Christian Ohneiser staff page, Our people, Department of Geology, University of Otago, New Zealand

MSc, PhD (Otago)

Paleomagnetism
Paleoclimate/ocean reconstructions
Antarctic climate evolution

Email christian.ohneiser@otago.ac.nz
Tel +64 3 479 7350
Google Scholar Christian Ohneiser
ORCID orcid.org/0000-0002-2781-2522

Research interests

My research focuses on reconstructing the history of Earth’s climate system and geomagnetic field from sedimentary records on timescales of 10’s to millions of years. The research involves expeditions on research ships around New Zealand and Pacific Ocean and to remote field areas in Antarctica.

I study sedimentary records and apply paleomagnetic and geochemical techniques to date sediments and reconstruct under what climatic conditions they were deposited. Recent paleoclimate studies demonstrate that past environmental changes have occurred quickly therefore we require techniques that can achieve centennial to millennial-scale correlations between sedimentary records separated by large distances and deposited millions of years ago. In parallel, environmental magnetic, geochemical and sedimentological studies can reveal changes in sediment source, erosion rate, and changes in ocean circulation such as current strength and direction.

Current research projects

Southern Ocean circulation reconstructions

Antarctica plays an important role in regulating earth’s climate. The cold ice sheets interact with the ocean and are the powerhouse for global deep circulation which controls our weather and how heat is distributed around the world.

Antarctic Bottom Water (AABW) is a major component of the global thermohaline ocean circulation. Changes in its strength modify the global heat distribution and can have a direct impact on earth’s climate. Deep waters at the Antarctic margin have warmed and freshened in recent decades, and export rates have slowed. We don’t know if this is part of the Southern Ocean’s natural variability or something new. I am working with other researchers to examine the long-term variability and sensitivity of AABW production to changes in the surface conditions. The aim is to determine the spectrum of natural (pre-industrial) AABW production variability in order to place the recent observations in a long term context. The tools we use include magnetic mineralogy and fabric studies to understand changes in deep current strength, sedimentologic studies to reconstruct ice rafted debris and organic geochemical studies to reconstruct ocean surface temperature.

Reconstruction of the Ross Ice Shelf history

The Ross Ice shelf is the largest floating ice shelf in the world but rising ocean temperatures and changing ocean circulation patterns in the Ross Embayment may cause it become unstable in the future. How quickly the ice shelf may retreat is unknown but geological reconstructions of the most recent retreat phase at the end of the last ice shelf can help put constraints on future retreat scenarios. This project uses short sediment cores collected from the Ross Embayment and from beneath the Ross Ice Shelf to date the most recent ice shelf retreat and reconstruct the oceanographic changes which have occurred since.

New Zealand paleoclimate reconstructions

We have inherited a collection of pristine minerals industry sedimentary drill cores which are unique archives of New Zealand’s climate over last 55 million years. Over this period global average temperatures have reduced dramatically in parallel with decreasing atmospheric CO2 concentrations. The aim of this project is to understand better the sensitivity of the climate system to changing atmospheric CO2 concentrations known as the ‘climate sensitivity’. At the moment we are focusing on reconstructing the Eocene Climatic Optimum (c. 50 million years ago) when atmospheric CO2 was high (c. 1000 ppm) and the climate was much warmer than today.

Research Under the Antarctic Science Platform

Global mean temperatures are increasing and will continue to do so until greenhouse gas emissions are reduced significantly. Antarctica’s ice sheet are sensitive to subtle changes in temperature and have the capability to raise global sea-level significantly. Knowing how the Antarctic ice sheet will respond in the future is essential but to determine that we need to look at environmental records of how the Antarctic ice sheets and surrounding ocean have changed in the past. The multi-institution Antarctic Science Platform project ‘Antarctic Ice Dynamics – Past, Present, and Future’ uses a range of geological and geophysical techniques to investigate past changes and present-day ice sheet behaviour.
Visit the multi-institution Antarctic Science Platform website.

Field working the Lower Taylor Valley under the Qmap 22 geological mapping expedition. Photo: Dougal Townsend.

Sediment coring beneath the Ross Ice Shelf at HWD-2 for the NZARI Ross Ice Shelf Programme. Photo: Christina Hulbe.

Sediment core sampling at Florida State University in Tallahassee.

