USAP-DC

Dunbar/1543454 Antarctic ice cores offer unparalleled records of earth?s climate back to almost one million years and perhaps beyond. Layers of volcanic ash (tephra) embedded in glacial ice can be used to establish an accurate ice core chronology. In order to use a visible or ultrafine volcanic ash layer as a time-stratigraphic marker, a unique geochemical fingerprint must be established, and this forms the basis of our research. This award will investigate the volcanic record in the 1751 m ice core that was completed at the South Pole during the 2015/16 field season. The core is in an ideal location to link the existing, established, volcanic records in East and West Antarctica, and therefore to connect and integrate those records, allowing the climate records of ice cores to be directly compared, as well as to focus research on the most widespread and significant volcanic eruptions from West Antarctica. Tephra derived from well-dated, large, tropical volcanic eruptions that may have had an impact on climate will also be studied. Recent success in identifying and analyzing very fine ash particles from these types of eruptions makes it likely that we will be able to pinpoint some of these eruptions, which will allow the sulfate peaks associated with these layers to be positively identified and dated. Volcanic forcing time series developed from earlier South Pole ice cores based on preserved sulfate were crucial for testing climate models, but without tephra analysis, the origin of these layers remains uncertain. Work on the tephra layers in the South Pole ice core has a number of significant specific objectives, some with practical applications to the basic science goals of Antarctic ice coring, and others that represent independent scientific contributions in their own right. These include: (1) providing independently dated time-intervals in the core, particularly for the deepest ice, (2) quantitatively linking tephra records across Antarctica with the goal of allowing direct and robust climate comparisons between these different parts of the continent, (3) providing information for large local eruptions, that will lead to direct estimates of eruption magnitude and dispersal patterns of Antarctic volcanoes, several of which will likely erupt again. The initial stages of the work will be carried out by identifying silicate-bearing horizons in the ice core, using several methods. Once found, silicate particles will be imaged so that morphological characteristics of the particles can be used to identify volcanic origin. Particles identified as tephra will then be chemically analyzed using electron microprobe and laser ablation ICP-MS. Samples that yield a robust chemical fingerprint will be statistically correlated to known eruptions, and this will be used to address the goals described above. Broader impacts of this project fall into the areas of education of future generation of researchers, outreach and international cooperation. These activities will continue to promote forward progress in integrating the Antarctic tephra record and more broadly tying it to the global volcanic record.

Person	Role
Dunbar, Nelia	Investigator
Iverson, Nels	Investigator
Kurbatov, Andrei V.	Investigator and contact

Antarctic Glaciology	Award # 1543454
Antarctic Glaciology	Award # 1543361

USAP-1543454_1

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Cryptotephra in SPC-14 ice core	Excel	exists
USAP-DC	SPICEcore visable tephra	Excel	exists

1. Winski, D. A., Fudge, T. J., Ferris, D. G., Osterberg, E. C., Fegyveresi, J. M., Cole-Dai, J., Thundercloud, Z., Cox, T. S., Kreutz, K. J., Ortman, N., Buizert, C., Epifanio, J., Brook, E. J., Beaudette, R., Severinghaus, J., Sowers, T., Steig, E. J., Kahle, E. C., Jones, T. R., Morris, V., Aydin, M., Nicewonger, M. R., Casey, K. A., Alley, R. B., Waddington, E. D., Iverson, N. A., Bay, R. C., and Souney, J. M. (2019). The SP19 Chronology for the South Pole Ice Core – Part 1: Volcanic matching and annual-layer counting. 15. Climate of the Past, 15. (doi:https://doi.org/10.5194/cp-15-1793-2019)
2. Dunbar, N.W., Iverson, N.A., Smellie, J.L., McIntosh, W.C., Zimmerer, M.J., Kyle, P.R. (2021). Active volcanoes of Marie Byrd Land. Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-Up 55. Smellie, J. L., Panter, K.S., and Geyer, A.. Geological Society of London. (DOI: 10.1144/M55-2019-29)
3. Blong, Russell J. and Kurbatov, Andrei V. "Steps and missteps on the path to a 1665–1668 CE date for the VEI 6 eruption of Long Island, Papua New Guinea" (2020). Journal of Volcanology and Geothermal Research, v.395. (doi:https://doi.org/10.1016/j.jvolgeores.2020.106828 )
4. Koffman, B. G., Dowd, Eleanor G. Osterberg, Erich C. Ferris, David G. Hartman, Laura H. Wheatley, Sarah D. Kurbatov, Andrei V. Wong, Gifford J. Markle, Bradley R. Dunbar, Nelia W. Kreutz, Karl J. Yates, Martin (2017). "Rapid transport of ash and sulfate from the 2011 Puyehue-Cordo Caulle (Chile) eruption to West Antarctica" J. Geophys. Res. v122. (DOI: 10.1002/2017JD026893 )
5. Hartman, Laura H. and Kurbatov, Andrei V. and Winski, Dominic A. and Cruz-Uribe, Alicia M. and Davies, Siwan M. and Dunbar, Nelia W. and Iverson, Nels A. and Aydin, Murat and Fegyveresi, John M. and Ferris, David G. and Fudge, T. J. and Osterberg, Erich C (2019). "Volcanic glass properties from 1459 C.E. volcanic event in South Pole ice core dismiss Kuwae caldera as a potential source" Scientific Reports, v.9. (doi:https://doi.org/10.1038/s41598-019-50939-x)
6. Lee, Mi Jung, Kyle, Philip R., Iverson, Nels A., Lee, Jong Ik, Han, Yeongcheol. (2019). "Rittmann volcano, Antarctica as the source of a widespread 1252 +/- 2 CE tephra layer in Antarctica ice" Earth and Planetary Science Letters , v.521 , p.169. (DOI: 10.1016/j.epsl.2019.06.002)
7. Piva, S. B., Barker, S. J., Iverson, N. A., Winton, V. H. L., Bertler, N. A. N., Sigl, M., Wilson, C. J. N., Dunbar, N. W., Kurbatov, A. V., Carter, L., Charlier, B. L. A., & Newnham, R. M. (2023). Volcanic glass from the 1.8 ka Taupō eruption (New Zealand) detected in Antarctic ice at ~ 230 CE. Scientific Reports, 13(1). (doi:10.1038/s41598-023-42602-3)