Wes Hildreth
My eclectic and evolving USGS career began in 1977 when I was 39. I’m a field-intensive continental geologist interested in magmatism, geomorphology, tectonics, and deep-time (not real-time) geologic history. I’ve emphasized on-foot authentic geologic mapping of blank spots on the map, largely in wilderness or otherwise uninhabited areas.
My early work attracted AGU’s Bowen Award for chemical petrology (magmatic zonation of the Bishop Tuff and Novarupta 1912, isotope evolution of caldera cycles at Yellowstone, advancing the model of fundamentally basaltic transcrustal magmatism [JGR 1981]; and I was excused the wild-goose chase of Soret effects in magma chambers). IAVCEI later gave me the Thorarinsson Medal in Volcanology, recognizing numerous papers on the Katmai region, the Cascades, the Chilean Andes, my deep-crustal MASH model of arc magmatism, and the granitic Mush model of rhyolite melt extraction. GSA recently gave me (and Judy Fierstein) the 2019 Florence Bascom Geologic Mapping Award, which celebrated what I love doing best (geologic maps of Mount Adams, Mount Baker, Three Sisters, Katmai, Simcoe Mountains, Pantelleria, Quizapu–Descabezado, Mammoth Mountain, Laguna del Maule, and Long Valley caldera. Early-on, I set aside my loner tendency (imprudent in remote areas) and teamed up with Judy Fierstein, an intrepid and indefatigable field partner of 41 years. Honi soit qui mal y pense. We survived or dodged many and varied risks together. The renowned Argon Geochronology Lab at Menlo Park (directed by Brent Dalrymple, Marv Lanphere, and Andy Calvert) has been an essential support of much of our work. My career owes much to many USGS colleagues, most of all to Patrick Muffler, Bob Christiansen, Paul Bateman, and Charlie Bacon.
Professional Experience
1966-1970 Naturalist, National Park Service
1973-1975 Instructor, University of California at Berkeley
1977 Postdoc with Professor Ian Carmichael, Berkeley
1977-date Research Geologist, U.S. Geological Survey. Projects at Yellowstone; Katmai, Valley of Ten Thousand Smokes, Kaguyak caldera (AK); Pantelleria (Italy); Mammoth Mountain, Long Valley caldera, Bishop Tuff, Death Valley NP, Mojave National Preserve (CA); Mount Adams, Mount Baker, Three Sisters, Simcoe Mountains (Cascades); Descabezado-Azul-Quizapu, Tupungato, Laguna del Maule (Chile)
2006-date Senior Scientist (ST), Department of the Interior
Co-P.I. on Scientific Plan (1986) and Proposal for Research Drilling (1987) at Katmai.
International Development Bank USGS-Chile-Peru-Bolivia project on Volcanic-hosted Precious-metal Deposits in the Andes, 1990.
Co-P.I., NSF project, Chile: "Life History of an Arc Volcano,” M.A. Dungan, leader; 1991–1993.
Scientific Advisory Team, Long Valley Observatory, California Volcano Observatory, 2002–.
Education and Certifications
Harvard College, Cambridge, Massachusetts (B.A., 1961)
University of California, Berkeley (Ph.D., 1977)
Dissertation Advisors: Ian S.E. Carmichael (UC Berkeley), Charles M. Gilbert (UC Berkeley), Herbert R. Shaw (USGS)
Affiliations and Memberships*
Editorial Board, Bulletin of Volcanology, 1991-2001.
Associate Editor, JGR, 1984-86; special issue on Open Magmatic Systems.
Associate Editor, Andean Geology (formerly Revista Geológica de Chile, 1987-present
USGS Volcano Science Center, Publications review & approval designee, 1996-2013.
Geological Society of America, Fellow.
American Geophysical Union (AGU), Fellow.
AGU Fellows Selection Committee 2008–2012
International Association of Volcanology & Chemistry of Earth's Interior (IAVCEI)
IAVCEI Honors and Awards Committee 2012–2015
Honors and Awards
Detur Book Prize, Harvard College, 1958, Humanities; awarded annually since 1657.
Outstanding Soldier of the Cycle, 1959, U.S. Army.
Phi Beta Kappa, Harvard College, 1960 (Junior year election of top 8 in class of 1100).
Boston Marathon 1960, 29th place (Medals to top 35).
Sheldon Traveling Fellow, Harvard, 1961–1962 (Europe, Middle East, South Asia).
G.K. Gilbert Fellowship (U.S. Geological Survey), Chilean Andes, 1983–1985.
N.L. Bowen Award, 1985, American Geophysical Union.
Fellow of the Geological Society of America, 1985
Fellow of the American Geophysical Union, 1995.
Thorarinsson Medal, International Association of Volcanology & Chemistry of Earth's Interior: highest award in International Volcanology, 2004.
Meritorious Service Award, Department of the Interior, 2004.