Core Scanning X-ray Fluorescence Analysis of Ocean Drilling Program Core 1101 at the IODP core repository in College Station Texas.

Research facilities

The Department of Geology has growing and complementary research capability which includes an analytical core repository, organic geochemical research facility and a paleomagnetic research facility. Additional facilities listed here.

The Otago Paleomagnetic Research Facility
The Department of Geology contains a state of the art magnetic research facility which include a superconducting magnetometer for measuring continuous and discrete samples and a vibrating sample magnetometer.

Ohneiser_IPaleoMagLab image

Postgraduate research opportunities

Are you interested in joining us for postgraduate study on sedimentary successions and paleoenvironmental reconstructions? We have several project opportunities waiting for you. The University of Otago offers scholarships to local and international students which cover tuition and provide a competitive stipend. For more information visit the Otago scholarships web page or email me for more information.

Sediment sampling At the Hogg Glacier, Antarctica.

The RV Joides Resolution at night in Honolulu before departing on IODP Expedition 320.

Teaching

* Course Coordinator

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Publications

Beltran, C., Sicre, M.-A., Ohneiser, C., & Sainz, M. (2021). A composite Pliocene record of sea surface temperature in the central Mediterranean (Capo Rossello composite section – South Sicily). Sedimentary Geology. Advance online publication. doi: 10.1016/j.sedgeo.2021.105921

Hulbe, C., Dunbar, G., Horgan, H., Levy, R., Mandeno, D., Ohneiser, C., … Stevens, C. (2021). The Aotearoa New Zealand Ross Ice Shelf research programme: Connecting modern process studies with past and future ice sheet system behaviour [Keynote]. Proceedings of the New Zealand Antarctic Science Conference: Connecting through change. (pp. 28-29). Retrieved from https://www.antarcticanz.govt.nz/nzasc21

Ohneiser, C. (2020). Obliquity pacing of Antarctic glaciations during the Quaternary. Proceedings of the Geoscience Society of New Zealand (GSNZ) Annual Conference. Retrieved from https://confer.eventsair.com/gsnz2020

Brenna, M., Ohneiser, C., Gorman, A., & Palin, M. (2020). Geothermal energy from extinct volcanoes: The Dunedin experiment. Proceedings of the 14th Annual Otago Energy Research Centre (OERC) Symposium: New Energy Futures post COVID-19. Retrieved from https://www.otago.ac.nz/oerc

Martin, A., Dunbar, G., Hulbe, C., Ohneiser, C., Grant, G., & Brandt, S. (2020). Provenance of gravel- and sand-sized sediment from both the ice shelf and shallowest seafloor at the HWD-2b site, mid Ross Ice Shelf, Antarctica. Proceedings of the Scientific Committee on Antarctic Research (SCAR) Open Science Conference. 1539. Retrieved from https://www.scar2020.org

Journal - Research Article

Beltran, C., Golledge, N. R., Ohneiser, C., Kowalewski, D. E., Marie-Alexandrine, S., Hageman, K. J., Smith, R., Wilson, G. S., & Mainié, F. (2020). Southern Ocean temperature records and ice-sheet models demonstrate rapid Antarctic ice sheet retreat under low atmospheric CO2 during Marine Isotope Stage 31. Quaternary Science Reviews, 228, 106069. doi: 10.1016/j.quascirev.2019.106069

Journal - Research Article

Ohneiser, C., & Tapia, C. (2020). Diagenesis of magnetic minerals at the Southwest Pacific DSDP Site 277. New Zealand Journal of Geology & Geophysics, 63(2), 250-261. doi: 10.1080/00288306.2019.1665075

Journal - Research Article

Ohneiser, C., Wilson, G. S., Beltran, C., Dolan, A. M., Hill, D. J., & Prebble, J. G. (2020). Warm fjords and vegetated landscapes in early Pliocene East Antarctica. Earth & Planetary Science Letters, 534, 116045. doi: 10.1016/j.epsl.2019.116045

Journal - Research Article

Perkins, E. J., Gorman, A. R., Tidey, E. J., Wilson, G. S., Ohneiser, C., Moy, C. M., Riesselman, C. R., Gilmer, G., & Ross, B. S. (2020). High-resolution seismic imaging reveals infill history of a submerged Quaternary fjord system in the subantarctic Auckland Islands, New Zealand. Quaternary Research, 93(1), 255-266. doi: 10.1017/qua.2019.58

