Joseph Colgan

I study magmatism and deformation of the earth’s crust, and how these processes influence the formation and distribution of natural resources and geologic hazards. This work involves geologic mapping at different scales, interpretation of subsurface and geophysical data, and laboratory analyses to determine the age and composition of rocks and minerals.




2005      Ph.D., Geological & Environmental Sciences, Stanford University, Stanford CA

1998      B.A., Geology, Carleton College, Northfield MN


Professional Experience

2014 - present     Research Geologist, USGS, Denver CO

2009 - 2014         Research Geologist, USGS, Menlo Park CA

2006 - 2009         Mendenhall Postdoctoral Fellow, USGS, Menlo Park CA

1999 - 2005         Teaching and Research Assistant, Stanford University, Stanford CA

1998 - 1999         Earth Science Intern, USGS, Menlo Park CA



Watts, K.E., John, D.A., Colgan, J.P., Henry, C.D., Bindeman, I.N., and Valley, J.W., 2019, An oxygen isotopic investigation of silicic magmatism in the Stillwater caldera complex, Nevada: Generation of large-volume low-d18O rhyolitic tuffs and assessment of their regional context in the Great Basin of the western United States: Geological Society of America Bulletin. [link]

Johnstone, S.A., and Colgan, J.P., 2018, Interpretation of low-temperature thermochronometer ages from tilted normal fault blocks: Tectonics, v. 37, 21 p., [link]

Colgan, J.P., John, D.A., Henry, C.D., and Watts, K.E., 2018, Insights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater – Clan Alpine caldera complex, western Nevada, USA: Journal of Volcanology and Geothermal Research, v. 349, p. 163–176, doi:10.1016/j.jvolgeores.2017.10.015. [link]

Colgan, J.P., and Henry, C.D., 2017, Eruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada: U.S. Geological Survey Professional Paper 1832, 44 p. [link]

Curry, M.A.E., Barnes, J.B., and Colgan, J.P., 2016, Testing fault growth models with low-temperature thermochronology in the northwest Basin and Range, USA: Tectonics, v. 35, doi:10.1002/2016TC004211. [link]

Watts, K.E., John, D.A., Colgan, J.P., Henry, C.D., Bindeman, I.N., and Schmitt, A.K., 2016, Probing the volcanic–plutonic connection and the genesis of crystal-rich rhyolite in a deeply dissected supervolcano in the Nevada Great Basin: Source of the late Eocene Caetano Tuff: Journal of Petrology, v. 57(8), p. 1599–1644, doi: 10.1093/petrology/egw051. [link]

Vikre, P.G., Benson, M.E., Bleiwas, D.I., Colgan, J.P., Cossette, P.M., DeAngelo, J., Dicken, C.L., Drake, R.M., II, du Bray, E.A., Fernette, G.L., Glen, J.M.G., Haacke, J.E., Hall, S.M., Hofstra, A.H., John, D.A., Ludington, S., Mihalasky, M.J., Rytuba, J.J., Shaffer, B.N., Stillings, L.L., Wallis, J.C., Williams, C.F., Yager, D.B., and Zürcher, L., 2016, Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: U.S. Geological Survey Scientific Investigations Report 2016–5089–B, 220 p. [link]

Watts, K.E., Coble, M.A., Vazquez, J.A., Henry, C.D., Colgan, J.P., and John, D.A., 2016, Chemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada: Chemical Geology, v. 439, p. 139–151, doi:10.1016/j.chemgeo.2016.06.013. [link]

Colgan, J.P., and Stanley, R.G., 2016, The Point Sal–Point Piedras Blancas correlation and the problem of slip on the San Gregorio–Hosgri fault, central California Coast Ranges: Geosphere, v. 12(3), p. 971–984, doi:10.1130/GES01289.1. [link]

Ellis (Curry), M.A., Barnes, J.B., and Colgan, J.P., 2015, Geomorphic evidence for enhanced Plio-Quaternary faulting in the northwestern Basin and Range?: Lithosphere, 14 p., doi:10.1130/L401.1. [link]

Colgan, J.P., Henry, C.D., and John, D.A., 2014, Evidence for large-magnitude, post-Eocene extension in the northern Shoshone Range, Nevada, and its implications for the structural setting of Carlin-type gold deposits in the lower plate of the Roberts Mountains allochthon: Economic Geology, v. 109, p. 1843–1862. [link]

