Susan DeBari, PhD

She/Her/Hers, Professor

Educational & Professional Experience

Ph.D. - Stanford 1990
B.A. - Cornell University 1984

Areas of Expertise

Geology:  Petrology and geochemistry. Crustal scale processes within island arcs.  The focus is to understand the physical and chemical processes that operate within and beneath volcanic arc systems both on land and beneath the sea.  What processes govern magma generation in the mantle wedge? What happens to these magmas as they traverse the Moho into arc crust?  How does this arc crust become "continent-like"? This research takes the form of study of active arc systems as well as ancient systems. I am currently involved in several major research fronts: active Cascade volcanism, deep crustal sections of ancient volcanic arcs (e.g. Baja California), and a marriage of the former fronts through research drilling expeditions in the active Izu-Bonin volcanic arc of Japan (IODP Expedition 350) and the Hellenic arc in Greece (IODP Expedition 398).

Science Education:  Using results of research on student learning to develop curricular materials for undergraduate non-science majors that foster deep learning of science and scientific practices.

Courses Taught

  • GEOL 406 Igneous and Metamorphic Petrology (field and classroom versions)
  • GEOL 309 Volcanology
  • GEOL 423/523 Advanced Igneous Petrology
  • SCED 202 Transfer of Matter and Energy in Earth Systems
  • SCED 201 Transfer of Matter and Energy in Physical Systems
  • SCED 481 Fundamentals of Teaching Science

Selected Awards and Honors

2016: Arlan Norman award for excellence in student mentoring


(* denotes WWU M.S. student author, ** denotes WWU undergrad author)

Hanuscin, D., A. Acevedo-Gutiérrez, E. Borda, S. DeBari, D. Donovan, J. Melton, T. Le, W. Morrison (2021) Supporting the Professional Development of Teacher Educators through Shadowing, International Journal of Science and Mathematics Education, v.19, p. 145-165, (invited for special issue“Science and Mathematics Teacher Educators and their Professional Growth”)

Miyazaki, T., J.B. Gill, C. Hamelin, S.M. DeBari, T. Sato, Y. Tamura, J.I. Kimura, B.S. Vaglarov, Q. Chang, R. Senda, and S. Haraguchi, 2020, The First 10 Million Years of Rear‐Arc Magmas Following Backarc Basin Formation Behind the Izu Arc. Geochemistry, Geophysics, Geosystems, v. 20, no. 10, e2020GC009114,

DeBari, S.M., *L.J. Heywood, J.B. Gill, 2020, Izu Bonin Across Arc Geochemical Dataset between latitudes 32°40' to 30°20' (IEDA),

*Heywood, L., S.M. DeBari, J. Gill, S. Straub, J. Schindlbeck-Belo, R. Escobar-Burciaga, J. Woodhead, 2020, Across-arc diversity in rhyolites from an intra-oceanic arc: Evidence from IODP Site U1437, Izu-Bonin rear-arc and surrounding area, Geochemistry, Geophysics, Geosystems. DOI:10.1029/2019GC008353

*Morris, R.A., S.M. DeBari, C.J. Busby, S. Medynski, Jicha, B., 2019, Building arc crust – plutonic to volcanic connections in an extensional island arc, the Alisitos arc crustal section, Baja California, J. Petrol., DOI: 10.1093/petrology/egz029  (  Selected as Editors choice! 

Miller, R.B., S.M. DeBari, S.R. Paterson, 2018, Construction, emplacement, and geochemical evolution of deep crustal intrusions: Tenpeak and Dirtyface plutons, North Cascades, western North America, GeosphereGS01490_Milleretal_v1_0.pdf

Gill, J.B., E.M. Bongiolo, T. Miyazaki, C. Hamelin, M. Jutzeler, S. DeBari, A-S. Jonas, B.S. Vaglarov, L.S. Nascimento, M. **Yakavonis, 2018, Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change, Geochemistry, Geophysics, Geosystems, DOI: 10.1002/2017GC007300, Gill_et_al-2017-Geochemistry%2C_Geophysics%2C_Geosystems.pdf

*Sas, M., S.M. DeBari, M. Clynne, B. Rusk, 2017, Using mineral geochemistry to decipher slab, mantle, and crustal inputs to the generation of high-Mg andesites and basaltic andesites from the northern Cascade arc, American Mineralogist, v. 102, p 948-965. (student first author)

