Professor Emeritus

Office: 541-737-1245

Wilkinson Hall

Wilkinson Hall 146

2601 SW Orchard Avenue

2601 SW Orchard Avenue
Corvallis, Oregon 97331

Profile Field Tabs

Brief Research Interests: 

Geology and geochemistry of mineral deposits, field geology



Geology and geochemistry of mineral deposits, field geology

Research Interests

Economic geology (origin of metallic mineral deposits, especially porphyry copper and related deposits of western North America and South America), structural geology, igneous petrology, stable isotopes, isotopic ages


BS Geology, California Institute of Technology, Pasadena, 1975
MS Geology, California Institute of Technology, Pasadena, 1976
PhD Geology, Stanford University, 1984


GEO 310 - Earth Materials I: Mineralogy (4 cr)
GEO 440/540 - Economic Geology (4 cr)
GEO 495 - Advanced Field Geology (6 cr)
GEO 497/597 - Field Mapping of Ore Deposits (3 cr)
GEO 516  Interpretation of Geologic Maps (3 cr)
GEO 694 - Topics in Ore Genesis (1-3 cr)

Graduate Students

(since 2010)

Michael Hutchinson (PhD, 2019)
The nature of sulfate saturation in oxidized arc magmas: implications for magmatic sulfur budgets

Jaime Osorio (MS, 2017)
Intrusion Sequence and Hydrothermal Fluid Evolution of Encuentro Porphyry Cu-Mo-Au Deposit, Northern Chile

Michael Sepp (MS, 2016)
Structural geology of the Botija porphyry deposit, Panama Cobre, Panama

Federico Cernuschi (PhD, 2015)
The Geology and Geochemistry of the Haquira East Porphyry Copper Deposit of Southern Peru: Insights on the Timing, Temperature and Lifespan of the Magmatic-hydrothermal Alteration and Mineralization: 257 p.

Elinor Utevsky (MS, 2015)
Geochemistry of plutons of the western Cascades, Washington and Oregon: Relationship to crustal segmentation and ore genesis: 131. p.

Curtis Johnson (MS, 2105)
Petrology and geochemistry of the Emigrant Pass Volcanics, Nevada: Implications for a magmatic-hydrothermal origin of the Carlin gold deposits

Nansen Olson (MS, 2015)
The Geology, Geochronology, and Geochemistry of the Kaskanak Batholith, and other Late Cretaceous to Eocene magmatism at the Pebble Porphyry Cu-Au-Mo deposit, SW Alaska

Stephanie Wafforn (MS, 2013)
Structural Geology of the Mount Polley Cu-Au District, South-Central British Columbia (co-advised with Andrew Meigs)

Lucian P. Farmer (MS, 2013)
Trace Element Characteristics of Zircon: A Means of Assessing Mineralization Potential of Intrusions in Northern Nevada (co-advised with Adam Kent)

Darrick E. Boschmann (MS, 2013)
Structural and volcanic evolution of the Glass Buttes area, High Lava Plains, Oregon (coadvised with Andrew Meigs)

Julia Cohen (MS, 2011)
Mineralogy and geochemistry of hydrothermal alteration at the Ann-Mason porphyry copper deposit, Nevada: Comparison of large-scale ore exploration techniques to mineral chemistry

Abigail Stephens (MS, 2011)
Mineralogy and origin of copper mineralization in the Plumas copper belt, northern California.

Federico Cernuschi (MS, 2011)
Geology of the Cretaceous Lascano-East Intrusive Complex: Magmatic evolution and mineralization potential of the Merín Basin, Uruguay


(since 2010)

Tosdal, R.M., and Dilles, J.H, (accepted 10/2018, in press 12/2018) Creation of permeability in the porphyry Cu environment: Reviews in Economic Geology, Structural Geology of Mineral Deposits, ed., Rowland, J., and Rhys, D

John, D.A., Lee, R.G., Breit, G.N., Dilles, J.H., Calvert, A.T., Muffler, L.J.P., and Clynne, M.A., 2019, Pleistocene hydrothermal activity on Brokeoff Volcano and in the Maidu Volcanic Center, Lassen Peak area, northeast California: Evolution of magmatic-hydrothermal systems on stratovolcanoes: Geosphere, v. 15 (3): p. 946-982.

Hutchinson, M., and Dilles, J.H., 2019, Evidence for magmatic anhydrite in porphyry copper intrusions: Economic Geology, v. 114, no. 1, p. 143–152.

Cernuschi, F., Dilles, J. H., Grocke, S. B., Valley, J. W., Kitajima, K. and Tepley, F.J., 2018, Rapid formation of porphyry copper deposits evidenced by diffusion of oxygen and titanium in quartz: Geology, Vol.46, 611-614. doi:10.1130/G40262.1

Sepp, M. and Dilles, J.H., 2018, Structural evolution, vein orientation, and paragenesis of the Botija porphyry Cu-Mo-(Au) deposit, Colon, Panama: Economic Geology June 01, 2018, Vol.113, 857-890. doi:10.5382/econgeo.2018.4574.

Schöpa, A., Annen, C., Dilles, J., Sparks, S., and Blundy, J., 2017, Formation of the Yerington batholith – insights from thermal modeling: Economic Geology, v.112, p. 1653-1672. doi:10.5382/econgeo.2017.4525

Olson, N.H., Dilles, J.H., Kent, A.J.R., and Lang, J., 2017, Geochemistry of the Cretaceous Kaskanak Batholith and Genesis of the Pebble Porphyry Cu-Au-Mo deposit, Southwest Alaska: American Mineralogist, v. 102, p. 1597–1621.

