Andrew Todd Calvert, PhD

As Scientist-in-Charge of the California Volcano Observatory (CalVO), I lead the ~35 geologists, geophysicists and hydrologists that study and monitor volcanoes in California and other domestic and international volcanoes.  CalVO also maintains laboratories to study many aspects of volcanic behavior.  CalVO is located in Menlo Park and Moffett Field on the San Francisco Peninsula.

Biography

Education

Ph.D., University of California – Santa Barbara                     

Dissertation: Metamorphism and exhumation of mid-crustal gneiss domes in the Arctic Alaska Terrane

 

M.S./B.S., Stanford University (both degrees conferred June 1992)

Thesis: Structural Evolution and Thermochronology of the Kigluaik Mountains, Seward Peninsula, Alaska

 

Research Accomplishments

My research focuses on using and improving K/Ar and 40Ar/39Ar geochronology techniques to develop eruptive histories for active volcanoes.  Through geologic mapping, geochemical characterization, and high precision geochronology we can characterize a volcano’s prior behavior.  These eruptive histories along with geochemistry and geophysics form the basic data for volcanic hazard assessments, and long-term hazard assessments provide the context for hazard assessment during volcanic crises. 

Eruptive history of Cascade and Aleutian Arc Volcanoes, an example from the Three Sisters

Most mapped volcanoes appear to be built episodically and characterizing these episodes offers insight into future eruptive behavior.  Middle Sister is the most chemically diverse and youngest of the Three Sisters Volcanic Cluster (Hildreth et al., 2012).  Dated, mapped lava flows precede and postdate the remarkably productive (fourfold increase in output between 50 – 15 thousand years) and silicic rhyolite episode best exposed at South Sister.  Our Middle Sister paper (Calvert et al., 2018) chronicles mafic, intermediate and silicic eruptions from peripheral and central vents and compares timing and compositions with the largely-silicic products of South Sister (Fierstein et al., 2011).   

Growth of Hawaiian volcanoes

Despite being some of the best-studied volcanoes on earth, little was known about the inception ages and lifespans of Hawaiian volcanoes, largely because early-erupted samples are inaccessible and all samples are difficult to date accurately and precisely. The chemical progression from alkalic to tholeiitic and back to alkalic compositions is well-characterized, yet the timescales of this variation have been difficult to constrain. Even volume estimates vary significantly because a new edifice may develop on the flank of an older shield.  A collaborative agreement between USGS and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) provided submersible access to early-erupted materials and a unique opportunity to constrain inception ages and compositional evolution rates of the most productive volcanic center on earth. 

We undertook to date submarine samples from the south flank of Kilauea, Mahukona and Hilo Ridge to develop a basic framework for the time-volume development of Hawaiian volcanoes. Lavas from an intact section of weakly alkalic basalts on submarine flank of Kilauea and strongly alkalic blocks from debris flows beneath Kilauea are indistinguishable at 147±14 ka and older strongly alkalic samples range from 212±38 ka to 280±20 ka (Calvert and Lanphere, 2006).  This finding shows that Kilauea is a relatively young volcano and the voluminous younger, tholeiitic lavas were erupted at higher rates than generally assumed.  This work refutes previous studies dating the tholeiitic lavas at 500 ka along the active rift zone and in drill core. Weakly-alkalic rocks from Hilo Ridge yielded 1150±20 ka ages, far too old to belong to their assumed source, Mauna Kea.  Hilo Ridge instead belongs to Kohala volcano, which is now estimated to have erupted from 1,200 to 280 ka (Lipman and Calvert, 2011).  Mauna Kea had been reported to be more voluminous than other centers on Hawaii, however, this result requires that the submarine Hilo Ridge belongs to Kohala, not Mauna Kea, reducing the estimated eruptive volume of Mauna Kea by nearly 50% (42 to 22 km3) and increasing the volume of Kohala (64 km3) nearly to that of Mauna Loa (83 km3).

Lipman and Calvert (2013) compiled all geochronologic constraints and reinterpreted the growth history for the island of Hawaii. This work has a large impact on the inception age, erupted volume and lifespan of individual Hawaiian volcanoes and has significant petrologic implications.  Previous attempts to date early portions of active Hawaiian volcanoes had significant uncertainty and our work yields a more reliable framework. Tying Hilo Ridge to Kohala overturns the long-standing interpretation of the basic geology of Hawaii Island that Mauna Kea was the largest volcano on Hawaii, and offers an explanation for complicated textures, chemistry and isotopes in the Hawaiian Scientific Drill Hole.

