Professor Alex Halliday


Head of Mathematical, Physical and Life Sciences Division

Email: alex.halliday@earth.ox.ac.uk
TEL: +44 (1865) 272969
FAX: +44 (1865) 272072


Research Profile

I use isotope geochemistry to understand the origins of planets and the present day natural behaviour of the Earth by utilising mass spectrometry to measure small natural variations in atomic abundance. The main causes of such variations are radioactive decay, mass dependent fractionation, cosmic ray interactions and nucleosynthetic effects inherited from other stars. Such measurements provide powerful constraints on: (1) ages and rates of past processes, for example, the age of the Moon or the rate of cooling of the Earth; (2) the conditions under which certain objects form, for example, the past temperatures of the world's oceans and (3) the origins of various reservoirs, a kind of forensic fingerprinting of, for example, the nature of the source of the basalt magma being erupted in Hawaii.

Recent developments in this subject have been dominated by innovations in mass spectrometry that permit the study of elements previously inaccessible to precise analysis, facilitate more precise measurements, or achieve better spatial resolution. Most of my efforts in recent years have focussed on MC-ICPMS, a technique that combines the ionisation efficiency of the ICP source with the precision achievable with magnetic sector multiple collector mass spectrometry. This method has resulted in the first precise measurements of the isotopic compositions of many elements in the small quantities found in natural materials. The first such instrument formed the basis for our programme at the University of Michigan and the first large geometry MC-ICPMS was designed for our lab at the ETH in Zurich. In Oxford we have established new facilities for chemistry and mass spectrometry and these are shared with Gideon Henderson, Don Porcelli and Ros Rickaby. The new suite of labs and instruments is the largest of its kind world-wide, including six MC-ICPMS instruments.