Journal - Research Article

Stevens, C., Hulbe, C., Brewer, M., Stewart, C., Robinson, N., Ohneiser, C., & Jendersie, S. (2020). Ocean mixing and heat transport processes observed under the Ross Ice Shelf control its basal melting. PNAS, 117(29), 16799-16804. doi: 10.1073/pnas.1910760117

Journal - Research Article

Cole, R. P., Ohneiser, C., White, J. D. L., Townsend, D. B., & Leonard, G. S. (2019). Paleomagnetic evidence for cold emplacement of eruption-fed density current deposits beneath an ancient summit glacier, Tongariro volcano, New Zealand. Earth & Planetary Science Letters, 522, 155-165. doi: 10.1016/j.epsl.2019.07.004

Journal - Research Article

Gangl, S. K., Moy, C. M., Stirling, C. H., Jenkyns, H. C., Crampton, J. S., Clarkson, M. O., Ohneiser, C., & Porcelli, D. (2019). High-resolution records of Oceanic Anoxic Event 2: Insights into the timing, duration and extent of environmental perturbations from the palaeo-South Pacific Ocean. Earth & Planetary Science Letters, 518, 172-182. doi: 10.1016/j.epsl.2019.04.028

Journal - Research Article

Jovane, L., Florindo, F., Acton, G., Ohneiser, C., Sagnotti, L., Strada, E., … Wilson, G. S., … Passchier, S. (2019). Miocene glacial dynamics recorded by variations in magnetic properties in the ANDRILL‐2A drill core. Journal of Geophysical Research: Solid Earth, 124, 2297-2312. doi: 10.1029/2018JB016865

Journal - Research Article

Ohneiser, C., Yoo, K.-C., Albot, O. B., Cortese, G., Riesselman, C., Lee, J. I., … Bollen, M., … Beltran, C., … Wilson, G. S. (2019). Magneto-biostratigraphic age models for Pleistocene sedimentary records from the Ross Sea. Global & Planetary Change, 176, 36-49. doi: 10.1016/j.gloplacha.2019.02.013

Journal - Research Article

Tapia, C. A., Grant, G. R., Turner, G. M., Sefton, J. P., Naish, T. R., Dunbar, G., & Ohneiser, C. (2019). High-resolution magnetostratigraphy of mid-Pliocene (3.3-3.0 Ma) shallow-marine sediments, Whanganui Basin, New Zealand. Geophysical Journal International, 217(1), 41-57. doi: 10.1093/gji/ggz004

Journal - Research Article

Grant, G. R., Sefton, J. P., Patterson, M. O., Naish, T. R., Dunbar, G. B., Hayward, B. W., … Ohneiser, C., & Turner, G. M. (2018). Mid- to late Pliocene (3.3–2.6 Ma) global sea-level fluctuations recorded on a continental shelf transect, Whanganui Basin, New Zealand. Quaternary Science Reviews, 201, 241-260. doi: 10.1016/j.quascirev.2018.09.044

Journal - Research Article

Martin, A. P., Ohneiser, C., Turnbull, R. E., Strong, D. T., & Demler, S. (2018). Soil magnetic susceptibility mapping as a pollution and provenance tool: An example from southern New Zealand. Geophysical Journal International, 212(1), 1225-1236. doi: 10.1093/gji/ggx484

Journal - Research Article

Ohneiser, C., & Wilson, G. S. (2018). Eccentricity-paced Southern Hemisphere glacial-interglacial cyclicity preceding the middle Miocene climatic transition. Paleoceanography & Paleoclimatology, 33, 795-806. doi: 10.1029/2017PA003278

Journal - Research Article

Patterson, M. O., McKay, R., Naish, T., Bostock, H. C., Dunbar, R., Ohneiser, C., … Wilson, G., & Caballero-Gill, R. (2018). A Southwest Pacific perspective on long-term global trends in Pliocene-Pleistocene stable isotope records. Paleoceanography & Paleoclimatology, 33(7), 825-839. doi: 10.1029/2017pa003269

Journal - Research Article

Beltran, C., Ohneiser, C., Hageman, K. J., & Scanlan, E. (2016). Evolution of the southwestern Pacific surface waters during the early Pleistocene. New Zealand Journal of Geology & Geophysics, 59(4), 514-521. doi: 10.1080/00288306.2016.1195756