Publications

Christiansen, R.L., Calvert, A.T., Champion, D.E., Gardner, C.A., Fierstein, J.E. and Vazquez, J.A., in review, The remarkable volcanism of Shastina, a stratocone segment of Mount Shasta, California, Geosphere.

Stelten, M.E., Downs, D.T., Champion, D.E., Dietterich, H.R., Calvert, A.T., Sisson, T.W., Mahood, G.A., Zahran, H., 2019, The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia, Geological Society of America Bulletin, https://doi.org/10.1130/B35337.1

Fleck, R.J., Calvert, A.T., Coble, M.A., Wooden, J.L., Hodges, K., Hayden, L.A., van Soest, M.C., du Bray, E. and John, D.A., 2019, Characterization of the Rhyolite of Bodie Hills and 40Ar/39Ar Intercalibration with Ar Mineral Standards, Chemical Geology, v. 525, p. 282-302.

Sisson, T.W., Schmitt, A.K., Danisik, M., Calvert, A.T,, Pempena, N., Huang, C. and Shen, C., 2019, Age of the dacite of Sunset Amphitheater, a voluminous Pleistocene tephra from Mount Rainier (USA), and implications for Cascade glacial stratigraphy, Journal of Volcanology and Geothermal Research, v. 376, p. 27-43.

John, D.A., Lee, R.G., Breit, G.N., Dilles, J.H., Calvert, A.T., Muffler, L.J.P. and Clynne, M.A., 2019, Pleistocene hydrothermal activity on Brokeoff volcano and in the Maidu volcanic center, Lassen Peak area, northeast California: Evolution of magmatic-hydrothermal systems on stratovolcanoes, Geosphere, v. 15, no. 3, p. 946-982.

DeLano, K, Lee, J., Roper, R. and Calvert, A.T., 2019, Dextral, normal, and sinistral faulting across the eastern California shear zone–Mina deflection transition, California-Nevada, USA Geosphere, https://doi.org/10.1130/GES01636.1

Germa, A., Perry, C., Quidelleur, X., Calvert, A., Clynne, M., Connor, C.B., Connor, L.J., Malservisi, R. and Charbonnier, S., 2019, Temporal relationship between the Lassen volcanic center and mafic regional volcanism, Bulletin of Volcanology, 81: 38, https://doi.org/10.1007/s00445-019-1296-7

Kortemeier, W., Calvert, A., Moore, J.G. and Schweickert, R., 2018, Pleistocene volcanism and shifting shorelines at Lake Tahoe, California, Geosphere, v. 14, no. 2, p. 812-834.

Calvert, A.T., Fierstein, J. and Hildreth, W., 2018, Eruptive history of Middle Sister, Oregon Cascades, USA–Product of a late Pleistocene eruptive episode, Geosphere, v. 14, no. 5, p. 2118-2139.

Hildreth, W., Fierstein, J. and Calvert, A.T., 2018, McGee Till—oldest glacial deposit in the Sierra Nevada, California— and Quaternary evolution of the rangefront escarpment, Quaternary Science Reviews, v. 198, p. 242-265.

Hildreth, W., Calvert, A.T., Fierstein, J. and Marcaida, M., 2018, Volcanic eruptions in the Mammoth Lakes Sierra—Past and Future, USGS Fact Sheet 2018-3059.

Hildreth, W., Fierstein, J. and Calvert, A., 2017, Early postcaldera rhyolite and structural resurgence at Long Valley Caldera, California, Journal of Volcanology and Geothermal Research, v. 335, p. 1-34.

Wright, H.M., Vazquez, J.A., Champion, D.E., Calvert, A.T., Mangan, M.T., Stelten, M., Cooper, K.M., Herzig, C., Schriener, A., 2015, Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating, Geochemistry, Geophysics, Geosystems, v. 16, no. 4, p. 1198-1210.

Stelten, M.E., Cooper, K.M., Vazquez, J.A., Calvert, A.T. and Glessner, J.J.G., 2015, Mechanisms and timescales of generating eruptible rhyolitic magmas at Yellowstone caldera from zircon and sanidine geochronology and geochemistry, Journal of Petrology, Volume 56, Issue 8, August 2015, Pages 1607-1642.

Matthews, N.E., Vazquez, J.A. and Calvert, A.T., 2015, Age of the Lava Creek super-eruption and magma chamber assembly from combined 40Ar/39Ar and U-Pb dating of sanidine and zircon crystals, Geochemistry, Geophysics, Geosystems, https://doi.org/10.1002/2015GC005881.

