J. Michael Rhodes

Mike Rhodes is the director of the Ronald B. Gilmore X-ray Analytical Facility. He has been involved with the geological application of XRF analyses for almost 30 years. Following early training in Australia by Bruce Chappell and Keith Norrish, he established and operated an XRF laboratory at the NASA Manned Spacecraft Center in Houston. This laboratory was responsible for the initial analyses of the returned lunar samples, meteorites and terrestrial materials. On coming to UMass in 1978, he established the Ronald B. Gilmore X-ray Analytical Facility.

Mike in the shade in Chile.

Mike in the heat in Hawaii.

Research on lunar samples, particularly the lunar mare basalts, led to an interest in using geochemical data to understand volcanic and magmatic processes on earth, including ocean-floor basalts, the association of coeval mafic and silicic magmas and Hawaiian lavas. Current research is focussed on the long-term magmatic evolution of Mauna Loa, Kilauea and Mauna Kea volcanoes on the assumption that such studies are germane to an understanding of the scale, composition, dynamics, and processes of magma generation, movement and accumulation within the Hawaiian plume. Specific problems being addressed include:- What can be learned about the parental magmas of these volcanoes, and what are the implications for the source components? Is there a correlation between magma supply rate and magma composition and type on Mauna Loa? If so, have there been major temporal changes in Mauna Loa magma compositions, particularly about 10 ka ago, or have the magmas remained relatively unchanged over 150 ka or more? What do very old (÷ 200 ka?) submarine picritic Mauna Loa lavas tell us about source components and early Mauna Loa magmatism? What happened on Kilauea between 200 and 0.4 ka when "Mauna Loa-like" lavas were erupted? Was this a unique event, and if so, was it source-related or a consequence of magma invasion from Mauna Loa?

Sea kayaking off the coast of Hawaii.

Rhodes is also an editor for the Journal of Petrology. With Jack Lockwood he is the co- project leader for the Mauna Loa Decade Volcano Project, and recently edited the AGU Monograph "Mauna Loa Revealed: Structure, Composition, History and Hazards", a contribution to the Decade Volcano Project. Rhodes analyzed cores recovered from the pilot drill-hole of the "Hawaiian Scientific Drilling Project", and expects to be overwhelmed by cores from the 4.5 km drill hole that will hopefully result from the continuation of this project. When not thinking about volcanoes and geochemistry, there is a very good chance that he can be found backcountry skiing, sea kayaking or designing lingerie.

Click here to see Mike's other 'official' Geosciences Department homepage.

A Selection of Recent Publications:

Rhodes, J. M., C. Morgan and R.A. Liias, Geochemistry of Axial Seamount lavas: Magmatic relationship between the Cobb Hotspot and the Juan de Fuca Ridge, J. Geophys. Res. 95, 12713- 12733, 1990.

Garcia, M. O., J. M. Rhodes, E. W. Wolfe, G. E. Ulrich and R. A. Ho, Petrology of lavas from episodes 2-47 of the Puu Oo eruption of Kilauea Volcano, Hawaii, Bull. Volcanol., 55, 1-16, 1992.

Chapman, M. and J. M. Rhodes, Composite layering in the Isle au Haut Igneous Complex, Maine: Evidence for periodic invasion of a mafic magma in an evolving magma chamber, J. Vol. and Geotherm. Res. 51, 41-60, 1992.

Frey, F. A. and J. M. Rhodes,Intershield geochemical differences among Hawaiian volcanoes: Implications for source compositions, melting processes and magma ascent paths, Roy. Soc. London Phil. Trans., A342, 121-136, 1993.

Rhodes, J. M. and S. R. Hart, Episodic trace element and isotopic variations in historical Mauna Loa lavas: Implications for magma and plume dynamics, in Mauna Loa Revealed: Structure, Composition, History and Hazards, Geophys. Monogr. Ser. 92, p.263-288, edited by J. M. Rhodes and J. P. Lockwood, AGU, Washington, D.C., 1995.

Rhodes, J. M., The 1852 and 1868 Mauna Loa picrite eruptions: Clues to parental magma compositions and the magmatic plumbing system, in Mauna Loa Revealed: Structure, Composition, History and Hazards, Geophys. Monogr. Ser. 92, p.241-262, edited by J. M. Rhodes and J. P. Lockwood, AGU, Washington, D.C., 1995.

Rhodes, J. M., The Geochemical Stratigraphy of lava flows sampled by the Hawaii Scientific Drilling Project, J.Geopys. Res., 101, 11,729-11,746, 1996.