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
Magma storage prior to the 1912 eruption at Novarupta, Alaska
Bacon receives 1999 Bowen Award
Mount Mageik: A compound stratovolcano in Katmai National Park: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
Katmai volcanic cluster and the great eruption of 1912
The Puelche volcanic field: Extensive Pleistocene rhyolite lava flows in the Andes of central Chile
The age and constitution of Cerro Campanario, a mafic stratovolcano in the Andes of central Chile
Hybrid fall deposits in the Bishop Tuff, California: A novel pyroclastic depositional mechanism
Complexities of plinian fall deposition at vent: An example from the 1912 Novarupta eruption (Alaska)
Primitive magmas at five Cascade volcanic fields: Melts from hot, heterogeneous sub-arc mantle
The Bishop Tuff: New insights from eruptive stratigraphy
Kulshan caldera: A quaternary subglacial caldera in the North Cascades, Washington
Potassium-argon geochronology of a basalt-andesite-dacite arc system: the Mount Adams volcanic field, Cascade Range of southern Washington
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
Magma storage prior to the 1912 eruption at Novarupta, Alaska
New analytical and experimental data constrain the storage and equilibration conditions of the magmas erupted in 1912 from Novarupta in the 20th century's largest volcanic event. Phase relations at H2O+CO2 fluid saturation were determined for an andesite (58.7 wt% SiO2) and a dacite (67.7 wt%) from the compositional extremes of intermediate magmas erupted. The phase assemblages, matrix melt composAuthorsJ.E. Hammer, M.J. Rutherford, W. HildrethBacon receives 1999 Bowen Award
Charles R. Bacon received the 1999 Bowen Award, presented by the Volcanology Geochemistry, and Petrology Section during the 1999 AGU Fall Meeting.AuthorsWes Hildreth, Charles R. BaconMount Mageik: A compound stratovolcano in Katmai National Park: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
Mount Mageik is an ice-clad 2,165-m andesite-dacite stratovolcano in the Katmai volcanic cluster at the head of the Valley of Ten Thousand Smokes. New K-Ar ages indicate that the volcano is as old as 93±8 ka. It has a present-day volume of 20 km3 but an eruptive volume of about 30 km3, implying a longterm average volumetric eruption rate of about 0.33 km3 per 1,000 years. Mount Mageik consists ofAuthorsWes Hildreth, Judy Fierstein, Marvin A. Lanphere, David F. SiemsKatmai volcanic cluster and the great eruption of 1912
In June 1912, the world's largest twentieth century eruption broke out through flat-lying sedimentary rocks of Jurassic age near the base of Trident volcano on the Alaska Peninsula. The 60 h ash-flow and Plinian eruptive sequence excavated and subsequently backfilled with ejecta a flaring funnel-shaped vent since called Novarupta. The vent is adjacent to a cluster of late Quaternary stratocones anAuthorsW. Hildreth, J. FiersteinThe Puelche volcanic field: Extensive Pleistocene rhyolite lava flows in the Andes of central Chile
A remote volcanic field in the rugged headwaters of the Rio Puelche and Rio Invernada (35.8??S) constitutes the largest cluster of Quaternary rhyolite lava flows yet identified in the Andean Southern Volcanic Zone. The Puelche Volcanic Field belongs to an intra-arc belt of silicic magmatic centers that extends, at least, 140 km north-south and lies well east of the volcanic front but nonetheless cAuthorsW. Hildreth, J. Fierstein, E. Godoy, Robert E. Drake, B. SingerThe age and constitution of Cerro Campanario, a mafic stratovolcano in the Andes of central Chile
Cerro Campanario, a towering landmark on the continental divide near Paso Pehuenche, is a glacially eroded remnant of a mafic stratovolcano that is much younger than previously supposed. Consisting of fairly uniform basaltic andesite, rich in olivine and plagioclase, the 10-15 km3 edifice grew rapidly near the end of the middle Pleistocene, about 150-160 ka, as indicated by 40Ar/39Ar and unspikedAuthorsW. Hildreth, B. Singer, E. Godoy, F. MunizagaHybrid fall deposits in the Bishop Tuff, California: A novel pyroclastic depositional mechanism
Hybrid fall deposits in the Bishop Tuff show features common to both archetypal fall and surge deposits. Like normal-fall deposits, they have an overall plane-parallel bedding and flat-lying pumice clasts but also, like surge deposits, they show variable development of cross-bedding, some crystal and pumice sorting, and some rounding of pumice clasts. All variations exist from normal-fall depositsAuthorsC. J. N. Wilson, W. HildrethComplexities of plinian fall deposition at vent: An example from the 1912 Novarupta eruption (Alaska)
An extremely proximal ejecta ring, with exposures to within 100 m of vent, was deposited during later-stage plinian fall activity during the 1912 Novarupta eruption in Alaska. One bed in the ejecta ring (bed S) contains predominantly andesitic clasts which serve to delineate the striking contrast in thinning rates along dispersal axis of the ejecta ring [Pyle bt values of 70 m (bed S alone) or 190AuthorsJ. Fierstein, Bruce F. Houghton, C. J. N. Wilson, W. HildrethPrimitive magmas at five Cascade volcanic fields: Melts from hot, heterogeneous sub-arc mantle
Major and trace element concentrations, including REE by isotope dilution, and Sr, Nd, Pb, and O isotope ratios have been determined for 38 mafic lavas from the Mount Adams, Crater Lake, Mount Shasta, Medicine Lake, and Lassen volcanic fields, in the Cascade arc, northwestern part of the United States. Many of the samples have a high Mg# [100Mg/(Mg + FeT) > 60] and Ni content (>140 ppm) such thatAuthorsC. R. Bacon, P. E. Bruggman, R. L. Christiansen, M.A. Clynne, J. M. Donnelly-Nolan, W. HildrethThe Bishop Tuff: New insights from eruptive stratigraphy
The 0.76 Ma Bishop Tuff, from Long Valley caldera in eastern California, consists of a widespread fall deposit and voluminous partly welded ignimbrite. The fall deposit (F), exposed over an easterly sector below and adjacent to the ignimbrite, is divided into nine units (F1‐F9), with no significant time breaks, except possibly between F8 and F9. Maximum clast sizes are compared with other depositsAuthorsC. J. N. Wilson, W. HildrethKulshan caldera: A quaternary subglacial caldera in the North Cascades, Washington
Calderas that collapse during large pyroclastic eruptions are anomalously rare in the Cascade arc. Recognition of the early Pleistocene 4.5 × 8 km Kulshan caldera, filled with rhyodacite ignimbrite at the northeast foot of Mount Baker, brings to only three the Quaternary calderas identified in the Cascades. A near-vertical ring fault cut in basement rocks of the North Cascades encloses 30 km2 of iAuthorsW. HildrethPotassium-argon geochronology of a basalt-andesite-dacite arc system: the Mount Adams volcanic field, Cascade Range of southern Washington
High-precision K-Ar dating and detailed mapping have established an eruptive chronology for a Cascade stratovolcano and its surrounding array of coeval basaltic centers. The time-volume-composition data bear upon several fundamental questions concerning the long-term behavior of arc volcanoes. -from AuthorsAuthorsW. Hildreth, M. A. LanphereNon-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.
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*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