Professor of Earth Sciences
Environment, oceans and climate
Isotopes and Climate
Telephone: +44 1865 272 057
(PA: Sara Tennakoon)
I am a geochemist researching climate change and the carbon cycle.
Paleoclimate: I develop and refine geochemical proxies to understand the history of the past environment. These include radioactive isotopes to study rates of processes such as ocean circulation, and stable-isotopes to understand variables such as past rainfall or weathering. I also construct timescales for these proxy-records, and I run a leading U-series-chronology lab dating the history of sea level and of high-resolution climate records in stalagmites. I collaborate with ocean modellers to better understand and apply paleoclimate proxies, particularly those based on U-series nuclides. The unifying goal of this work is to use paleoclimate to better understand the processes controlling climate change. A particular recent interest in this area is to understand the influence of seasonality through very high resolution paleoclimate records. This complements long-standing interests in the response of the climate system at orbital and millennial timescales.
Ocean chemistry: My interest in ocean chemistry links to paleoclimate because it provides critical information about the proxies used for paleoclimate, and also because the oceans play such a critical role in driving climate via the carbon cycle. By making appropriate measurements in the water column and underlying core-top sediments, I assess the calibration, limitations and uncertainty on paleoproxies such as 230Th normalization, Si isotopes, and Mg/Ca. I also research the iron cycle in the oceans – so important for its role as a limiting nutrient – assessing the fluxes of Fe into the ocean from atmosphere, land and sediment. More recently, though collaboration with ocean modellers at Oxford, I have started to pursue work on the inorganic carbon system in the oceans, including the sensitivity of future ocean carbon uptake and the appropriateness of some ocean geoengineeering schemes.
Selected Publications (Extended Publications)
- Horner, TJ, Lee, RB, Henderson, GM, Rickaby, RE, (2013) ‘Nonspecific uptake and homeostasis drive the oceanic cadmium cycle.’, Proc Natl Acad Sci U S A. pp. 2500-2505 doi: 10.1073/pnas.1213857110
- Vaks, A, Gutareva, OS, Breitenbach, SF, Avirmed, E, Mason, AJ, Thomas, AL, Osinzev, AV, Kononov, AM, Henderson, GM, (2013) ‘Speleothems reveal 500,000-year history of Siberian permafrost.’, Science. pp. 183-186 doi: 10.1126/science.1228729
- Deschamps, P, Durand, N, Bard, E, Hamelin, B, Camoin, G, Thomas, AL, Henderson, GM, Okuno, J, Yokoyama, Y, (2012) ‘Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago.’, Nature. pp. 559-564 doi: 10.1038/nature10902
- Liu, Y-H, Henderson, GM, Hu, C-Y, Mason, AJ, Charnley, N, Johnson, KR, Xie, S-C, (2013) ‘Links between the East Asian monsoon and North Atlantic climate during the 8,200 year event’, NATURE GEOSCIENCE. pp. 117-120 doi: 10.1038/NGEO1708
- Blattler, CL, Henderson, GM, Jenkyns, HC, (2012) ‘Explaining the Phanerozoic Ca isotope history of seawater’, GEOLOGY. pp. 843-846 doi: 10.1130/G33191.1
- Hsieh, Y-T, Henderson, GM, Thomas, AL, (2011) ‘Combining seawater Th-232 and Th-230 concentrations to determine dust fluxes to the surface ocean’, EARTH AND PLANETARY SCIENCE LETTERS. pp. 280-290 doi: 10.1016/j.epsl.2011.10.022
- Negre, C, Zahn, R, Thomas, AL, Masqué, P, Henderson, GM, Martínez-Méndez, G, Hall, IR, Mas, JL, (2010) ‘Reversed flow of Atlantic deep water during the Last Glacial Maximum.’, Nature. pp. 84-88 doi: 10.1038/nature09508
- Thomas, AL, Henderson, GM, Deschamps, P, Yokoyama, Y, Mason, AJ, Bard, E, Hamelin, B, Durand, N, Camoin, G, (2009) ‘Penultimate deglacial sea-level timing from uranium/thorium dating of Tahitian corals.’, Science. pp. 1186-1189 doi: 10.1126/science.1168754