Bascom Geologic Mapping Award, Geological Society of America, 2019
Abstracts and Presentations
Circum-Pacific Plutonism Project (IGCP), 1977; Invited Speaker, Japan-Korea Excursion.
Penrose Conference on Granitic Magmas, 1978; Invited Keynote Speaker.
Gordon Conference on Silicate Melt Structure, 1979; Invited Keynote Speaker.
Penrose Conference on Silicic Volcanism, 1980; Invited Keynote Speaker.
IAVCEI Conference on Arc Volcanism, Tokyo, 1981; Invited Speaker.
Tin Resources Working and Information Group; 1983.
USGS Distinguished Bradley Lecturer, 1983.
Co-Convenor of Conference on Open Magmatic Systems, Taos, New Mexico, 1984.
Workshops on Geothermal Resources of the Cascade Range, 1985; 1988; panelist, speaker.
IAVCEI Conference, New Zealand, 1986; Invited Speaker.
Hawaii Symposium on How Volcanoes Work, Hilo, 1987; Symposium Organizer.
IAVCEI—IUGG General Assembly, Vancouver, 1987; Symposium Organizer.
IAVCEI General Assembly, Santa Fe, 1989; Program Committee.
IAVCEI Commission on Explosive Volcanism: Valley of Ten Thousand Smokes (Alaska) field-trip leader; 10 days on foot, 1991.
GSA Annual Meeting, Seattle, 1994, Opening Keynote Speaker on Cascade Magmatism.
Penrose Conference on Silicic Magmatism, Mammoth Lakes, CA, 2001; Opening Keynote Speaker, “Critical overview of silicic magmatism.”
Scientific Committee, IAVCEI General Assembly (Chile, 2004), 2002-04. Convener of Symposium on Arc Magmatism. Thorarinsson Lecturer.
GSA Cordilleran Section Meeting, 2010, Field trip leader, Long Valley and Mammoth Mountain.
Devils Postpile National Monument, Centennial Celebration, 2011, Field trip leader.
National Park Service Centennial Speaker 2016, at Devils Postpile National Monument.
IAVCEI General Assembly, Portland, OR, 2017, Invited Keynote Speaker on Geologic Mapping. Field-trip leader to Long Valley caldera and the Bishop Tuff.
Science and Products
The plinian eruptions of 1912 at Novarupta, Katmai National Park, Alaska
Modelling the petrogenesis of high Rb/Sr silicic magmas
Isotopic and chemical evidence concerning the genesis and contamination of basaltic and rhyolitic magma beneath the Yellowstone Plateau Volcanic Field
Reply to Comment on "Crustal contributions to arc magmatism in the Andes of Central Chile" by W. Hildreth and S. Moorbath
Geophysics at Katmai: Geophysical expedition to Novarupta Volcano, Katmai National Park, Alaska
Crustal contributions to arc magmatism in the Andes of Central Chile
The hydrothermal system of the Calabozos caldera, central Chilean Andes
New perspectives on the eruption of 1912 in the valley of ten thousand smokes, Katmai National Park, Alaska
Partition coefficients determined from phenocryst and glass analyses of the climactic ejecta of Mount Mazama, Oregon
Geology of the peralkaline volcano at Pantelleria, Strait of Sicily
Correlation of ash-flow tuffs
A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California
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
- Publications
Filter Total Items: 65
The plinian eruptions of 1912 at Novarupta, Katmai National Park, Alaska
The three-day eruption at Novarupta in 1912 consisted of three discrete episodes. Episode I began with plinian dispersal of rhyolitic fallout (Layer A) and contemporaneous emplacement of rhyolitic ignimbrites and associated proximal veneers. The plinian column was sustained throughout most of the interval of ash flow generation, in spite of progressive increases in the proportions of dacitic and aAuthorsJ. Fierstein, W. HildrethModelling the petrogenesis of high Rb/Sr silicic magmas
Rhyolites can be highly evolved with Sr contents as low as 0.1 ppm and Rb Sr > 2,000. In contrast, granite batholiths are commonly comprised of rocks with Rb Sr < 10 and only rarely > 100. Mass-balance modelling of source compositions, differentiation and contamination using the trace-element geochemistry of granites are therefore commonly in error because of the failure to account for evolved difAuthorsA. N. Halliday, J.P. Davidson, W. Hildreth, P. HoldenIsotopic and chemical evidence concerning the genesis and contamination of basaltic and rhyolitic magma beneath the Yellowstone Plateau Volcanic Field
Since 2.2 Ma, the Yellowstone Plateau Volcanic Field has produced ~6000 km3 of rhyolite tuffs and lavas in >60 separate eruptions, as well as ~100 km3 of tholeiitic basalt from >50 vents peripheral to the silicic focus. Intermediate eruptive products are absent. Early postcollapse rhyolites show large shifts in Nd, Sr, Pb, and O isotopic composition caused by assimilation of roof rocks and hydrothAuthorsW. Hildreth, A. N. Halliday, R. L. ChristiansenReply to Comment on "Crustal contributions to arc magmatism in the Andes of Central Chile" by W. Hildreth and S. Moorbath
