Research

Our science occupies the crossroads of geochemistry, petrology, structural geology, and tectonics. We investigate fluid movement in the deep earth, rock thermal histories, chemical signatures of rock deformation, and rates of geologic processes.

Our main research tools are field work, petrography, and in situ microanalysis, including electron microprobe, electron-backscatter diffraction, Raman spectroscopy, and secondary ion mass spectrometry.

Fractured and zoned garnet from the Picuris Mountains, New Mexico

Mesoproterozoic tectonics of the Picuris Orogen

Investigating the P-T-t-D paths recorded by Mesoproterozoic sedimentary and volcanic rocks of the ca. 1.4 Ga Picuris orogeny in the southern Picuris Mountains (New Mexico) type locale

Bonamici, C.E., Sulthaus, D.S., Evidence for transpression in the Picuris Orogen: the deformation record of the Marqueñas Formation metaconglomerate, Picuris Mountains, New Mexico, USA, on-line at Geosphere, https://doi.org/10.1130/GES02805.1

Supported by NSF EAR 2241801

Schists and pegmatites of the Grand Canyon, looking down 91-Mile Canyon toward the Colorado River.

Grand Canyon Basement

Refining the ca. 1.7 Ga metamorphic and orogenic history of rocks of the Inner Gorge of the Grand Canyon

Autrey-Mulligan S., Bonamici C.E., Williams, M.L, 2025, Applications of quartz-in-garnet elastic geobarometry to mid-crustal Barrovian metamorphic rocks demonstrated using tensionally stressed inclusions from the Grand Canyon: Journal of Metamorphic Geology, v. 43, p. 734-753, https://doi.org/10.1111/jmg.70002

Autrey-Mulligan, S.M., Bonamici, C.E., Williams, M.L., Karlstrom, K.E., Condit, C.B., 2024, Resolving pressure differences within the Grand Canyon Precambrian basement: Implications for Proterozoic tectonics: Geology, v. 52, no. 4, p. 266-270. https://doi.org/10.1130/G51706.1

Bonamici, C.E., and Duebendorfer, E.M., 2009, Gravitational collapse of a Paleoproterozoic orogen, southern Hualapai Mountains, Arizona: Precambrian Research, v. 175, p. 35-50. https://doi.org/10.1016/j.precamres.2009.08.003

Studying extreme fluid-driven metamorphism of the Big Maria Mountains, CA. Image courtesy of Khalil Droubi.

Laramide Fluids & Metasomatism

Investigating the source of ore-forming, Laramide-age fluids with in situ geochemical tools

Supported by NSF EAR 2318412

EBSD map of ice crystals in graupel (small hailstone). Color indicates crystallographic orientation. Image courtesy of Noah Brown.

Ice Microstructure

Using cryogenic SEM and Raman to map the crystal structure of ice from Antarctic glaciers, hailstones, deformation experiments, and synthetic Solar System proxies

Supported by UW2020 grant from the Wisconsin Alumni Research Foundation

Deformed ca. 1.05 Ga titanite from the Adirondack Mountains, New York.

Shear experiment to study the deformation behavior of titanite. Image courtesy of Amy Moser.

Titanite Microstructure, Geochemistry & Geochronology

Leveraging the power of the mineral titanite to date metamorphism, fluid infiltration, and deformation

Droubi, O.K., Bauer, A.M., Bonamici, C.E., Nachlas, W.O., Garber, J., Tappa, M., Reimink, J., 2025, Eoarchean-Paleoproterozoic tectonothermal history of the Acasta Gneiss Complex constrained by titanite and apatite petrochronology, v. 26, e2025GC012294, https://doi.org/10.1029/2025GC012294

Droubi, O.K., Bauer, A.M., Bonamici, C.E., Tappa, M.J., Nachlas, W.O., Garber, J.M., Reimink, J.R., 2023, U-Th-Pb and trace element evaluation of existing titanite and apatite LA-ICP-MS reference materials and determination of 208Pb/232Th-206Pb/238U date discordance in Archean accessory phases: Geostandards and Geoanalytical Research, v. 47, 2337-369. https://doi.org/10.1111/ggr.12488

Bonamici, C.E., Blum, T.B., 2020, Reconsidering initial Pb in titanite in the context of in situ dating: American Mineralogist, v. 105, p. 1672-1685. https://doi.org/10.2138/am-2020-7274

Bonamici, C.E., Fanning, C.M., Kozdon, R., Fournelle, J.H., and Valley, J.W., 2015, Combined oxygen-isotope and U-Pb zoning studies of titanite: New criteria for age preservation: Chemical Geology, v. 398, p. 70-84. https://doi.org/10.1016/j.chemgeo.2015.02.002

Bonamici, C.E., Kozdon, R., Ushikubo, T., and Valley, J.W., 2014. Intragrain oxygen isotope zoning in titanite by SIMS: cooling rates and fluid infiltration along the Carthage-Colton Mylonite Zone, Adirondack Mountains, NY, USA: Journal of Metamorphic Geology: v. 32, p. 71-92. https://doi.org/10.1111/jmg.12059

Bonamici, C.E., Kozdon, R., Ushikubo, T., and Valley, J.W., 2011, High-resolution P-T-t paths from δ18O zoning in titanite: A snapshot of late-orogenic collapse in the Grenville of New York: Geology, v.10, p. 959-962, https://doi.org/10.1130/G32130.1

Oxygen isotope zoning in feldspars from the footwall of the Buckskin low-angle detachment fault. Figure courtesy of Guillaume Siron.

Thermal & Fluid Histories from Oxygen Isotopes

Using intragrain oxygen isotope zoning in minerals to reconstruct rock histories

Roig González, C.I., Bonamici, C.E., Blum, T.B., Nachlas, W.O., 2024, Footwall refrigeration versus footwall hydration: Reassessing steep thermal gradients below detachment faults with in situ SIMS oxygen isotope quartz-epidote analysis: Earth & Planetary Science Letters, v. 646, 118962, doi: 10.1016/j.epsl.2024.118962.

Kropf, G., Bonamici, C.E., Borchers, B., 2021, Updating the Fast Grain Boundary program: Temperature-time paths from intragrain oxygen isotope zoning: Computers & Geosciences, v. 151, 104753. https://doi.org/10.1016/j.cageo.2021.104753

Supported by NSF EAR 1650355

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