Downs, D.T., Rowland, J.V., Wilson, C.J.N., Rosenberg, M.D., Calvert, A.T., Leonard, G.S. and Keall, J.M., 2014, Age and eruptive center of the Paeroa Subgroup ignimbrites (Whakamaru Group) within the Taupo Volcanic Zone of New Zealand, Geological Society of America Bulletin, v. 126, no. 9-10, p. 1131-1144.

Downs, D.T., Wilson, C.J.N., Cole, J.W., Rowland, J.V., Leonard, G.S. and Calvert, A.T., 2014, Evolution of the intra-arc Taupo-Reporoa Basin within the Taupo Volcanic Zone of New Zealand, Geosphere, v. 10, no. 1, p. 185-206.

Fleck, R.J., Hagstrum, J.T., Calvert, A.T., Evarts, R.C. and Conrey, R.M., 2014, 40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA, Geosphere, v. 10, no. 6, p. 1283-1314.

Hildreth, W., Fierstein, J., Champion, D. and Calvert, A., 2014, Mammoth Mountain and its mafic periphery—A late Quaternary volcanic field in eastern California, Geosphere, v. 10, no. 6, p. 1315-1365.

Field, L., Blundy, J., Calvert, A. and Yirgu, G., 2013, Magmatic history of Dabbahu, a composite volcano in the Afar Rift, Ethiopia, Geological Society of America Bulletin, v. 125, no. 1-2 p. 128-147.

Scarpati, C., Perrotta, A., Lepore, S., Calvert, A., 2013, Eruptive history of Neapolitan volcanoes: constraints from 40Ar–39Ar dating, Geological Magazine, v. 150, no. 3, p. 412-425, doi:10.1017/ S0016756812000854.

Medynski, S., Pik, R., Burnard, P., Williams, A., Vye-Brown, C., Ferguson, D., Blard, P.-H., France, L., Yirgu, G., Seid, J.I., Ayalew, D. and Calvert, A., 2013, Controls on magmatic cycles and development of rift topography of the Manda Hararo segment (Afar, Ethiopia): Insights from cosmogenic 3He investigation of landscape evolution Earth and Planetary Science Letters, v. 367, p. 133-145.

Lipman, P.W. and Calvert, A.T., 2013, Modeling volcano growth on the Island of Hawaii: Deep-water perspectives, Geosphere, v. 9, no. 5, p. 1348-1383.

Nagorsen-Rinke, S., Lee, J., Calvert, A., 2013, Pliocene sinistral slip across the Adobe Hills, eastern California–western Nevada: Kinematics of fault slip transfer across the Mina deflection Geosphere, v. 9, no. 1, p. 37-53.

Ferguson, D.J., Calvert, A.T., Pyle, D.M., Blundy, J.D., Yirgu, G., Wright, T., 2013, Constraining timescales of focused magmatic accretion and extension in the Afar crust using lava geochronology, Nature Communications, v. 4, article 1416.

Jicha, B.R., Coombs, M. L., Calvert, A.T., and Singer, B.S., 2012, Geology and 40Ar/39Ar geochronology of the medium- to high-K Tanaga volcanic cluster, western Aleutians, Geological Society of America Bulletin, v. 124, no. 5-6, p. 842-856.

Hildreth, W., Fierstein, J. and Calvert, A., 2012, Geologic Map of the Three Sisters volcanic cluster, Cascade Range, Oregon, U.S. Geological Survey Scientific Investigations Map 3186, scale 1:24,000, 2 sheets, pamphlet 107 p.

Shaanan, U., Porat, N., Navon, O., Weinberger, R., Calvert, A., and Weinstein, Y., 2011, OSL dating of a Pleistocene maar: Birket Ram, the Golan Heights, Journal of Volcanology and Geophysical Research, v. 201, no. 1-4, p. 397-403.

Muffler, L.J.P., Clynne, M.A., Calvert, A.T. and Champion, D.E., 2011, Diverse, discrete, mantle-derived magma batches erupted along a short normal fault zone:  the Poison Lake chain, southernmost Cascades, Geological Society of America Bulletin, v. 123, no. 11-12, p. 2177-2200.

Lipman, P. W. and Calvert, A.T., 2011, Early growth of Kohala Volcano and formation of long Hawaiian rift zones, Geology, v. 39, no. 7, p. 659-662.