Busby, C.J., Y. Tamura, P. Blum, G. Guèrin, G.D.M. Andrews, A.K. Barker, J.L.R. Berger, E.M. Bongiolo, M. Bordiga, S.M. DeBari, J.B. Gill, C. Hamelin, J.Jia, E.H. John, A. Jonas, M. Jutzeler, M.A.C. Kars, Z.A. Kita, K. Konrad, S.H. Mahony, M. Martini, T. Miyazaki, R.J. Musgrave, D.B. Nascimento, A.R.L. Nichols, J.M. Ribeiro, T. Sato, J.C. Schindlbeck, A.K. Schmitt, S.M. Straub, M.J. Mleneck-Vautravers, A. Yang Yang, 2017, The missing half of the subduction factory: shipboard results from the Izu rear arc, IODP Expedition 350, International Geology Review, v.59, no. 13, p. 1677-1708, Busby_IBMReararc17.pdf

DeBari, S.M, K. Gray, J. Monet, 2015, Interactions between Water, Earth’s Surface, and Human Activity, InTeGrate’s Earth-focused Modules and Courses for the Undergraduate Classroom

*Moore, N.E., S.M. DeBari, 2012, Mafic magmas from Mount Baker in the northern Cascade arc, Washington: probes into mantle and crustal processes, in press, Contributions to Mineralogy and Petrology, DOI: 10.1007/s00410-011-0686-4 (student first author) Mafic Magmas PDF version

DeBari, S.M., A. *Greene, 2011, Vertical stratification of composition, density, and inferred magmatic processes in exposed arc crustal sections, In: Brown, D., P. Ryan (eds.) Arc-continent collision, Frontiers in Earth Sciences, DOI 10.1007/978-3-540-88558-0_2, Springer-Verlag Berlin Heidelberg 2011, p. 121-144 (Invited book chapter). PDF version

*Baggerman, T.D., S. M. DeBari, 2011, The generation of a diverse suite of Late Pleistocene and Holocene basalt through dacite lavas from the northern Cascade arc at Mount Baker, Washington, Contributions to Mineralogy and Petrology, v. 161, p. 75-99, DOI: 10.1007/s00410-010-0522-2 (student first author) Late Pleistocene PDF version

*Greene, A., S. M. DeBari, P. B. Kelemen, P. D. Clift, J. Blusztajn, 2006, A detailed geochemical study of island arc crust: The Talkeetna arc section, south-central Alaska, Journal of Petrology, v. 47, no.6, p. 105-1093 (student first author). Island Arc Crust PDF version

Clift, P. D., T. Pavlis, S. M. DeBari, A. E. Draut, M. Rioux, P. B. Kelemen (2005) Subduction erosion of the Jurassic Talkeetna-Bonanza arc and the Mesozoic accretionary tectonics of western North America, Geology, v. 33, no. 11, p. 881-884.

Field, J., S. M. DeBari, M. Gallagher (2003) Promoting K-12 Community Research and Service through the Washington Earth Science Initiative,Journal of Geological Education, v. 51, no. 1, p. 54-63.

DeBari, S. M., R. G. Anderson, J. K. Mortensen (2000) Early and Middle Jurassic Magmatism:  New zircon U-Pb ages and comparative geochemistry from a crustal transect through the Bonanza arc on Vancouver Island, Canada, In: Advances in Jurassic Research 2000, Proceedings of the 5thInternational Symposium on the Jurassic System. R. L. Hall and P. L. Smith (eds), GeoResearch Forum 6, Trans Tech Publications, p. 65-76.

Miller, R. B., S. R. Paterson, S. M. DeBari, and D. L. Whitney (2000) North Cascades crustal section: changing kinematics, rheology, metamorphism, pluton emplacement, and petrogenesis from 0 to 40 km depth.  In: Guidebook for geological field trips in southwestern British Columbia and northern Washington.  G.J. Woodsworth, L.E. Jackson, Jr., J. L. Nelson, and B. C. Ward (eds), Geological Association of Canada, Cordilleran Section, Canada, p. 229-278.

DeBari, S. M., B. Taylor, K. Spencer, K. Fujioka (1999) A trapped Philippine Sea Plate origin for MORB from the inner slope of the Izu-Bonin trench, Earth and Planetary Science Letters, v. 274, no. 1-2, p. 183-197.

DeBari, S. M., R. G. Anderson, J. R. Mortensen (1999) Correlation Amongst Lower to Upper Crustal Components in an Island Arc: the Jurassic Bonanza arc, Vancouver Island, Canada, Canadian J. Earth Sciences, v. 36, p. 1371-1413.

Grissom, G. C., S. M. DeBari, L. W. Snee (1998) Geology of the Sierra de Fiambala, northwestern Argentina: Implications for Early Paleozoic Andean tectonics, in: R.J. Pankhurst and C. W. Rapela (editors), The Proto-Andean Margin of Gondwana, Geologic Society, London, Special Publications, v. 142, p. 297-323.

DeBari, S. M. (1997) Evolution of oceanic and continental arc magmas: the importance of residence in the lower crust, Canadian MineralogistSpecial Volume:  "The Nature of Primitive Magmas in Subduction Zones", v. 35, p. 501-519.

