Ryan Portner


Photo of Ryan Portner

Assistant Professor: Sedimentology

Phone: 408 924-5009
Office: DH 202
Office Hours (Fall 2020): By Appointment via Zoom / Google Chat
E-mail: ryan.portner@sjsu.edu

Dr. Portner's website



  • Ph.D. 2010, Macquarie University, Sydney, NSW, AUS

Research Interests

I am a sedimentologist with broad interests in volcanology, basin evolution, petrology, tectonics and Earth history. My research integrates field mapping, stratigraphy, petrography, geochemistry, and geochronology to investigate the sedimentary and tectono-magmatic evolution of the Earth. A specific research objective of mine is to better understand eruption dynamics, volcaniclast fragmentation and dispersal processes associated with submarine volcanism. 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.

Classes Taught

  • Physical Geology (GEOL 001)
  • Petrology (GEOL 122)
  • Sedimentology and Stratigraphy (GEOL 124)
  • Field Camp (GEOL 129)
  • Intro to GPS/GIS for Geologic Applications (GEOL 137)
  • Advanced Sedimentary Geology (GEOL 222)
  • Advanced Geology (GEOL 255)

Recent Activity (2011-2017)

Peer-reviewed Papers

      • Clague, D.A., Paduan, J.B., Caress, D.W., Chadwick Jr., W.W., Le Saout, M., Dreyer, B.M., and Portner, R.A., 2017, High-resolution AUV mapping and targeted ROV observations of three historical lava flows at Axial Seamount: Oceanography, v. 30, no. 4, p. 82-99. 
      • Portner, R.A., Clague D.A., Helo C., Dreyer, B. D., Paduan, J.B., 2015, Contrasting styles of deep-marine pyroclastic eruptions revealed from Axial Seamount push core records: Earth and Planetary Science Letters, v. 423, p. 219-231, DOI: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, p. 3364 3391, DOI: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, p. 28, DOI: 10.1007/s00445-014-0845-3
      • Clague, D.A., Dreyer, B.M., Paduan, J.B., Chadwick Jr., W.W., Caress, D.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: 10.1002/ggge.20240
      • Portner, R.A., Dickinson, J.A., Daczko, N.R., 2011, Interaction of gravity flows with a rugged mid­ocean ridge seafloor: an outcrop example from Macquarie Island: Journal of Sedimentary Research, May 2011, v. 81 (5), p. 355-375, DOI: 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, DOI: 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, DOI: 10.1016/j.lithos.2011.07.017
      • Portner, R.A., Hendrix, M.S., Stalker, J.C., Miggins, D.P., 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, DOI: 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, DOI: 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, DOI: 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, DOI: 10.1016/j.sedgeo.2009.02.001
      • Portner, R.A., and 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, p. 17, 1:24,000.