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.
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
Education and Certifications
2005 Ph.D., Geological & Environmental Sciences, Stanford University, Stanford CA
1998 B.A., Geology, Carleton College, Northfield MN
Honors and Awards
2012 - Presidential Early Career Award in Science and Engineering (PECASE)
Science and Products
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
Eruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada
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
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: Chapter B in
Testing fault growth models with low-temperature thermochronology in the northwest Basin and Range, USA
Chemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada
The Point Sal–Point Piedras Blancas correlation and the problem of slip on the San Gregorio–Hosgri fault, central California Coast Ranges
Evidence for large-magnitude, post-Eocene extension in the northern Shoshone Range, Nevada, and its implications for Carlin-type gold deposits in the lower plate of the Roberts Mountains allochthon
Geomorphic evidence for enhanced Pliocene-Quaternary faulting in the northwestern Basin and Range
Reappraisal of the relationship between the northern Nevada rift and Miocene extension in the northern Basin and Range Province
Superimposed extension and shortening in the southern Salinas Basin and La Panza Range, California: A guide to Neogene deformation in the Salinian block of the central California Coast Ranges
Fault geometry and cumulative offsets in the central Coast Ranges, California: Evidence for northward increasing slip along the San Gregorio-San Simeon-Hosgri fault
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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Filter Total Items: 36
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
Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and unAuthorsJoseph Colgan, David John, Christopher D. Henry, Kathryn E. WattsEruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada
The magmatic, tectonic, and topographic evolution of what is now the northern Great Basin remains controversial, notably the temporal and spatial relation between magmatism and extensional faulting. This controversy is exemplified in the northern Toiyabe Range of central Nevada, where previous geologic mapping suggested the presence of a caldera that sourced the late Eocene (34.0 mega-annum [Ma])AuthorsJoseph Colgan, Christopher D. HenryProbing 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
Late Cenozoic faulting and large-magnitude extension in the Great Basin of the western USA has created locally deep windows into the upper crust, permitting direct study of volcanic and plutonic rocks within individual calderas. The Caetano caldera in north–central Nevada, formed during the mid-Tertiary ignimbrite flare-up, offers one of the best exposed and most complete records of caldera magmatAuthorsKathryn E. Watts, David John, Joseph Colgan, Christopher D. Henry, Ilya N. Bindeman, Axel K. SchmittGeology 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: Chapter B in
SummaryThe U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A). The purpoAuthorsPeter G. Vikre, Mary Ellen Benson, Donald I. Bleiwas, Joseph Colgan, Pamela M. Cossette, Jacob DeAngelo, Connie L. Dicken, Ronald M. Drake, Edward A. du Bray, Gregory L. Fernette, Jonathan M. G. Glen, Jon E. Haacke, Susan M. Hall, Albert H. Hofstra, David John, Stephen Ludington, Mark J. Mihalasky, James J. Rytuba, Brian N. Shaffer, Lisa L. Stillings, John C. Wallis, Colin F. Williams, Douglas B. Yager, Lukas ZürcherTesting fault growth models with low-temperature thermochronology in the northwest Basin and Range, USA
Common fault growth models diverge in predicting how faults accumulate displacement and lengthen through time. A paucity of field-based data documenting the lateral component of fault growth hinders our ability to test these models and fully understand how natural fault systems evolve. Here we outline a framework for using apatite (U-Th)/He thermochronology (AHe) to quantify the along-strike growtAuthorsMagdalena A. E. Curry, Jason B. Barnes, Joseph ColganChemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada
Zircon geochronology is a critical tool for establishing geologic ages and time scales of processes in the Earth's crust. However, for zircons compromised by open system behavior, achieving robust dates can be difficult. Chemical abrasion (CA) is a routine step prior to thermal ionization mass spectrometry (TIMS) dating of zircon to remove radiation-damaged parts of grains that may have experienceAuthorsKathryn E. Watts, Matthew A. Coble, Jorge A. Vazquez, Christopher D. Henry, Joseph Colgan, David JohnByEnergy and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Groundwater and Streamflow Information Program, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science CenterThe Point Sal–Point Piedras Blancas correlation and the problem of slip on the San Gregorio–Hosgri fault, central California Coast Ranges
Existing models for large-magnitude, right-lateral slip on the San Gregorio–Hosgri fault system imply much more deformation of the onshore block in the Santa Maria basin than is supported by geologic data. This problem is resolved by a model in which dextral slip on this fault system increases gradually from 0–10 km near Point Arguello to ∼150 km at Cape San Martin, but such a model requires abandAuthorsJoseph Colgan, Richard G. StanleyEvidence for large-magnitude, post-Eocene extension in the northern Shoshone Range, Nevada, and its implications for Carlin-type gold deposits in the lower plate of the Roberts Mountains allochthon
The northern Shoshone and Toiyabe Ranges in north-central Nevada expose numerous areas of mineralized Paleozoic rock, including major Carlin-type gold deposits at Pipeline and Cortez. Paleozoic rocks in these areas were previously interpreted to have undergone negligible postmineralization extension and tilting, but here we present new data that suggest major post-Eocene extension along west-dippiAuthorsJoseph Colgan, Christopher D. Henry, David JohnByEnergy and Minerals Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science CenterGeomorphic evidence for enhanced Pliocene-Quaternary faulting in the northwestern Basin and Range
Mountains in the U.S. Basin and Range Province are similar in form, yet they have different histories of deformation and uplift. Unfortunately, chronicling fault slip with techniques like thermochronology and geodetics can still leave sizable, yet potentially important gaps at Pliocene–Quaternary (∼105–106 yr) time scales. Here, we combine existing geochronology with new geomorphic observations anAuthorsMagdalena A Ellis, Barnes Jason B, Joseph ColganByEnergy and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Groundwater and Streamflow Information Program, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science CenterReappraisal of the relationship between the northern Nevada rift and Miocene extension in the northern Basin and Range Province
The northern Nevada rift is a prominent mafic dike swarm and magnetic anomaly in north-central Nevada inferred to record the Middle Miocene (16.5-15.0 Ma) extension direction in the northern Basin and Range province in the western United States. From the 245°-250° rift direction, Basin and Range extension is inferred to have shifted 45° clockwise to a modern direction of 290°-300° during the lateAuthorsJoseph ColganSuperimposed extension and shortening in the southern Salinas Basin and La Panza Range, California: A guide to Neogene deformation in the Salinian block of the central California Coast Ranges
We synthesized data from geologic maps, wells, seismic-reflection profiles, potential-field interpretations, and low-temperature thermochronology to refine our understanding of late Cenozoic extension and shortening in the Salinian block of the central California Coast Ranges. Data from the La Panza Range and southern Salinas Basin document early to middle Miocene extension, followed by Pliocene aAuthorsJoseph Colgan, Darcy McPhee, Kristin McDougall, Jeremy K. HouriganFault geometry and cumulative offsets in the central Coast Ranges, California: Evidence for northward increasing slip along the San Gregorio-San Simeon-Hosgri fault
Estimates of the dip, depth extent, and amount of cumulative displacement along the major faults in the central California Coast Ranges are controversial. We use detailed aeromagnetic data to estimate these parameters for the San Gregorio–San Simeon–Hosgri and other faults. The recently acquired aeromagnetic data provide an areally consistent data set that crosses the onshore-offshore transition wAuthorsV. E. Langenheim, R.C. Jachens, R. W. Graymer, J.P. Colgan, C. M. Wentworth, R. G. StanleyNon-USGS Publications**
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.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.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.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.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).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.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.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.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.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.