Dennis Geist's Home Page

I am a professor of geology at the University of Idaho. I specialize in the study of volcanoes and volcanic rocks, especially in the Galapagos Islands and the inland northwest of the United States.

Link to materials from the 2011 Chapman Conference, held in the Galápagos.

If you're thinking about coming here for grad school, check out my page dedicated to present and former Grad Students in Petrology and Volcanology.

Chronicles and results from the Galapagos Geodetic and Gravity Grid.


Recent Publications

PDFs of many of the reprints are at:

Chadwick, WW, Jónsson, S, Geist, DJ, Poland, M, Johnson, DJ, Batt, S, Harpp, KS, and Ruiz, A, The May 2005 eruption of Fernandina volcano, Galápagos: The first circumferential dike intrusion observed by GPS and InSAR, Bulletin of Volcanology 73, 679-697, 2011.

Gibson, SA and Geist, D, Geochemical and geophysical estimates of lithospheric thickness variation beneath Galápagos, Earth and Planetary Science Letters 300, 275-286, 2010.

Kurz, MD; Curtice, J; Fornari, D; Geist, D; Moreira, M.. Primitive neon from the center of the Galapagos hotspot. Earth and Planetary Science Letters. 286 23-34, 2009.

Geist, D. and Harpp, K, Galapagos Islands, Geology, Encyclopedia of Islands, Gillespie and Clague, eds. University of California Press, 367-372, 2009.

Herbert, S, Gibson, S, Norman, D, Geist, D, Estes, G, Grant, T, and Miles, A, Into the field again: Re-examining Charles Darwin’s 1835 geological work on Isla Santiago (James Island) in the Galapagos Archipelago, Earth Sciences History 28, 1-31, 2009.

Garcia, MO, Ito, G, Weis, D, Geist, D, et al., Widespread secondary volcanism near northern Hawaiian Islands, Eos 89, 542-543, 2008.

Vigouroux, N.,Williams-Jones, G., Chadwick, W., Geist, D., Ruiz, A., and Johnson, D., 4D gravity changes associated with the 2005 eruption of Sierra Negra volcano, Galápagos, Geophysics 73,29-35 , 2008.

Geist, D., Dieffenbach, B., Fornari, D, Kurz, M, Harpp, K., and Blusztajn, J., Construction of the Galapagos platform by large submarine volcanic terraces, Geochemistry Geophysics Geosystems, 9, doi:10.1029/2007GC001795, 2008.

Geist, D, Harpp, K, Naumann, T, Poland, M, Chadwick, W, Hall, M, and Rader, E, The 2005 eruption of Sierra Negra volcano, Galápagos, Bulletin of Volcanology, 70, 655-673, 2008.

Mayhew, L., Geist, D., Childers, and Pierson, J., Microbial community comparisons as a function of the physical and geochemical conditions of the Galapagos Island fumaroles, Geomicrobiology Journal, 24, 615-625, 2007.

A.E. Saal, M.D. Kurz, S.R. Hart, J.S. Bluszta, J. Blichert-Toft, Y. Liang and D.J. Geist, 2007, The role of lithospheric gabbros on the composition of Galapagos lavas, Earth and Planetary Science Letters v. 257, 391-406.

Lyons,  J, Geist, D, Harpp, K, Diefenbach, B, Olin, P, and Vervoort, J, Crustal growth by magmatic overplating in the Galápagos, Geology v. 35, 511-514, 2007.

Geist, D, Fornari, D, Kurz, M, Harpp, K, Soule, SA, Perfit, M, and Koleszar, A, Submarine Fernandina: A magmatic plumbing system at the leading edge of the Galapagos Hotspot Geochemistry Geophysics Geosystems, v. 7, DOI 10.1029/2006GC001290, 2006.

Chadwick, WW, Geist, D., Jonsson, S, Poland, M, Johnson, D and Meertens, C, Volcano bursting at the seams: Inflation, faulting, and eruption at Sierra Negra volcano, Galapagos, Geology 34, 1025-1028, 2006.

Geist, D., Chadwick, WW, and Johnson, D, Results from new GPS And Gravity Monitoring Networks at Fernandina and Sierra Negra Volcanoes, Galápagos,  2000-2002, Journal of Volcanology and Geothermal Research 150, 79-97, 2006.

Courses I Teach

I teach:
Geology 326: Igneous and Metamorphic Petrology
Geology 101: Physical Geology
Geology 546: Physical Petrology
Geology 467/567: Volcanology

Course materials are now at:

Other stuff

Curriculum Vitae

This is a slightly outdated copy of my resume, including publications.


I have several seminar talks for colleges and universities, and each year I visit local schools to talk about volcanoes.

Some Cool Links

The Journal of Petrology

The leading journal of hard-rock geology.

Lucky Lab Brew Pub
Go have a beer at my brother's tavern in Portland.

Mickey's Optic Stuff
Take the spindle stage for a ride.
Little Kennie Rubins has things about stuff, some great isotope geochemistry, and you can even ask him a question!
Geology Department Home Page

UI Home Page

Background of this page is a photomicrograph of a nicely cumulate gabbro.

Last updated: October, 2011 or thereabouts