A specific research objective of mine is to better understand submarine eruption, magma fragmentation and dispersal processes. To do this my research team combines field studies of modern and ancient deposits exposed on the seafloor and on land with laboratory based analytical approaches.

Associate Editor for the Journal of Sedimentary Research

My teaching background includes courses in mineralogy, petrology, sedimentology/stratigraphy, volcanology, geologic field-mapping and marine geology.

Paduan, J.B., Clague, D.A., Caress, D.W., Portner, R.A., Le Saout, M., Dreyer, B.M. (2026).Voluminous inflated lobate flows on the distal rift zones of Axial Seamount, Juan de Fuca Spreading Ridge, Geochemistry, Geophysics, Geosystems; https://doi.org/10.1029/2025GC012675

Portner, R.A., Xu, G.; Murch, A.P., Clague, D.A., Dreyer, B.M., Paduan, J.B. (2025). Mid-ocean ridge (MOR) ash dispersal on Axial Seamount, Juan de Fuca Ridge, Geochemistry, Geophysics, Geosystems; https://doi.org/10.1029/2025GC012229

Stubseid, H.H., Bjerga, A., Portner, R.A., Haflidason, H., Pedersen, R.B., (2025). Construction of ultraslow-spreading oceanic crust: Volcanic processes and deposits at the Mohns Ridge, Geochemistry, Geophysics, Geosystems, https://doi.org/10.1029/2024GC012141

Ede, R., Portner, R.A., (2023). Geologic Map of the Depoe Bay and Newport North USGS Quadrangles, Oregon. EdMap Technical Report G21AC10457-00, 29 p., 1:24,000.

Portner, R.A., Dreyer, B.M., Clague, D.A., Daczko, N.R., Castillo, P.R., Spelz-Madero, R., (2022). Oceanic Zircon records rhyolite formation on the Alarcon Rise mid-ocean ridge. Journal of Petrology, v. 63, no. 6, https://doi.org/10.1093/petrology/egac040 (Editors choice).

Murch, A.P., Portner, R.A., Rubin, K.H., Clague D.A., (2022). Deep-subaqueous implosive volcanism at West Mata Seamount, Tonga. Earth and Planetary Science Letters, v. 578, https://doi.org/10.1016/j.epsl.2021.117328.

Portner, R.A., Dreyer, B.M., Clague, D.A., (2021). Mid-ocean-ridge rhyolite (MORR) eruptions on the East Pacific Rise lack the fizz to pop. Geology, v. 49, no. 4, p. 377-381, https://doi.org/10.1130/G47820.1.

Clague, D.A., Caress, D.W., Dreyer, B.M., Lundsten, L., Paduan, J.B., Portner, R.A., Spelz-Madero, R., Bowles, J.A., Castillo, P.R., Guardado-France, R., Le Saout, M., Martin, J.F., Santa Rosa-del Río, M.A., and Zierenberg, R.A., (2018). Geology of the Alarcon Rise, Southern Gulf of California. Geochemistry, Geophysics, Geosystems, https://doi.org/10.1002/2017GC007348

Clague, D.A., Paduan, J.B., Caress, D.W., Chadwick, W.W., Le Saout, M., Dreyer, B.M., and Portner, R.A. (2017). High-resolution AUV mapping and targeted ROV observations of three historic lava flows at Axial Seamount. Oceanography, v. 30, no. 4, https://doi.org/10.5670/oceanog.2017.426.

Portner, R.A., Clague D.A., Helo C., Dreyer, B. D., Paduan, J.B. (2015). Contrasting styles of deep-marine explosive eruptions revealed from Axial Seamount push core records. Earth and Planetary Science Letters, v.423, p. 219-231, https://doi.org/10.1016/j.epsl.2015.03.043.

Clague, D.A., Dreyer, B.M., Paduan, J.B., Martin, J.F., Caress, D.W., Gill, J.B., Kelley, D.S., Thomas, H., Portner, R.A., Delaney, J.R., Guilderson, T.P., and McGann, M.L. (2014). Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages. Geochemistry Geophysics Geosystems, v. 15, no. 8, pg. 3364-3391, https://doi.org/10.1002/2014GC005415.

