes sit far from any boundary between tectonic plates, yet their lavas show a surprisingly wide range of oxidation state, a measure of how much oxygen is chemically available in the magma. Some Hawaiian lavas resemble those from mid-ocean ridges, where new seafloor forms.
- Fields
Earth & Environmental Science
- Topics
Hawaii
basalt
magma
- Grants
- 1 known grant, through May 2027
What they work on
- Measure Fe3+/Fe2+ and S6+/S2- ratios in Hawaiian basaltic glasses using synchrotron XANES (X-ray absorption near edge structure spectroscopy) to determine each magma's oxidation state.
- Separate the effects of crustal processes such as crystallization from mantle source differences by correcting XANES-based oxygen fugacity for igneous differentiation.
- Combine new redox measurements with existing element and isotope data to test whether oxidized Hawaiian magmas come from heterogeneous mantle that may carry recycled subducted material.
- Work with the Natural History Museum to rescue at-risk geologic samples relevant to understanding variation in Earth's upper mantle.
More about the research
Others resemble lavas from subduction zones, where ocean crust sinks back into the mantle. Is this spread caused by volcanic processes in the crust beneath Hawaii, or by differences in the deep mantle source? The answer bears on whether plate tectonics drives a whole-Earth oxygen cycle, and on whether Earth's upper mantle is uniform or patchy in oxidation state.
Why it matters
The work adds basic understanding of how Earth's interior works: whether the upper mantle varies in oxidation state, and whether plate tectonics recycles oxygen through the whole planet. These results could eventually inform models of mantle convection, plate tectonics and how Earth formed and differentiated.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Michael Hudak
Williams College, MA·Earth & Environmental Science
Measure nitrogen, hydrogen, and noble gas abundances in exposed lower crustal and upper mantle rocks of the Jurassic Talkeetna arc, Alaska, to estimate how much volatile material the lower arc crust stores.
Kevin Konrad
Oregon State University, OR·Earth & Environmental Science
Determine when the Manihiki and Hikurangi Plateaus formed, how long that took, and whether eruptions came in pulses, using high-resolution 40Ar/39Ar dating of their lavas.
Esteban Gazel
Cornell University, NY·Earth & Environmental Science
Reconstruct pre-eruptive magma conditions, volatile saturation and degassing pathways of basaltic Plinian eruptions using olivine-hosted melt inclusions, droplets of melt trapped during crystal growth.
The school
University of California-Riverside: 21 labs on PI Pages, $232M a year on research, 328 research doctorates a year.
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