DeBari, S.M., E. P. Metzger, and R. Sedlock (1996) K-12 Teacher Education in Earth Science:  The Bay Area Earth Science Institute (BAESI), Council on Undergraduate Research Quarterly, September issue, p. 32-35.

DeBari, S. M., B. Taylor, and K. Fujioka (1995) MORB-type basalts on the inner trench wall of the Izu-Bonin trench - accreted Pacific plate or pre-existing crust? JAMSTEC Journal of Deep Sea Research, No. 11, p. 1-16. 

Sedlock, R. L., E. P. Metzger, D. R. Harden, S. M. DeBari, J. M. Mehegan, W. B. Leatham, L. A. Fernandez, and J. J. Woerner (1995) Improving Geoscience Literacy, Geotimes, June issue, p. 19-21.

DeBari, S. M. (1994) Petrogenesis and physical evolution of the Fiambalá gabbronorite, northwestern Argentina:  Syntectonic magmatism in the deep crust of a continental margin arc, Journal of Petrology, v. 35, no. 3, p. 679-713.

Coleman, R. G., S. DeBari, and Z. Peterman (1992) A-type granite and the Red Sea Opening, Tectonophysics, v. 204, no. 1/2, p. 27-40.

Grissom, G. C., S. M. DeBari, S. Page, R. Page, L. Villar, R. G. Coleman, and M. V. de Ramirez (1992) The deep crust of an early Paleozoic arc, the Sierra de Fiambalá, NW Argentina, in:  R. S. Harmon and C. W. Rapela, Andean Magmatism and its Tectonic Setting, Geological Society of America Special Paper 265, p. 189-200.

DeBari, S. M., and N. H. Sleep (1991) High-Mg, low-Al bulk composition of the Talkeetna island arc:  Implications for primary magmas and the nature of arc crust, Geological Society of America Bulletin, v. 103, p. 37-47.

Pearcy, L. G., S. M. DeBari, and N. H. Sleep (1990) Mass balance calculations for two sections of island arc crust, and implications for the formation of continents,Earth and Planetary Science Letters, v. 96, p. 427-442.

DeBari, S. M., and R. G. Coleman (1989) Examination of the deep levels of an island arc, the Tonsina Ultramafic-Mafic Assemblage, Tonsina, Alaska, Journal of Geophysical Research, v. 94, p. 4373-4391.

DeBari, S. M., S. M. Kay, and R. W. Kay (1987) Ultramafic xenoliths from Adagdak volcano, Aleutian Islands, Alaska: Deformed igneous cumulates from the Moho of an island arc, Journal of Geology, v. 95, p. 329-341.


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Science Education curricular materials

Geology and Everyday Thinking. Guided inquiry curriculum for non science majors (with 7 other authors), 319 pages (to be submitted for publication in 2019)

Acevedo-Gutierrez, A., E. Borda, S. DeBari, D. Donovan, S. Linneman (2016A Learning Cycle Approach to Guided Inquiry in a Four-Course Interdisciplinary Science Series. Innovative Teaching Showcase, 2015-2016, Western Washington University. ISSN:2374-9415. (authors in alphabetical order)

DeBari, S.M, K. Gray, J. Monet (2015) Interactions between Water, Earth’s Surface, and Human Activity, InTeGrate’s Earth-focused Modules and Courses for the Undergraduate Classroom


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Scientific Reports (non-peer reviewed)

Tamura, Y, Busby, C.J., Blum, P., and the Expedition 350 Scientists (2015Izu Bonin Mariana Rear Arc, Proceedings of the international Ocean Discovery Program, Volume 350, (includes 4 citable reports)

​Feineman, M., S. Penniston-Dorland, J. Ague, O. Bachmann, Ethan Baxter, Gray Bebout, George Bergantz, S. DeBari, H. Dick, M. Ducea, O. Jagoutz, P. Kelemen, H. Marschall, J. Ryan, B. Savage, J.N Shervais, H. Stowell, (2014) “ExTerra:  Understanding Convergent Margin Processes Through Studies of Exhumed Terranes, White Paper for the National Science Foundation GeoPrisms Program (authors in alphabetical order) 

DeBari, S.M., P. Ruprecht, S. Straub, (2013Workshop Report “Ultra-Deep Drilling Into Arc Crust: Genesis of Continental Crust in Volcanic Arcs” Waikoloa, Hawaii, September 18-21, 2012, GeoPrisms Newsletter, v. 30, p. 14-17.  (

Tamura Y., S. M. DeBari, J. Gill, S. Kodaira, (2013Workshop report: Ultradeep drilling into arc crust – genesis of continental crust in volcanic arcs, 70 pages. (


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Graduate Student Research

Recent M.S. Students

Erin Kaplan (in progress) -  Dacite magmas from Koma Kulshan volcanic field (Mount Baker), evidence for remobilization of felsic crustal mushes during eruptive episodes

Zenja Seitzinger (in progress) -  Trace elements as indicators of multiple magmatic sources to Koma Kulshan (Mount Baker) andesites over the last 50,000 years, northern Cascade arc. 