Fedele, L., Insinga D.D., Calvert A.T., Morra V., Perrotta A., and Scarpati C., 2011, 40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity, Bulletin of Volcanology, v. 73, no. 9, p. 1323-1336.

Fierstein, J., Hildreth, W., and Calvert, A.T., 2011, Eruptive History of South Sister, Oregon Cascades, Journal of Volcanology and Geothermal Research, v. 207, no. 3-4, p. 145-179.

Coble, M.A., Grove, M. and Calvert, A.T., 2011, Calibration of Nu-Instruments Noblesse multicollector mass spectrometers for argon isotopic measurements using a newly developed reference gas, Chemical Geology, v. 290, no. 1-2, p. 75-87.

Hanyu, T., Kimura, J., Katakuse, M., Calvert, A.T., Sisson, T.W., and Nakai, S., 2010, Source materials for inception stage Hawaiian magmas: Pb‐He isotope variations for early Kilauea, Geochemistry, Geophysics, Geosystems, v. 11, Q0AC01, 25p.

Mangan, M., Miller, T., Waythomas, C., Trusdell, F., Calvert, A., and Layer, P., 2009, Diverse lavas from closely spaced volcanoes drawing from a common parent: Emmons Lake Volcanic Center, Eastern Aleutian Arc, Earth and Planetary Science Letters v. 287, no. 3-4, p. 363-372

Cassel, E.J., Calvert, A.T., and Graham, S.A., 2009, Age, geochemical composition, and distribution of Oligocene ignimbrites in the northern Sierra Nevada, California: Implications for landscape morphology, elevation, and drainage divide geography of the Nevadaplano, International Geology Review v. 51, no. 7-8, p. 723-742.

Clague, D.A., and Calvert, A.T, 2009, Postshield stage transitional volcanism on Mahukona Volcano, Hawaii, Bulletin of Volcanology v. 71, no. 5, p. 533-539.

Mortimer, N., Hauff, F., and Calvert, A.T., 2008, Continuation of the New England Orogen, Australia, beneath the Queensland Plateau and Lord Howe rise, Australian Journal of Earth Sciences v. 55, no. 2, p. 195-209.

Clynne, M.A., Calvert, A.T., Wolfe, E.W., Evarts, R.C., Fleck, R.J., and Lanphere, M.A., 2008, The Pleistocene eruptive history of Mount St. Helens, Washington, from 300,000 to 12,800 years before present, in, Sherrod, D.R., Scott, W.E., and Stauffer, P.H., eds., A volcano rekindled; the renewed eruption of Mount St. Helens, 2004-2006: U.S. Geological Survey Professional Paper 1750, p. 593-627.

Lanphere, M., Champion, D., Melluso, L., Morra, V., Perrotta, A., Scarpati, C., Tedesco, D., and Calvert, A., 2007, 40Ar/39Ar ages of the AD 79 eruption of Vesuvius, Italy, Bulletin of Volcanology, v. 69, p. 259-263.

Mortimer,  N., Herzer , R.H., Gans, P.B., Laporte-Magoni,  C.,  Calvert, A.T., and Bosch, D., 2007, Oligocene–Miocene tectonic evolution of the South Fiji Basin and Northland Plateau, SW Pacific Ocean: Evidence from petrology and dating of dredged rocks, Marine Geology, v. 237, p. 1-24.

Wilson, C.J.N., Rhoades, D.A., Lanphere, M.A., Calvert, A.T., Houghton, B.F., Weaver, S.D., and Cole, J.W., 2007, A multiple-approach radiometric age estimate for the Rotoiti and Earthquake Flat eruptions, New Zealand, with implications for the MIS 4/3 boundary, Quaternary Science Reviews 26 (13-14), pp. 1861-1870.

Hildreth, W,, Fierstein, J., and Calvert, A,T., 2007, Blue Mountain and The Gas Rocks: Rear-Arc Dome Clusters on the Alaska Peninsula; Studies by the U.S. Geological Survey in Alaska, 2006, Professional Paper 1739-A, 17p.

Hartz, E.H., Kristiansen, S.N., Calvert, A., Hodges, K.V. and Heeremans, M., 2006, Structural, thermal and rheological control of the late Paleozoic basins in East Greenland, Proceedings of the Fourth International Conference on Arctic Margins, OCS Study, Minerals Management Service, 2006-003, p. 58 – 76.

Calvert, A.T., Moore, R.B., McGeehin, J.P., and Rodrigues da Silva, A.M., 2006,  Volcanic history and 40Ar/39Ar and 14C geochronology of Terceira Island, Azores, Portugal, Journal of Volcanology and Geothermal Research, v. 156, no. 1-2, p. 103-115.

