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
Oligocene and Miocene arc volcanism in northeastern California: evidence for post-Eocene segmentation of the subducting Farallon plate
Hydrothermal alteration of the Late Eocene Caetano ash-flow caldera, north-central Nevada: A field and ASTER remote sensing study
Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada
Provenance and palaeogeographic implications of Eocene-Oligocene sedimentary rocks in the northwestern Basin and Range
Rapid middle Miocene collapse of the Mesozoic orogenic plateau in north-central Nevada
Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff
Large-magnitude Miocene extension of the Eocene Caetano caldera, Shoshone and Toiyabe Ranges, Nevada
Tectonic and magmatic evolution of the northwestern Basin and Range and its transition to unextended volcanic plateaus: Black Rock Range, Nevada
Two-phase Neogene extension in the northwestern basin and range recorded in a single thermochronology sample
Miocene extension in the East Range, Nevada: A two-stage history of normal faulting in the northern basin and range
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.
Science and Products
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Filter Total Items: 34
Oligocene and Miocene arc volcanism in northeastern California: evidence for post-Eocene segmentation of the subducting Farallon plate
The Warner Range in northeastern California exposes a section of Tertiary rocks over 3 km thick, offering a unique opportunity to study the long-term history of Cascade arc volcanism in an area otherwise covered by younger volcanic rocks. The oldest locally sourced volcanic rocks in the Warner Range are Oligocene (28–24 Ma) and include a sequence of basalt and basaltic andesite lava flows overlainAuthorsJ.P. Colgan, A.E. Egger, D. A. John, B. Cousens, R. J. Fleck, C.D. HenryHydrothermal alteration of the Late Eocene Caetano ash-flow caldera, north-central Nevada: A field and ASTER remote sensing study
Geologic mapping and analysis of ASTER remote sensing data were used to define the effects of a large hydrothermal system in the 12–18 by 22 km Caetano caldera. The caldera formed at ~33.8Ma during eruption of >1100km3 of the rhyolitic Caetano Tuff that left a 1 km deep basin which was partly filled by a lake. Magma resurgence resulted in shallow(<1 km) emplacement of the Redrock Canyon granite poAuthorsDavid John, Barnaby W. Rockwell, Christopher D. Henry, Joseph ColganRapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada
Paleozoic rocks in the northern Ruby Mountains were metamorphosed during Mesozoic crustal shortening and Cenozoic magmatism, but equivalent strata in the southern Ruby Mountains were never buried deeper than stratigraphic depths prior to exhumation in the footwall of a west dipping brittle normal fault. In the southern Ruby Mountains, Miocene sedimentary rocks in the hanging wall of this fault datAuthorsJoseph Colgan, Keith A. Howard, Robert J. Fleck, Joseph L. WoodenProvenance and palaeogeographic implications of Eocene-Oligocene sedimentary rocks in the northwestern Basin and Range
A thick sequence of uppermost Eocene to lower Oligocene volcaniclastic and sedimentary rocks is exposed at the base of the Warner Range in northeastern California. This isolated exposure provides insight into the palaeogeographic setting of the northwestern Basin and Range during this time period. Significant thinning of the unit over 35km of lateral exposure and predominantly volcanic clast compoAuthorsA.E. Egger, J.P. Colgan, C. YorkRapid middle Miocene collapse of the Mesozoic orogenic plateau in north-central Nevada
The modern Sierra Nevada and Great Basin were likely the site of a high-elevation orogenic plateau well into Cenozoic time, supported by crust thickened during Mesozoic shortening. Although crustal thickening at this scale can lead to extension, the relationship between Mesozoic shortening and subsequent formation of the Basin and Range is difficult to unravel because it is unclear which of the maAuthorsJoseph Colgan, Christopher D. HenryMagmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff
The Caetano Tuff is a late Eocene, rhyolite ash-flow tuff that crops out within an ∼90-km-long, east-west–trending belt in north-central Nevada, previously interpreted as an elongate graben or “volcano-tectonic trough.” New field, petrographic, geochemical, and geochronologic data show that: (1) the east half of the “trough” is actually the Caetano caldera, formed by eruption of the Caetano Tuff aAuthorsDavid John, Christopher D. Henry, Joseph ColganLarge-magnitude Miocene extension of the Eocene Caetano caldera, Shoshone and Toiyabe Ranges, Nevada
Because major mineral deposits in north-central Nevada predate significant Basin and Range extension, a detailed understanding of the timing and kinematics of extensional faulting is necessary to place these deposits in their original structural context. The complexity of pre-Cenozoic deformation in northern Nevada makes restoring Basin and Range faulting difficult without locating well-dated, regAuthorsJoseph Colgan, David John, Christopher D. Henry, Robert J. FleckTectonic and magmatic evolution of the northwestern Basin and Range and its transition to unextended volcanic plateaus: Black Rock Range, Nevada
The seismically active eastern and western margins of the northern Basin and Range have been extensively studied, yet the northwestern margin of the province remains incompletely understood. The Black Rock Range of northwestern Nevada straddles the transition from the Basin and Range province to the south and east, and flat-lying volcanic plateaus to the west. This poorly understood range preserveAuthorsD.W. Lerch, E. Miller, M. McWilliams, J. ColganTwo-phase Neogene extension in the northwestern basin and range recorded in a single thermochronology sample
We use a combination of apatite 4He/3He, (U-Th)/ He, and fission-track thermochronology to date slip on the Surprise Valley fault in northeastern California by analyzing a single sample from the Warner Range in the footwall of the fault. This sample, a granitic clast from a conglomerate, yielded a fission-track age of 11.6 ?? 2.8 Ma and a (U-Th)/He age of 3.02 ?? 0.52 Ma. Geologic relationships inAuthorsJ.P. Colgan, D.L. Shuster, P.W. ReinersMiocene extension in the East Range, Nevada: A two-stage history of normal faulting in the northern basin and range
The East Range in northwestern Nevada is a large, east-tilted crustal block bounded by west-dipping normal faults. Detailed mapping of Tertiary stratigraphic units demonstrates a two-phase history of faulting and extension. The oldest sedimentary and volcanic rocks in the area record cumulative tilting of -30??-45??E, whereas younger olivine basalt flows indicate only a 15??-20??E tilt since ca. 1AuthorsJ.C. Fosdick, J.P. ColganNon-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.