Maximilian Burnham (in progress) – Fine tuning the eruptive record of Mt. Baker, northern Cascade arc by utilizing novel methods to recognize tephra and cryptotephra from proximal lake cores.

Brendan Garvey (2022) – Using crystal zoning, thermobarometry, and MELTS to elucidate Koma Kulshan's (Mount Baker) transcrustal magma storage system,  northern Cascade Arc. Read and download thesis here: 

Cassandra King (2021) - Reidentifying the Sources of Tephra in the Izu-Bonin Arc: Recognizing Rear Arc (RASC-type) Volcanism from 1.1 – 2.7 Ma. Read and download thesis here:  

Kim Wurth (2019) - Clinopyroxene trace element chemistry as a proxy for magma compositional variation in the Izu Bonin rear-arc over the last 14 million years. Read and download thesis here:

Luan Heywood (2018) - Diversity and petrogenesis of rhyolites from an intra-oceanic arc:  Evidence from IODP site U1437, Izu Bonin rear-arc and surrounding area. Read and download thesis here: and published here:

Rebecca Morris (Summer 2017) - Building Arc Crust – Plutonic to Volcanic Connections in an Extensional Island Arc, the Alisitos Arc Crustal Section (Southern Rosario Segment), Baja California. Read and download thesis here: and published here:

Ricardo Escobar (2016) - Mineral Complexities as Evidence for Open-System Processes in Formation of Intermediate Magmas of Mount Baker Volcanic Field, Northern Cascade Arc.  Read and download thesis here:

Mai Sas (2015) - High-Mg Andesites from the Northern Cascade Arc: Using Mineral Chemistry to Distinguish Between Hypotheses for Petrogenesis.  Read and download thesis here: and reprint of American Mineralogist paper here:

Christina Stout (2015) - High-Sr Volcanic Domes from the Lassen Volcanic Region, Southernmost Cascade Arc, Northern California: Implications for Andesite and Dacite Magma Generation. Read and download thesis here: 

Angela Cota (2014) - A geochemical study of the Riddle Peaks Gabbro, north Cascades: evidence for amphibole accumulation in the mid crust of an arc. Read and download thesis here:

Julie Gross (2012) - Felsic magmas from Mt. Baker in the northern Cascade arc: origin and role in andesite production. Read and download thesis here:

Steve Shaw (2011) - H2O contents in olivine-hosted melt inclusions from primitive magmas in the Northern Cascade Arc. Read and download thesis here:

Nicole Moore (2010) - Origin and geochemical evolution of mafic magmas from Mount Baker in the northern Cascade arc, Washington: probes into mantle and crustal processes. Read and download thesis here: and published here:

Troy Baggerman (2010) - The generation of a diverse suite of Late Pleistocene and Holocene basalt through dacite lavas from the northern Cascade arc at mount Baker, Washington. Read and download thesis here:  Published here:

Ben Paulson (2010) - Magmatic Processes in the Jurassic Bonanza Arc: Insights from the Alberni Region of Vancouver Island, Canada. Read and download thesis here:


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Undergraduate Student Research

Recent Undergraduate Senior Theses

Stone Machel (Fall 2022-Spring 2023): Using trace element chemistry to elucidate magma sources to Koma Kulshan's (Mount Baker) most recent explosive eruption - the 6.7 ka Black Andesite (BA) tephra 

Holly Valgardson (Winter 2021-Spring 2022) - Mineral chemistry and thermobarometry of the 48.8 ka Swift Creek Lava flow to determine magmatic architecture beneath Koma Kulshan (Mount Baker)

Anna Johnson (Fall 2018-Fall 2019) Geochemistry of Submarine Volcanoes: Exploring Recent Petrogenesis in the Izu Rear-Arc

Larissa Sleeper (Winter 2018-Fall 2018) Chemical and Morphological Variance in Vitriclastic Shards from IODP Site U1437: Inferences about Source Regions and Eruptive Mechanisms. Read and download senior thesis here:

Maria Vasin (Fall 2017-Spring 2018) - Mount Baker Basalt Mineral Textures and Chemistry: Probes into Magma Reservoir Processes: Read and download senior thesis here: Vasin_SeniorThesis18.pdf

Erin Benson (Spring 2016) - Using clinopyroxene mineral chemistry to decipher magma compositional changes over 13 million years in the Izu-Bonin volcanic arc. Read and download senior thesis here: Benson_Thesis.pdf

Read and download poster presentation here:


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