Calvert, A.T. and Lanphere, M.A., 2006, Argon geochronology of Kilauea’s early submarine history, in Coombs, M. L., Eakins, B. W., and Cervelli, P. F., eds., Growth and Collapse of Hawaiian Volcanoes: Journal of Volcanology and Geothermal Research, v. 151, p. 1-18.

Lipman, P.W., Sisson, T.W., Coombs, M.L., Calvert, A., and Kimura, J., 2006, Piggyback tectonics: Long-term growth of Kilauea on the south flank of Mauna Loa, in Coombs, M. L., Eakins, B. W., and Cervelli, P. F., eds., Growth and Collapse of Hawaiian Volcanoes: Journal of Volcanology and Geothermal Research, v. 151, p. 73-108.

Insinga, D., Calvert, A., Lanphere, M., Morra, V., Perrotta, A., Sacchi, M., Scarpati, C., Saburomaru, J., and Fedele, L., 2006, The Late-Holocene evolution of Miseno area (western sector of Campi Flegrei, southern Italy) as inferred by stratigraphy, petrochemistry and 40Ar/39Ar geochronology, in De Vivo, B., ed., Volcanism in the Campania Plain: Vesuvius, Campi Flegrei and Ignimbrites, Elsevier, Developments in Volcanology, p. 97 – 124.

Calvert, A. T., Moore, R. B., and McGimsey, R. G., 2005, Argon geochronology of late Pleistocene to Holocene Westdahl Volcano, Unimak Island, Alaska: U.S. Geological Survey Professional Paper 1709-D, p. 1-16 [available at http://pubs.usgs.gov/pp/pp1709d].

Tauxe, L., Luskin, C., Selkin, P., Gans, P., Calvert, A., 2004, Paleomagnetic results from the Snake River Plain: Contribution to the time-averaged field global database, Geochemistry, Geophysics, GeosystemsCalvert, A.T. and Mortimer, N., 2003, Thermal History of Transantarctic Mountains K-feldspars, Southern Victoria Land, Terra Antarctica, v. 10, no. 1, p. 3-15.

Mortimer, N., Herzer, R.H., Walker, N.W., Calvert, A.T., Seward, D., and Chaproniere, G.C.H., 2003, Cavalli Seamount, Northland Plateau, SW Pacific Ocean; a Miocene metamorphic core complex?, Journal of the Geological Society of London, v. 160, no. 6, p. 971-983.

Ratschbacher, L., Hacker, B.R., Calvert, A., Webb, L.E., Grimmer, J.C., McWilliams, M.O., Ireland, T., Dong, S., and Hu, J., 2003, Tectonics of the Qinling (Central China): Tectonostratigraphy, geochronology, and deformation history, Tectonophysics v. 366, no. 1-2, p. 1-53.

Hacker, B.R., Calvert, A., Zhang, R.Y., Ernst, W.G., and Liou, J.G., 2003, Ultrarapid exhumation of ultrahigh-pressure diamond-bearing metasedimentary rocks of the Kokchetav Massif, Kazakhstan?, Lithos v. 70, no. 3-4, p. 61-75.

Amato, J.M., Miller, E.L., Calvert, A.T., Toro, J., Wright, J.E., 2003, Potassic magmatism on St. Lawrence Island, Alaska, and Cape Dezhnev, Northeast Russia: Evidence for early Cretaceous subduction in the Bering Strait region, 2003, Short Notes on Alaska Geology 2001, p. 1-20.

Vogl, J.J., Calvert, A.T., and Gans, P.B., 2002, Mechanisms and timing of exhumation of collision-related metamorphic rocks, southern Brooks Range, Alaska: Insights from 40Ar/39Ar thermochronology, Tectonics, v. 21. no. 3, p. 2-1 to 2-17.

Akinin, V.V. and Calvert, A.T., 2002, Cretaceous mid-crustal metamorphism and exhumation of the Koolen gneiss dome, Chukotka Peninsula, northeastern Russia, in Miller, E.L., Grantz, S.L. and Klemperer, S.L., eds., Tectonic Evolution of the Bering Shelf-Chukchi Sea-Arctic Margin and Adjacent Landmasses: Boulder, Colorado, Geological Society of America Special Paper 360, p. 147-165.

De Vivo, B. Rolandi, G., Gans, P.B., Calvert, A., Bohrson, W.A., Spera, F.J., and Belkin, H.E., 2001, New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy), Mineralogy and Petrology, v. 73, p. 47-65.