Journal - Research Article

Levy, R., Harwood, D., Florindo, F., Sangiorgi, F., Tripati, R., von Eynatten, H., … and SMS Science Team, including Ohneiser, C., Riesselman, C., & Wilson, G. (2016). Antarctic ice sheet sensitivity to atmospheric CO₂ variations in the early to mid-Miocene. PNAS, 113(13), 3453-3458. doi: 10.1073/pnas.1516030113

Journal - Research Article

von Lichtan, I., White, J. D. L., Manville, V., & Ohneiser, C. (2016). Giant rafted pumice blocks from the most recent eruption of Taupo volcano, New Zealand: Insights from palaeomagnetic and textural data. Journal of Volcanology & Geothermal Research, 318, 73-88. doi: 10.1016/j.jvolgeores.2016.04.003

Journal - Research Article

Ohneiser, C., Florindo, F., Stocchi, P., Roberts, A. P., DeConto, R. M., & Pollard, D. (2015). Antarctic glacio-eustatic contributions to late Miocene Mediterranean desiccation and reflooding. Nature Communications, 6, 8765. doi: 10.1038/ncomms9765

Journal - Research Article

Ohneiser, C., Wilson, G. S., & Cox, S. C. (2015). Characterisation of magnetic minerals from southern Victoria Land, Antarctica. New Zealand Journal of Geology & Geophysics, 58(1), 52-65. doi: 10.1080/00288306.2014.990044

Journal - Research Article

Yamamoto, Y., Yamazaki, T., Acton, G. D., Richter, C., Guidry, E. P., & Ohneiser, C. (2014). Palaeomagnetic study of IODP Sites U1331 and U1332 in the equatorial Pacific: Extending relative geomagnetic palaeointensity observations through the Oligocene and into the Eocene. Geophysical Journal International, 196(2), 694-711. doi: 10.1093/gji/ggt412

Journal - Research Article

Brachfeld, S., Pinzon, J., Darley, J., Sagnotti, L., Kuhn, G., Florindo, F., Wilson, G., Ohneiser, C., … Joseph, L. (2013). Iron oxide tracers of ice sheet extent and sediment provenance in the ANDRILL AND-1B drill core, Ross Sea, Antarctica. Global & Planetary Change, 110, 420-433. doi: 10.1016/j.gloplacha.2013.09.015

Journal - Research Article

Channell, J. E. T., Ohneiser, C., Yamamoto, Y., & Kesler, M. S. (2013). Oligocene-Miocene magnetic stratigraphy carried by biogenic magnetite at sites U1334 and U1335 (equatorial Pacific Ocean). Geochemistry, Geophysics, Geosystems, 14(2), 265-282. doi: 10.1029/2012gc004429

Journal - Research Article

Guidry, E. P., Richter, C., Acton, G. D., Channell, J. E. T., Evans, H. F., Ohneiser, C., … Yamazaki, T. (2013). Oligocene-Miocene magnetostratigraphy of deep-sea sediments from the Equatorial Pacific (IODP Site U1333). Geological Society, London, Special Publications, 373, 13-27. doi: 10.1144/sp373.7

Journal - Research Article

Ohneiser, C., Acton, G., Channell, J. E. T., Wilson, G. S., Yamamoto, Y., & Yamazaki, T. (2013). A middle Miocene relative paleointensity record from the Equatorial Pacific. Earth & Planetary Science Letters, 374, 227-238. doi: 10.1016/j.epsl.2013.04.038

Journal - Research Article

Levy, R., Cody, R., Crampton, J., Fielding, C., Golledge, N., Harwood, D., … Ohneiser, C., Wilson, G., … Winter, D. (2012). Late Neogene climate and glacial history of the Southern Victoria Land coast from integrated drill core, seismic and outcrop data. Global & Planetary Change, 80-81, 61-84. doi: 10.1016/j.gloplacha.2011.10.002

Journal - Research Article

Ohneiser, C., & Wilson, G. (2012). Revised magnetostratigraphic chronologies for New Harbour drill cores, southern Victoria Land, Antarctica. Global & Planetary Change, 82-83, 12-24. doi: 10.1016/j.gloplacha.2011.11.007