Henry, C.D., Bell, J.W., John, D.A., and Colgan, J.P., 2013, Preliminary geologic map of the West Gate quadrangle, Churchill County, Nevada: Nevada Bureau of Mines and Geology Open-File Report 13-9, scale 1:24,000. [link]

Colgan, J.P., 2013, Reappraisal of the relationship between the northern Nevada rift and Miocene extension in the northern Basin and Range Province: Geology, v. 41(2), p. 211-214, doi: 10.1130/G33512.1. [link]

Langenheim, V.E., Jachens, R.C., Graymer, R.W., Colgan, J.P., Wentworth, C.M., and Stanley, R.G., 2013, Fault geometry and cumulative offsets in the central Coast Ranges, California: Evidence for northward increasing slip on the San Gregorio-San Simeon-Hosgri Fault: Lithosphere, v. 5(1), p. 29-48, doi:10.1130/L233.1. [link]

Colgan, J.P., McPhee, D.K., McDougall, K., and Hourigan, J.K., 2012, Superimposed extension and shortening in the southern Salinas Basin and La Panza Range, California: A guide to Neogene deformation of the Salinian block in the central California Coast Ranges: Lithosphere, v. 4(5) p. 411–429, doi:10.1130/L208.1. [link]

Henry, C.D., Hinz, N.H., Faulds, J.E., Colgan, J.P., John, D.A., Brooks, E.R., Cassel, E.J., Garside, L.J., Davis, D.A., and Castor, S.B., 2012, Eocene–Early Miocene paleotopography of the Sierra Nevada–Great Basin–Nevadaplano based on widespread ash-flow tuffs and paleovalleys: Geosphere, v. 8, p. 1–27, doi:10.1130/GES00727.1. [link]

Colgan, J.P. Henry, Christopher D., and John, D.A., 2011, Geologic map of the Caetano caldera, Lander and Eureka Counties, Nevada: Nevada Bureau of Mines and Geology Map 174, Scale 1:75,000. [link]

Colgan, J.P., Egger, A.E., John, D.A., Cousens, B., Fleck, R.J., and Henry, C.D., 2011, Oligocene and Miocene arc volcanism in northeastern California: Evidence for post-Eocene segmentation of the subducting Farallon plate: Geosphere, v. 7, p. 733–755, doi:10.1130/GES00650.1. [link]

Henry, C.D., McGrew, A.J., Colgan, J.P., Snoke, A.W., and Brueseke, M.E., 2011, Timing, distribution, amount, and style of Cenozoic extension in the northern Great Basin, in Lee, J., and Evans, J.P., eds., Geologic Field Trips to the Basin and Range, Rocky Mountains, Snake River Plain, and Terranes of the U.S. Cordillera: Geological Society of America Field Guide 21, p. 27–66, doi:10.1130/2011.0021(02). [link]

John, D.A., Rockwell, B.W., Henry, C.D., and Colgan, J.P., 2011, Hydrothermal alteration of the late Eocene Caetano ash-flow caldera, north-central Nevada: A field and ASTER remote sensing study: Proceedings of the Geological Society of Nevada 2010 Symposium, Reno, Nevada, May 14–22, 2010, p. 1055–1083.

Henry, C.D., and Colgan, J.P., 2011, The regional structural setting of the 2008 Wells earthquake and Town Creek Flat basin—Implications for the Wells earthquake fault and adjacent structures, in dePolo C.M., and LaPointe, D.D., eds., A compendium of earthquake-related investigations prepared by the University of Nevada, Reno: Nevada Bureau of Mines and Geology Special Publication 36, p. 53–64. [link]

Colgan, J.P., Howard, K.A., Fleck R.J., and Wooden J.L., 2010, Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada: Tectonics, v. 29, doi:10.1029/2009TC002655. [link]

Colgan, J.P., Wyld, S.J., and Wright, J., 2010, Geologic map of the Vicksburg Canyon 7.5’ quadrangle, Humboldt County, Nevada: Nevada Bureau of Mines and Geology Map M169, scale 1:24,000. [link]

Egger, A.E., Colgan, J.P., and York, C., 2009, Provenance and palaeogeographic implications of Eocene–Oligocene sedimentary rocks in the northwestern Basin and Range: International Geology Review, v. 51(9-11), p. 900–911, doi: 10.1080/00206810902949829. [link]

