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Christian Ohneiser

Christian Ohneiser

PhD thesis: A source to sink investigation of the erosion, transport and deposition of magnetic minerals in the Ross Sea sector of Antarctica

Supervisor: Dr Gary S Wilson

Contact me: christian.ohneiser@otago.ac.nz

Finished PhD 2012

Research

Over the past 30 years several drilling projects (DVDP, DSDP, MSSTS, CIROS, CRP) have recovered sedimentary cores from the Ross embayment in an effort to understand the Cenozoic climate history of Antarctica and to determine its role in the global environmental system. The most recent is the ANDRILL initiative which recovered its first core during 2006-2007 austral summer. The two key questions in each of these paleoclimate drilling projects are, what is the depositional environment and ageof the sediment recovered. In order to answer these questions, and to understand the climate changes that have occurred in Antarctica, it is crucial to have accurate, high resolution age control of the recovered sedimentary cores.

Paleomagnetism is a powerful technique for developing precise age models in sedimentary successions because we have a precise (±5 kyrs) record of geomagnetic reversals back to 65 Ma and the reversals of the geomagnetic field are globally synchronous. Paleomagnetic records are also a powerful tool in the field of paleoclimatology as they can provide clues about erosion, transport and environment of deposition.

However, the paleomagnetic signals of sedimentary successions drilled from Antarctica have always been more difficult to interpret because we lack a thorough understanding of source to sink evolution of the paleomagnetic signal. Matters are worsened by the nature of the sediment being drilled (poorly cemented diamictites and diatomites) and by the core recovery procedure which often results in magnetic overprints and a noisy paleomagnetic signal. Despite these difficulties paleomagnetism is still the critical tool underpinning these efforts.

The objective for this study is to determine the relationship between the sediment source and the collected core samples for the ANDRILL, CRP, CIROS, MSSTS, DVDP and DSDP cores. More specifically, to determine how the source rocks, depositional environment, diagenetic conditions and ambient magnetic field at the time of sediment deposition affect the magnetic signature.

The magnetic remanence will be measured of samples collected from the core. The magnetic mineralogy, distribution and grainsize will be determined for the core using Isothermal Remanence Magnetisation (IRM), hysteresis and temperature dependence of magnetic susceptibility experiments. Anisotropy of Magnetic Susceptibility (AMS) will be measured to determine peleocurrent directions and to determine how the magnetic fabric affects the remanence. Bulk samples will be collected in the field from source rocks, from under the ice shelf and from the MIS-1 core to determine the lithological nature of the source and sink rocks and to investigate their relationship to the geomagnetic field at the time of deposition and vulnerability during core recovery.

ANDRILL drill rig on the McMurdo Ice Shelf during the 2006 drilling season.

ANDRILL drill rig on the McMurdo Ice Shelf during the 2006 drilling season.

Scientific Publications and Reports

  • Ohneiser, C., and Wilson, G.S., 2012. Revised magnetostratigraphic chronologies of the DVDP-10, DVDP-11 and CIROS-2 drill cores from southern Victoria Land Antarctica: Global and Planetary Change. doi:10.1016/j.gloplacha.2011.11.007
  • Levy, R. H., Cody, R., Crampton, J., Fielding, C. R., Golledge, N., Harwood, D. M., Henrys, S., McKay, R., Naish, T., Ohneiser, C., Wilson, G., Wilson, T., and Winter, D. D., 2012. Late Neogene climate and glacial history of the Southern Victoria Land coast from integrated drill core, seismic and outcrop data. Global and Planetary Change. v. 80, p. 61-84.
  • Westerhold, T., Röhl, U., Wilkens, R., Pälike, H., Lyle, M., Dunkley Jones, T., Bown, P., Moore, T., Kamikuri, S., Acton, G., Ohneiser, C.,Yamamoto, Y., Richter, C., Fitch, P., Scher, H., Liebrand, D., and Expeditions 320/321 scientists., 2011. Revised composite depth scales and integration of IODP Sites U1331, U1332, U1333, U1334 and ODP Sites 1218, 1219, 1220. in Proceedings of the Integrated Ocean Drilling Program, Volume 320/321, doi:10.2204/iodp.proc.320321.201.2011
  • Pälike, H., Nishi, H., Lyle, M., Raffi, I., Klaus, A., Gamage, K., and the Expedition 320/321 Scientists, 2009. Pacific Equatorial Transect. IODP Prel. Rept., 320.
  • Field, B.D., Crundwell, M.P., Lyon, G.L., Mildenhall, D.C., Morgans, H.E.G., Ohneiser, C., Wilson, G.S., Kennett, J.P., Chanier, F., 2009: Middle Miocene paleoclimate change at Bryce Burn, southern New Zealand: New Zealand Journal of Geology and Geophysics, v. 52, p. 321-333.
  • Naish, T., Powell, R., Levy, R., Wilson, G., Scherer, R., Talarico, F., Krissek, L., Niessen, F., Pompilio, M., Wilson, T., Carter, L., DeConto, R., Huybers, P., McKay, R., Pollard, D., Ross, J., Winter, D., Barrett, P., Browne, G., Cody, R., Cowan, E., Crampton, J., Dunbar, G., Dunbar, N., Florindo, F., Gebhardt, C., Graham, I., Hannah, M., Hansaraj, D., Harwood, D., Helling, D., Henrys, S., Hinnov, L., Kuhn, G., Kyle, P., Laufer, A., Maffioli, P., Magens, D., Mandernack, K., McIntosh, W., Millan, C., Morin, R., Ohneiser, C., Paulsen, T., Persico, D., Raine, I., Reed, J., Riesselman, C., Sagnotti, L., Schmitt, D., Sjunneskog, C., Strong, P., Taviani, M., Vogel, S., Wilch, T., and Williams, T.2009. Obliquity-paced Pliocene West Antarctic ice sheet oscillations: Nature, v. 458, p. 322-328.
  • Ohneiser, C., Wilson, G.S., Field, B.D., and Crundwell, M.P., 2008. A new high-resolution, middle Miocene magnetostratigraphy from western Southland, New Zealand: New Zealand Journal of Geology and Geophysics, v. 51, p. 261-274.
  • Acton, G., Crampton, J., Vincenzo, G., Fielding, C. R., Florindo, F., Hannah, M., Har- wood, D., Ishman, S., Johnson, K., Jovane, L., Levy, R., Lum, B., Marcano, M., Mukasa, S. B., Ohneiser, C., Olney, M. P., Riesselman, C., Sagnotti, L., Stefano, C., Strada, E., Taviani, M., Tuzzi, E., Verosub, K. L., Wilson, G. S., Zattin, M., and the ANDRILL SMS Science team (2008). Preliminary integrated chronostratigraphy of the AND-2A core, Andrill Southern McMurdo Sound Project, Antarctica. Terra Antartica, v. 15, p. 211–220.
  • Acton, G., Florindo, F., Jovane, L., Jovane, L., Ohneiser, C., Sagnotti, L., Strada, E., Verosub, K. 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, v. 15, p. 193–210.
  • Wilson, G.S., Levy, R.H., Browne, G., Cody, R., Dunbar, G., Florindo, F., Henrys, S., Graham, I., McIntosh, W.C., McKay, R., Naish, T., Ohneiser, C., Powell, R.D., Ross, J., Sagnotti, L., Scherer, R.P., Sjunnesskog, C., Strong, C.P., Taviani, M., Winter, D.M., and the ANDRILL MIS Science team., 2007. Preliminary Integrated Chronostratigraphy of the AND-1B Core, ANDRILL McMurdo Ice Shelf Project, Antarctica: Terra Antartica, v. 14, p. 297-316.
  • Wilson, G.S., Florindo, F. Sagnotti, L., Ohneiser, C., 2007. ANDRILL McMurdo Ice Shelf Project, Palaeomagnetism of the AND-1B Core, ANDRILL McMurdo Ice Shelf Project, Antarctica: Terra Antartica, v. 14, p. 289-296.
  • Proust, J-n., Lamarche, G., Migneon, S., Neil, H., and Shipboard party., 2006. MD 152/ MATACORE on R/V Marion-Dufresne.