[No abstract available]AuthorsW. Hildreth, S. MoorbathGeophysics at Katmai: Geophysical expedition to Novarupta Volcano, Katmai National Park, Alaska
The great eruption of 1912 in the Aleutian Range of Alaska (Figure 1) is exceptional for both its size and relative simplicity. It was the largest eruption of this century and the largest rhyolitic outburst in almost 20 centuries. The 60-hour, 30-km3 (ejecta volume) eruption produced extensive fallout deposits, an ash-flow sheet that gave rise to the Valley of Ten Thousand Smokes, and the 3-km-diaAuthorsJohn C. Eichelberger, S. Ballard, Charles R. Carrigan, A. Goodliffe, W. Hildreth, E.Y. Iwatsubo, P. W. Kasameyer, T. E. C. Keith, Juergen Kienle, J. J. Papike, D. D. Pollard, D.B. Stone, P. C. Wallmann, P.L. Ward, M. Wilt, M. E. YountCrustal contributions to arc magmatism in the Andes of Central Chile
Fifteen andesite-dacite stratovolcanoes on the volcanic front of a single segment of the Andean arc show along-arc changes in isotopic and elemental ratios that demonstrate large crustal contributions to magma genesis. All 15 centers lie 90 km above the Benioff zone and 280??20 km from the trench axis. Rate and geometry of subduction and composition and age of subducted sediments and seafloor areAuthorsW. Hildreth, S. MoorbathThe hydrothermal system of the Calabozos caldera, central Chilean Andes
Active thermal springs associated with the late Pleistocene Calabozos caldera complex occur in two groups: the Colorado group which issues along structures related to caldera collapse and resurgence, and the Puesto Calabozos group, a nearby cluster that is chemically distinct and probably unrelated to the Colorado springs. Most of the Colorado group can be related to a hypothetical parent water coAuthorsA.L. Grunder, J. M. Thompson, W. HildrethNew perspectives on the eruption of 1912 in the valley of ten thousand smokes, Katmai National Park, Alaska
New data extend our understanding of the 1912 eruption, its backfilled vent complex at Novarupta, and magma-storage systems beneath adjacent stratovolcanoes. Initial Plinian rhyolite fallout is confined to a narrow downwind sector, and its maximum thickness may occur as far as 13 km from source. In contrast, the partly contemporaneous rhyolite-rich ash flows underwent relatively low-energy emplaceAuthorsW. HildrethPartition coefficients determined from phenocryst and glass analyses of the climactic ejecta of Mount Mazama, Oregon
No abstract available.AuthorsC. R. Bacon, Wes Hildreth, T. H. DruittGeology of the peralkaline volcano at Pantelleria, Strait of Sicily
Situated in a submerged continental rift, Pantelleria is a volcanic island with a subaerial eruptive history longer than 300 Ka. Its eruptive behavior, edifice morphologies, and complex, multiunit geologic history are representative of strongly peralkaline centers. It is dominated by the 6-km-wide Cinque Denti caldera, which formed ca. 45 Ka ago during eruption of the Green Tuff, a strongly rheomoAuthorsG.A. Mahood, W. HildrethCorrelation of ash-flow tuffs
Discrimination and correlation of ash-flow sheets is important in structurally complex, long-lived volcanic fields where such sheets provide the best keys to the regional stratigraphic framework. Three-dimensional complexities resulting from pulsatory eruptions, sectorial emplacement, mechanical sorting during outflow, thermal and compositional zoning of magmas, the physical zoning of cooling unitAuthorsW. Hildreth, G. MahoodA Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California
The Bishop Tuff represents a single eruption of chemically zoned rhyolitic magma. Six whole rock samples spanning the compositional and temperature range yield initial87Sr/86Sr of 0.7060–0.7092 andδ18O of 5.9–10.3‰. Six constituent sanidines yield smaller ranges of initial87Sr/86Sr of 0.7061–0.7069 andδ18O of 6.7–7.9. In contrast143Nd/144Nd ratios for the six whole rocks and two constituent magnetAuthorsA. N. Halliday, A.E. Fallick, J. Hutchinson, W. HildrethNon-USGS Publications**
Hildreth, W., 1976, Death Valley Geology: Death Valley Natural History Association, Furnace Creek, CA, 64 p.
Ewart, A., Hildreth, W., and Carmichael, I.S. E., 1975, Quaternary acid magma in New Zealand: Contributions to Mineralogy and Petrology, v. 51, p. 1–27.
**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.
- Data
- Maps
- Multimedia
- News
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government