Colgan, J.P., and Henry, C.D., 2009, Rapid middle Miocene collapse of the Mesozoic orogenic plateau in north-central Nevada: International Geology Review, v. 51(9-11), p. 920–961, doi: 10.1080/00206810903056731. [link]

Lerch, D.W., Klemperer, S.L., Egger, A.E., Colgan, J.P., and Miller, E.L., 2009, The northwestern margin of the Basin and Range Province, part 1:  Reflection profiling of the moderate-angle (35°) Surprise Valley Fault: Tectonophysics, v. 488(1–4), p. 143–149, doi:10.1016/j.tecto.2009.05.028. [link]

Fosdick, J.C, and Colgan, J.P., 2008, Miocene extension in the East Range, Nevada: A two-stage history of normal faulting in the northern Basin and Range: Geological Society of America Bulletin, v. 120(9-10), p. 1198–1213. doi:10.1130/B26201.1. [link]

Colgan, J.P., Shuster, D.L., and Reiners, P.W., 2008, Two-phase Neogene extension of the northwestern Basin and Range recorded in a single thermochronology sample: Geology, v. 36(8), p. 631–634, doi:10.1130/G24897A.1. [link]

Colgan, J.P., John, D.A., Henry, C.D., and Fleck, R.J., 2008, Large-magnitude Miocene extension of the Eocene Caetano caldera, Shoshone and Toiyabe Ranges, Nevada: Geosphere, v. 4(1), p. 107–130. doi:10.1130/GES00115.1. [link]

John, D.A., Henry, C.D., and Colgan, J.P., 2008, Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted mid-Tertiary eruptive center and source of the Caetano Tuff: Geosphere, v. 4(1), p. 75–106. doi:10.1130/GES00116.1. [link]

Lerch, D.W., Miller, E.L., McWilliams, M.O., and Colgan, J.P., 2008, Tectonic and magmatic evolution of the northwestern Basin and Range and its transition to unextended volcanic plateaus: Black Rock Range, Nevada: Geological Society of America Bulletin, v. 120 (3-4), p. 300–311. doi:10.1130/B26151.1. [link]

Mattinson, C.G., Colgan, J.P., Metcalf, J.R., Miller E.L., and Wooden, J.L., 2007, Late Cretaceous to Paleocene metamorphism and magmatism in the Funeral Mountains metamorphic core complex, Death Valley, California, in Cloos, M., Carlson, W.D., Gilbert, M.C., Liou, J.G., and Sorensen, S.S., eds., Convergent Margin Terranes and Associated Regions: A Tribute to W.G. Ernst: Geological Society of America Special Paper 419, p. 205–223, doi:10.1130/2006.2419(11). [link]

Lerch, D.W., Klemperer, S.L., Glen, J.M.G., Ponce, D.A., Miller, E.L., and Colgan, J.P., 2007, Crustal structure of the northwestern Basin and Range Province and its transition to unextended volcanic plateaus: Geochemistry, Geophysics, and Geosystems, v. 8, doi:10.1029/2006GC001429. [link]

Colgan, J.P., Dumitru, T.A., Reiners, P.W., Wooden, J.L., and Miller, E.L., 2006, Cenozoic tectonic evolution of the Basin and Range Province in northwestern Nevada: American Journal of Science, v. 306(8), p. 616–654. [link]

Colgan, J.P., Dumitru, T.A., McWilliams, M.O., and Miller, E.L., 2006, Timing of Cenozoic volcanism and Basin and Range extension in northwestern Nevada: new constraints from the northern Pine Forest Range: Geological Society of America Bulletin, v. 118(1-2), p. 126–139, doi:10.1130/B25681.1. [link]

Colgan, J.P., 2005, Timing and magnitude of Basin and Range extension in northwestern Nevada, Stanford, Calif., Stanford University, Ph.D. Thesis, 172 p.

Colgan, J.P., Dumitru, T.A., and Miller, E.L., 2004, Diachroneity of Basin and Range faulting and Yellowstone hotpsot volcanism in northwestern Nevada: Geology, v. 32(2), p. 121–124, doi:10.1130/G20037.1. [link]

Brabb, E.E., Colgan, J.P., and Best, T.C., 2000 Map showing inventory and regional susceptibility for Holocene debris flows and related fast-moving landslides in the conterminous United States: U.S. Geological Survey Miscellaneous Field Studies Map MF-2329, scale 1:2,500,000. [link]