Presentations at Conferences

  • Ohneiser, C., and Wilson, G.S., 2011. Revised magnetostratigraphic chronologies for New Harbour Drill cores, Southern Victoria Land, Antarctica. International Symposium on Antarctic Earth Sciences (ISAES). Edinburgh, UK.
  • Ohneiser, C., Acton, G., Channell, J.E.T., Evans, H., Richter, C., Wilson, G.S.,  Yamamoto, Y., Yamazaki, T., 2011. Evidence from IODP site U1336 for Eccentricity paced fluctuations of the carbonate compensation depth (CCD) during the middle Miocene. EXP 320, Science Integration Workshop. Paris, France.
  • Ohneiser, C., Acton, G., Channell, J.E.T., Evans, H., Richter, C., Yamamoto, Y., Yamazaki, T., and the Expedition 320/321 Scientists., 2010: Magnetostratigraphic Records from Eocene-Miocene Sediments Cored in the Equatorial Pacific: Initial Results from the Pacific Equatorial Age Transect (PEAT) IODP Exp 320/321. Australian Earth Sciences Convention 2010, Canberra, Australia.
  • Ohneiser, C., Wilson, G.S., and Florindo, F., 2010. Environmental magnetic evidence for a dynamic Taylor Glacier during the mid-Pliocene warm period. European Geophysical Union (EGU) Conference, Vienna, Austria.
  • Andrill SMS Science integration workshop. 2010. Erice, Italy.
  • Ohneiser, C., Acton, G., Channell, J.E.T., Evans, H., Richter, C., Yamamoto,  Y., Yamazaki, T., and the Expedition 320/321 Scientists., 2009: Magnetostratigraphic Records from Eocene-Miocene Sediments Cored in the Equatorial Pacific: Initial Results from the Pacific Equatorial Age Transect (PEAT) IODP Exp 320/321. Geological Society of New Zealand & New Zealand Geophysical Society Joint Annual Conference. Oamaru, New Zealand.
  • Andrill MIS Science integration workshop. 2009. Wellington, New Zealand.
  • Ohneiser, C., and  Wilson, G.S., 2008. An oceanographic record from Western-Southland, New Zealand of eccentricity-obliquity paced glaciations of the cryosphere during the middle Miocene.2008 International Conference on Rock Magnetism. Cargese, France.
  • Ohneiser, C., and  Wilson, G.S., 2007. A middle Miocene oceanographic record from Western-Southland, New Zealand of eccentricity-obliquity paced glaciations of the cryosphere. Geological Society of New Zealand & New Zealand Geophysical Society Joint Annual Conference. Tauranga, New Zealand.
  • Ohneiser, C., Wilson, G.S., Field, B.D., and Crundwell, M.P., 2006. Evidence for orbital pacing through the middle Miocene climatic deterioration from the Southwest Pacific. European Geophysical Union (EGU) Conference, Vienna, Austria. 2006.