Provenancing Dust in Ice Core records using Isotopes
Ice core records are an important foundational archive for paleoclimatology. Through them scientists have reconstructed high resolution atmospheric CO2 and temperature records covering hundreds of thousands of years. This captured ancient air allows unique direct access to paleo-atmospheric oxygen and carbon isotopic composition to a range of applications. Importantly, beyond these variables, ice cores also capture ancient transported aerosols/dust – allowing one to reconstruct dust origin, movement and ultimately past atmospheric circulation at a hemispheric scale.
Dust concentration variability can be a proxy for climate oscillations, including high temporal resolution oceanic oscillations (Pacific Decadal Oscillation; Reis et al. 2022) and crucial glacial/interglacial transitions (e.g. Holocene warm period following Late Glacial; Simonsen et al. 2019). Typically, cooler global temperatures result in significantly higher dust build-up in ice cores due to more arid conditions and mechanical weathering of source regions by the growth of ice sheets (Ruth et al. 2003). Whereas the particle size distribution provides evidence of transportation (Delmont et al. 2017).
The source of dust within ice cores (“provenancing”) can be predicted by analyzing the isotopic composition of various elements – including strontium (Sr) and neodymium (Nd) – which can be matched to geological mineralogy of potential dust sources (Svensson et al. 2000). In a recent study, Simonsen et al. (2019) analyzed Sr and Nd within an eastern Greenland ice core covering 120,000 years to establish dust source changes through time. They were able to pinpoint a singular dust origin for the cool periods of the record and reconstruct windflow across the continent as a result. Furthermore, during a prolonged warm, deglacial period (Late Glacial) and lower dust concentrations, the dust source changed to a more localized origin. This study demonstrates the potential strength of combining Sr and Nd isotopes with other ice core proxies in order to develop a comprehensive reconstruction of past climate events. Additional isotopes can provide more enriched information on dust sources, including Hafnium (Hf) – which can be particularly useful when Sr and Nd isotopes alone provide inconclusive results (Újvári et al. 2017, 2022).
Isobar Science provides Strontium(87Sr/86Sr) measurements in a variety of sample types, including mineral dust. The lab discontinued the Nd-Hf service starting January 2024.
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References
Delmonte, B., Paleari, C.I., Andò, S., Garzanti, E., Andersson, P.S., Petit, J.R., Crosta, X., Narcisi, B., Baroni, C., Salvatore, M.C. and Baccolo, G., (2017). Causes of dust size variability in central East Antarctica (Dome B): Atmospheric transport from expanded South American sources during Marine Isotope Stage 2. Quaternary Science Reviews, 168, pp.55-68.
Reis, R.S.D., da Rocha Ribeiro, R., Delmonte, B., Ramirez, E., Dani, N., Mayewski, P.A. and Simões, J.C., 2022. The Recent Relationships Between Andean Ice-Core Dust Record and Madeira River Suspended Sediments on the Wet Season. Frontiers in Environmental Science, 10, p.840884.
Ruth, U., Wagenbach, D., Steffensen, J.P. and Bigler, M., (2003). Continuous record of microparticle concentration and size distribution in the central Greenland NGRIP ice core during the last glacial period. Journal of Geophysical Research: Atmospheres, 108(D3).
Simonsen, M.F., Baccolo, G., Blunier, T., Borunda, A., Delmonte, B., Frei, R., Goldstein, S., Grinsted, A., Kjær, H.A., Sowers, T. and Svensson, A., (2019). East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat. Nature Communications, 10(1), p.4494.
Svensson, A., Biscaye, P.E. and Grousset, F.E., (2000). Characterization of late glacial continental dust in the Greenland Ice Core Project ice core. Journal of Geophysical Research: Atmospheres, 105(D4), pp.4637-4656.
Újvári, G., Wegner, W., Klötzli, U., Horschinegg, M. and Hippler, D., (2018). Sr‐Nd‐Hf isotopic analysis of< 10 mg dust samples: Implications for ice core dust source fingerprinting. Geochemistry, Geophysics, Geosystems, 19(1), pp.60-72.
Újvári, G., Klötzli, U., Stevens, T., Svensson, A., Ludwig, P., Vennemann, T., Gier, S., Horschinegg, M., Palcsu, L., Hippler, D. and Kovács, J., (2022). Greenland ice core record of last glacial dust sources and atmospheric circulation. Journal of Geophysical Research: Atmospheres, 127(15), p.e2022JD036597.
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