Lee, R.G., Dilles, J.H., Tosdal, R.M., Wooden, J.L., and Mazdab, F.L., 2017, Magmatic evolution of granodiorite intrusions at the El Salvador porphyry copper deposit, Chile, based on trace element composition and U/Pb age of zircons: Economic Geology, v. 112, p. 245–273.

Johnson, C. L., Dilles, J.H., Henry, C.D., Ressel, M.W., Kent, A.J.R., and Farmer, L.P., 2015, Petrology and geochemistry of the Emigrant Pass Volcanics, Nevada: Implications for a magmatic-hydrothermal origin of the Carlin gold deposits: Geological Society of Nevada, Symposium Volume, p. 391-408.

Runyon, S.E., Barton, M.D., Dilles, J.H., Ohlin, H., Barnes, K., and Johnson, D.A., 2015, Iron oxide-rich mineralization and related alteration in the Yerington district, Lyon County, Nevada: Geological Society of Nevada, Symposium Volume 654, p. 251-285.

Somoza, R., Tomlinson, A.J., Zaffarana, C.B., Singer, S.E., Puigdomenech Negre, C.G., Raposo, M.I.B., and Dilles, J.H., 2015, Tectonic rotations and internal structure of Eocene plutons in Chuquicamata, northern Chile: Tectonophysics, v. 654, p. 113–130: aTECTO-126621

Halley, S., Dilles, J.H., & Tosdal, R.M., 2015, Footprints: Hydrothermal alteration and geo-chemical dispersion around porphyry copper deposits: SEG Newsletter, no. 100; p. 1, 12-17.

Dilles, J. H., Kent, Adam J.R, Wooden, Joseph L., Tosdal, R.M., Koleszar, Alison, Lee, Robert G., and Farmer, Lucian P., 2015, Zircon compositional evidence for sulfur-degassing from ore-forming arc magmas:  Economic Geology, v. 110, p. 241-251.

Cernuschi, F., Dilles, J.H., Kent, A.J.R., Schroer, G, Raab, A.K.,Conti, B., and Muzio, R., 2015, Geology, geochemistry and geochronology of the Cretaceous Lascano East intrusive complex and magmatic evolution of the Laguna Merín basin, Uruguay Gondwana Research, doi:10.1016/

Parsapoor, A., Khalili, M., Dilles, J.H., Mackizadeh, M. A., and Maghami, M. 2014, Stable isotope record of hydrothermal sulfate, sulfide and silicate minerals in the Darreh-Zar porphyry copper deposit in Kerman, southeastern Iran: Implications for petrogenesis and exploration:  J. Geochem. Exploration, v. 143, p. 103-115.

Maydagán, L., Franchini, M., Chiaradia, M., Dilles, J.; and Rey, R., 2014, The Altar porphyry Cu-(Au-Mo) deposit (Argentina):  a complex magmatic-hydrothermal system with evidence of recharge processes:  Economic Geology, 109(3), 621-641. doi:10.2113/econgeo.109.3.621

Chambefort, I.,  Dilles, J.H., and Longo, A.A., 2013, Amphibole geochemistry of the Yanacocha Volcanics, Peru: evidence for diverse sources of magmatic volatiles related to gold ores:   Journal of Petrology, Vol. 54, Issue 5, pp. 1017-1046.

Houston, R. A. and Dilles, J. H., 2013, Structural geologic evolution of the Butte district, Montana: Economic Geology, v. 108, no. 6, p. 1397-1424.

Walker, B.A., Klemetti, E., Grunder, A., Dilles, J., Tepley, F., Giles, D., 2013, Crystal reaming during the assembly, maturation and waning of an eleven-million-year crustal magma cycle: thermobarometry of the Aucanquilcha Volcanic cluster:  Contributions to Mineralogy & Petrology, v. 165, p. 663-682.

Hecker, Christoph, Dilles, John H., van der Meijde, Mark, and van der Meer, Freek D., 2012, Thermal infrared spectroscopy and partial least squares regression to determine mineral modes of granitoid rocks:  G cubed (Geochemistry, geophysics, geosystems), Volume 13, Number 3, (15 p.), Q03021, doi:10.1029/2011GC004004  ISSN: 1525-2027

Dilles, J.H. and Stephens, A., 2011, Age and geology of the Jurassic Lights Creek copper district, Calfornia: An Fe-oxide copper gold association: in Steininger, R., and Pennell, B., eds., Geological Society of Nevada, 2010 Symposium Volume, v. 2, p. 1007-1018.

Barton, M.D., Dilles, J.H., Girardi, J., Haxel, G., Johnson, D., Kreiner, D., Seedorff, E., and Zurcher, L., 2011, Jurassic igneous-related metallogeny of southwestern North America:  Geological Society of Nevada, 2010 Symposium Volume, v. 1, p. 373-396.

Longo, A.A.,  Dilles, J.H., Grunder, A.L., and Duncan, R., 2010, Evolution of calc-alkaline volcanism and associated hydrothermal gold deposits at Yanacocha, Perú:  Economic Geology. v. 105, p. 1191-1241 plus geology map plate.

Tomlinson, A.J., Blanco P., N., and Dilles, J.H., 2010, Carta Calama, Region de Antofagasta:  Carta Geológica de Chile, Serie Preliminar, No. 8, Subdirection Nacional de Geologia (Sernageomin), escala 1:50,000.