El-Shazly, A.K., Brocker, M., Hacker, B., and Calvert, A., 2001, Formation and Exhumation of Blueschists and Eclogites from NE Oman: New Constraints from Rb-Sr and 40Ar/39Ar dating, Journal of Metamorphic Geology, v. 19, no. 3, p. 233-248.

Lee, J., Rubin, C.M., and Calvert, A., 2001, Quaternary faulting history along the Deep Springs Fault, California, Geological Society of America Bulletin, v. 113, no. 7, p. 855-869.

Blisniuk, P.M., Hacker, B.R., Glodny, J., Ratschbacker, L., Bi Siwen, Wu Zhenhan, McWilliams, M.O., and Calvert, A., 2001, Normal faulting in central Tibet since at least 13.5 Myr ago, Nature, v. 412, no. 6847, p. 628-632.

Brown, E.H., Talbot, J.L., McClelland, W.C., Feltman, J.A., Lapen, T.J., Bennett, J.D., Hettinga, M.A., Troost, M.L., Alvarez, K.M., and Calvert, A.T., 2000, Interplay of plutonism and regional deformation in an obliquely convergent arc, southern Coast Belt, British Columbia, Tectonics, v. 19, no. 3, p. 493-511.

Hacker, B.R., Ratschbacher, L., Webb, L.E., McWilliams, M., Ireland, T., Calvert, A., Dong, S., Wenk, H.-R., and Chateigner, D., 2000, Exhumation of ultrahigh-pressure rocks in east central China; Late Triassic-Early Jurassic tectonic unroofing. Journal of Geophysical Research, B, v. 105, no. 6, p. 13,339 - 13,364.

Lee, J., Hacker, B.R., Dinklage, W.S., Wang, Y, Gans, P., Calvert, A., Wan J., Chen, W., Blythe, A., and McClelland, W., 2000, Evolution of the Kangmar Dome, southern Tibet: Structural, petrologic, and thermochronologic constraints, Tectonics, v. 19, no. 5, p. 872-895.

Ratschbacher, L., Hacker, B.R., Webb, L.E., McWilliams, M.O., Ireland, T.R., Dong, S., Calvert, A., Chateigner, D., and Wenk, H.-R., 2000, Exhumation of the ultrahigh-pressure continental crust in east-central China: Cretaceous and Cenozoic unroofing and the Tan-Lu Fault. Journal of Geophysical Research, B, v. 105, no. 6, p. 13,301 - 13,338.

Calvert, A. T., 1999, Metamorphism and exhumation of mid-crustal gneiss domes in the Arctic Alaska Terrane, [Ph.D. Thesis] University of California, Santa Barbara, 213 p.

Calvert, A.T., Gans, P.B., and Amato, J.M., 1999, Diapiric ascent and cooling of a sillimanite gneiss dome revealed by 40Ar/39Ar thermochronology: the Kigluaik Mountains, Seward Peninsula, Alaska, in Ring, U., Brandon, M.T., Lister, G., and Willett, S. [eds], Geological Society of London Special Volume on Exhumation Processes: Normal Faulting, Ductile Flow, and Erosion, v. 154, p. 205-232.

Mortimer, N., Gans, P., Calvert, A., and Walker, N., 1999, Geology and thermochronology of the east edge of the Median Batholith (Median Tectonic Zone): a new perspective on Permian to Jurassic crustal growth of New Zealand, The Island Arc, v. 8, no. 3, p. 404-425.

Bering Strait Geologic Field Party (Akinin, V.V., Gelman, M.L., Sedov, B.M., Amato, J.M.; Miller, E.L., Toro, J., Calvert, A.T., Fantini, R.M., Wright, J.E., Natal’in, B.A.), 1997, Koolen metamorphic complex, NE Russia; implications for the tectonic evolution of the Bering Strait region, Tectonics, v. 16, no. 5, p. 713-729.

Dumitru, Trevor A., Miller, E. L., O’Sullivan, P. B., Amato, J. M., Hannula, K.A., Calvert, A.T., and Gans, P. B., 1995, Cretaceous to Recent extension in the Bering Strait region, Alaska, Tectonics, v. 14, no. 3, p. 549-563.

Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska, Geology, v. 20, no. 6, p. 487-490.

Calvert, A. T., 1992, Structural Evolution and Thermochronology of the Kigluaik Mountains, Seward Peninsula, Alaska, [M.S. Thesis] Stanford University, 86 p.