Journal - Research Article

Pälike, H., Lyle, M. W., Nishi, H., Raffi, I., Ridgwell, A., Gamage, K., … Beltran, C., … Ohneiser, C., … Zeebe, R. E. (2012). A Cenozoic record of the equatorial Pacific carbonate compensation depth. Nature, 488(7413), 609-614. doi: 10.1038/nature11360

Journal - Research Article

Wilson, G. S., Levy, R. H., Naish, T. R., Powell, R. D., Florindo, F., Ohneiser, C., … Riesselman, C., … Wise, S. (2012). Neogene tectonic and climatic evolution of the Western Ross Sea, Antarctica: Chronology of events from the AND-1B drill hole. Global & Planetary Change, 96-97, 189-203. doi: 10.1016/j.gloplacha.2012.05.019

Journal - Research Article

Passchier, S., Browne, G., Field, B., Fielding, C. R., Krissek, L. A., Panter, K., … and ANDRILL-SMS Science Team, including Ohneiser, C., Palin, M., Riesselman, C., & Wilson, G. (2011). Early and middle Miocene Antarctic glacial history from the sedimentary facies distribution in the AND-2A drill hole, Ross Sea, Antarctica. Geological Society of America Bulletin, 123(11-12), 2352-2365. doi: 10.1130/B30334.1

Journal - Research Article

Frank, T. D., Gui, Z., and the ANDRILL SMS Science Team, including Ohneiser, C., Palin, M., Riesselman, C., & Wilson, G. (2010). Cryogenic origin for brine in the subsurface of southern McMurdo Sound, Antarctica. Geology, 38(7), 587-590. doi: 10.1130/G30849.1

Journal - Research Article

Field, B. D., Crundwell, M. P., Lyon, G. L., Mildenhall, D. C., Morgans, H. E. G., Ohneiser, C., Wilson, G. S., … Chanier, F. (2009). Middle Miocene paleoclimate change at Bryce Burn, southern New Zealand. New Zealand Journal of Geology & Geophysics, 52(4), 321-333. doi: 10.1080/00288306.2009.9518461

Journal - Research Article

Naish, T., Powell, R., Levy, R., Wilson, G., Scherer, R., Talarico, F., … Ohneiser, C., … Riesselman, C., … Williams, T. (2009). Obliquity-paced pliocene west antarctic ice sheet oscillations. Nature, 458(7236), 322-328. doi: 10.1038/nature07867

Journal - Research Article

Acton, G., Crampton, J., Di Vincenzo, G., Fielding, C. R., Florindo, F., Hannah, M., … Ohneiser, C., … Riesselman, C., … Wilson, G. S., … and the ANDRILL-SMS Science Team. (2008-2009). Preliminary integrated chronostratigraphy of the AND-2A core, ANDRILL Southern McMurdo Sound Project, Antarctica. Terra Antartica, 15(1-2), 211-220.

Journal - Research Article

Acton, G., Florindo, F., Jovane, L., Lum, B., Ohneiser, C., Sagnotti, L., … Wilson, G. S., and the ANDRILL-SMS Science Team. (2008). Palaeomagnetism of the AND-2A Core, ANDRILL southern McMurdo Sound Project, Antarctica. Terra Antartica, 15(1), 193-210.

Journal - Research Article

Ohneiser, C., Wilson, G. S., Field, B. D., & Crundwell, M. P. (2008). A new high-resolution, middle Miocene magnetostratigraphy from western Southland, New Zealand. New Zealand Journal of Geology & Geophysics, 51(3), 261-274. doi: 10.1080/00288300809509864

Journal - Research Article

Wilson, G. S., Florindo, F., Sagnotti, L., & Ohneiser, C. (2007). Palaeomagnetism of the AND-1B core, ANDRILL McMurdo Ice Shelf Project, Antartica. Terra Antartica, 14(3), 289-296.

Journal - Research Article

Wilson, G. S., Levy, R., Browne, G., Cody, R., Dunbar, N., Florindo, F., … Ohneiser, C., … and the ANDRILL-MIS Science Team. (2007). Preliminary integrated chronostratigraphy of the AND-1B core, ANDRILL McMurdo Ice Shelf Project, Antarctica. Terra Antartica, 14(3), 297-316.

Journal - Research Article