Selected Publications

  • Nielsen, SG, Prytulak, J, Halliday, AN, (2011) 'Determination of Precise and Accurate V-51/V-50 Isotope Ratios by MC-ICP-MS, Part 1: Chemical Separation of Vanadium and Mass Spectrometric Protocols', GEOSTANDARDS AND GEOANALYTICAL RESEARCH. pp. 293-306 doi: 10.1111/j.1751-908X.2011.00106.x
  • Prytulak, J, Nielsen, SG, Halliday, AN, (2011) 'Determination of Precise and Accurate V-51/V-50 Isotope Ratios by Multi-Collector ICP-MS, Part 2: Isotopic Composition of Six Reference Materials plus the Allende Chondrite and Verification Tests', GEOSTANDARDS AND GEOANALYTICAL RESEARCH. pp. 307-318 doi: 10.1111/j.1751-908X.2011.00105.x
  • Hendry, KR, Georg, RB, Rickaby, REM, Robinson, LF, Halliday, AN, (2011) 'Deep ocean nutrients during the Last Glacial Maximum deduced from sponge silicon isotopic compositions (vol 292, pg 290, 2010)', EARTH AND PLANETARY SCIENCE LETTERS. pp. 253-254 doi: 10.1016/j.epsl.2010.12.023
  • Opfergelt, S, Eiriksdottir, ES, Burton, KW, Einarsson, A, Siebert, C, Gislason, SR, Halliday, AN, (2011) 'Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes: Lake Myvatn, Iceland', EARTH AND PLANETARY SCIENCE LETTERS. pp. 73-82 doi: 10.1016/j.epsl.2011.02.043
  • Savage, PS, Georg, RB, Williams, HM, Burton, KW, Halliday, AN, (2011) 'Silicon isotope fractionation during magmatic differentiation', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 6124-6139 doi: 10.1016/j.gca.2011.07.043
  • Opfergelt, S, Georg, RB, Burton, KW, Guicharnaud, R, Siebert, C, Gislason, SR, Halliday, AN, (2011) 'Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils', Applied Geochemistry. pp.
  • Armytage, RMG, Georg, RB, Williams, HM, Halliday, AN, (2011) 'Silicon isotopes in lunar rocks: Implications for the Moon's formation and the early history of the Earth', Geochimica et Cosmochimica Acta. pp.
  • Armytage, RMG, Georg, RB, Savage, PS, Williams, HM, Halliday, AN, (2011) 'Silicon isotopes in meteorites and planetary core formation', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 3662-3676 doi: 10.1016/j.gca.2011.03.044
  • Savage, PS, Georg, RB, Armytage, RMG, Williams, HM, Halliday, AN, (2010) 'Silicon isotope homogeneity in the mantle', EARTH AND PLANETARY SCIENCE LETTERS. pp. 139-146 doi: 10.1016/j.epsl.2010.03.035
  • Wood, BJ, Halliday, AN, (2010) 'The lead isotopic age of the Earth can be explained by core formation alone.', Nature. pp. 767-770 doi: 10.1038/nature09072
  • Rickli, J, Frank, M, Baker, AR, Aciego, S, de Souza, G, Georg, RB, Halliday, AN, (2010) 'Hafnium and neodymium isotopes in surface waters of the eastern Atlantic Ocean: Implications for sources and inputs of trace metals to the ocean', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 540-557 doi: 10.1016/j.gca.2009.10.006
  • Gutjahr, M, Frank, M, Halliday, AN, Keigwin, LD, (2009) 'Retreat of the Laurentide ice sheet tracked by the isotopic composition of Pb in western North Atlantic seawater during termination 1', EARTH AND PLANETARY SCIENCE LETTERS. pp. 546-555 doi: 10.1016/j.epsl.2009.07.020
  • Leya, I, Schoenbaechler, M, Kraehenbuehl, U, Halliday, AN, (2009) 'NEW TITANIUM ISOTOPE DATA FOR ALLENDE AND EFREMOVKA CAIs', ASTROPHYSICAL JOURNAL. pp. 1118-1126 doi: 10.1088/0004-637X/702/2/1118
  • Kleine, T, Touboul, M, Bourdon, B, Nimmo, F, Mezger, K, Palme, H, Jacobsen, SB, Yin, Q-Z, Halliday, AN, (2009) 'Hf-W chronology of the accretion and early evolution of asteroids and terrestrial planets', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 5150-5188 doi: 10.1016/j.gca.2008.11.047
  • Halliday, AN, Wood, BJ, (2009) 'Geophysics. How did Earth accrete?', Science. pp. 44-45 doi: 10.1126/science.1172587
  • Georg, RB, West, AJ, Basu, AR, Halliday, AN, (2009) 'Silicon fluxes and isotope composition of direct groundwater discharge into the Bay of Bengal and the effect on the global ocean silicon isotope budget', EARTH AND PLANETARY SCIENCE LETTERS. pp. 67-74 doi: 10.1016/j.epsl.2009.03.041
  • Zimmermann, B, Porcelli, D, Frank, M, Andersson, PS, Baskaran, M, Lee, D-C, Halliday, AN, (2009) 'Hafnium isotopes in Arctic Ocean water', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 3218-3233 doi: 10.1016/j.gca.2009.02.028
  • Rickli, J, Frank, M, Halliday, AN, (2009) 'The hafnium-neodymium isotopic composition of Atlantic seawater', EARTH AND PLANETARY SCIENCE LETTERS. pp. 118-127 doi: 10.1016/j.epsl.2009.01.026
  • Nielsen, SG, Mar-Gerrison, S, Gannoun, A, LaRowe, D, Klemm, V, Halliday, AN, Burton, KW, Hein, JR, (2009) 'Thallium isotope evidence for a permanent increase in marine organic carbon export in the early Eocene', EARTH AND PLANETARY SCIENCE LETTERS. pp. 297-307 doi: 10.1016/j.epsl.2008.12.010
  • Zimmermann, B, Porcelli, D, Frank, M, Rickli, J, Lee, D-C, Halliday, AN, (2009) 'The hafnium isotope composition of Pacific Ocean water', GEOCHIMICA ET COSMOCHIMICA ACTA. pp. 91-101 doi: 10.1016/j.gca.2008.09.033
  • Newman, K, Freedman, PA, Williams, J, Belshaw, NS, Halliday, AN, (2009) 'High sensitivity skimmers and non-linear mass dependent fractionation in ICP-MS', JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY. pp. 742-751 doi: 10.1039/b819065h
  • Halliday, AN, (2008) 'A young Moon-forming giant impact at 70-110 million years accompanied by late-stage mixing, core formation and degassing of the Earth.', Philos Trans A Math Phys Eng Sci. pp. 4163-4181 doi: 10.1098/rsta.2008.0209
  • Caro, G, Bourdon, B, Halliday, AN, Quitte, G, (2008) 'Super-chondritic Sm/Nd ratios in Mars, the Earth and the Moon', NATURE. pp. 336-339 doi: 10.1038/nature06760
  • Leya, I, Schoenbaechler, M, Wiechert, U, Kraehenbuehl, U, Halliday, AN, (2008) 'Titanium isotopes and the radial heterogeneity of the solar system', EARTH AND PLANETARY SCIENCE LETTERS. pp. 233-244 doi: 10.1016/j.epsl.2007.10.017
  • Andersen, MB, Stirling, CH, Potter, E-K, Halliday, AN, Blake, SG, McCulloch, MT, Ayling, BF, O'Leary, M, (2008) 'High-precision U-series measurements of more than 500,000 year old fossil corals', EARTH AND PLANETARY SCIENCE LETTERS. pp. 229-245 doi: 10.1016/j.cpsi.2007.10.010
  • Stirling, CH, Andersen, MB, Potter, E-K, Halliday, AN, (2007) 'Low-temperature isotopic fractionation of uranium', EARTH AND PLANETARY SCIENCE LETTERS. pp. 208-225 doi: 10.1016/j.epsl.2007.09.019
  • Markowski, A, Quitte, G, Kleine, T, Halliday, AN, Bizzarro, M, Irving, AJ, (2007) 'Hafnium-tungsten chronometry of angrites and the earliest evolution of planetary objects', EARTH AND PLANETARY SCIENCE LETTERS. pp. 214-229 doi: 10.1016/j.epsl.2007.07.035
  • van de Flierdt, T, Goldstein, SL, Hemming, SR, Roy, M, Frank, M, Halliday, AN, (2007) 'Global neodymium-hafnium isotope systematics - revisited', EARTH AND PLANETARY SCIENCE LETTERS. pp. 432-441 doi: 10.1016/j.epsl.2007.05.003
  • Andersen, MB, Stirling, CH, Porcelli, D, Halliday, AN, Andersson, PS, Baskaran, M, (2007) 'The tracing of riverine U in Arctic seawater with very precise U-234/U-238 measurements', EARTH AND PLANETARY SCIENCE LETTERS. pp. 171-185 doi: 10.1016/j.epsl.2007.04.051
  • Georg, RB, Halliday, AN, Schauble, EA, Reynolds, BC, (2007) 'Silicon in the Earth's core.', Nature. pp. 1102-1106 doi: 10.1038/nature05927

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