Portner, R.A., Clague, D.A., Paduan, J.B. (2014). Caldera formation and varied eruption styles on North Pacific seamounts: the clastic lithofacies record. Bulletin of Volcanology, v. 76, no. 845, 28p., https://doi.org/10.1007/s00445-014-0845-3

Clague, D.A., Dreyer, B.M., Paduan, J.B., Caress, D.W., Chadwick Jr., W.W., Embley, R.W., Thomas, H. Portner, R.A., Guilderson, T.P., McGann, M.L., Butterfield, D.A. (2013). Geologic History of the summit of Axial seamount, Juan de Fuca Ridge. Geochemistry Geophysics Geosystems, v. 14, no. 10; p. 4403-4443, doi.org/10.1002/ggge.20240

Portner, R.A., Dickinson, J.A., Daczko, N.R. (2011). Interaction of gravity flows with a rugged mid-ocean ridge seafloor: an outcrop example from Macquarie Island. Journal of Sedimentary Research, v. 81, p. 355-375, https://doi.org/10.2110/jsr.2011.30.

Portner, R.A., Murphy, M.J., Daczko, N.R, (2011). A detrital record of lower oceanic crust exhumation within a Miocene slow-spreading ridge: Macquarie Island, Southern Ocean. Geological Society of America Bulletin, v. 123, p. 255-273, https://doi.org/10.1130/B30082.1.

Portner, R.A., Daczko, N.R., Murphy, M.J., Pearson, N.J. (2011). Enriching mantle melts within a dying mid-ocean spreading ridge: insights from Hf-isotope and trace element patterns in detrital oceanic zircon. Lithos, v. 126, p. 355-368, https://doi.org/10.1016/j.lithos.2011.07.017

Portner, R.A., Hendrix, M.S., Stalker, J.C., Miggins, D., Sheriff, S.D. (2011). Sedimentary response to orogenic exhumation in the northern Rocky Mountain Basin and Range province, Flint Creek Basin, west-central Montana. Canadian Journal of Earth Sciences, v. 48, p. 1131-1153, https://doi.org/10.1139/e10-107

Portner, R.A., Daczko, N.R., Dickinson, J.A. (2010). Vitriclastic lithofacies from Macquarie Island (Southern Ocean): compositional influence on abyssal eruption explosivity in a dying Miocene spreading ridge. Bulletin of Volcanology, v. 72, p. 165-183, https://doi.org/10.1007/s00445-009-0312-8

Daczko, N.R., Harb, N., Portner, R.A., Dickinson, J.A. (2009). Geochemical fingerprint of hyaloclasts in glassy fragmental rocks of Macquarie Island. Australian Journal of Earth Sciences, v. 56, p. 951-963, https://doi.org/10.1080/08120090903005402

Dickinson, J.A., Harb. N., Portner, R.A., Daczko, N.R. (2009). Glassy fragmental rocks of Macquarie Island (Southern Ocean): Mechanism of formation and deposition. Sedimentary Geology, v. 216, p. 91-103, https://doi.org/10.1016/j.sedgeo.2009.02.001

Portner, R.A Hendrix, M.S. (2005). Preliminary Geologic Map of the Eastern Flint Creek Basin, West Central Montana. Montana Bureau of Mines and Geology, Open File Report 521, 17 p., 1:24,000.

Active:

Arctic and North Atlantic Mid-Ocean Ridge system (Gakkel, Lena Trough, Mohns)

Hunga Tonga-Hunga Ha'apai Volcano- Tongan Arc, Southwest Pacific Ocean

Coast Range Ophiolite, Northern California, USA

Axial Seamount - Juan de Fuca Ridge, North Pacific Ocean

Alarcon Rise - Northern East Pacific Rise, Central Pacific Ocean

Inactive:

West Mata Volcano - Lau Basin, Southwest Pacific Ocean

Columbia Rive Flood basalt, Central Oregon, USA

Macquarie Island Ophiolite, Tasamania, Australia, Southern Ocean

Northern Basin and Range Province, Western Montana, USA

Appalachian Foreland Basin, Southern West Virginia, USA