Alex Halliday

Alex Halliday

Professor of Geochemistry
Tel: +44 (0) 1865 272969

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. 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 five MC-ICPMS instruments.

Alex Halliday CV 2015


  • Egan K., Rickaby R.E.M., Hendry K.R. and Halliday A.N. 2013 Opening the gateways for diatoms primes Earth for Antarctic glaciation, Earth Planet. Sci. Lett. 375, 37-43.
  • Gall, L., Williams H.M., Siebert, C., Halliday A.N., Herrington, R.J. and Hein, J.R. 2013 Nickel isotopic compositions of ferromanganese crusts and the constancy of deep ocean inputs and continental weathering effects over the Cenozoic. Earth Planet. Sci. Lett. 375, 148-155.
  • Georg R.B., West J., Vance D., Newman K. and Halliday A.N. 2013 Is the marine osmium isotope record a probe for CO2 release from sedimentary rocks? Earth Planet. Sci. Lett. 367, 28-38.
  • Halliday, A.N. 2013 The origins of volatiles in the terrestrial planets, Geochim. Cosmochim. Acta 105, 146–171.
  • Opfergelt, S., Burton K.W., Pogge von Strandmann, P.A.E., Gislason S.R. and Halliday A.N. 2013 Riverine silicon isotope variations in glaciated basaltic terrains: Implications for the Si delivery to the ocean over glacial–interglacial intervals, Earth Planet. Sci. Lett. 369–370, 211-219.
  • Prytulak, J., Nielsen, S., Ionov, D.A., Halliday, A.N., Harvey, J., Kelley, K.A., Niu, Y., Peate, D.W., Shimizu, K. and Sims, K.W.W. 2013 The stable vanadium isotope composition of the mantle and mafic lavas, Earth Planet. Sci. Lett., 365, 177–189.
  • Savage, P., Georg R.B., Williams H.M. and Halliday A.N. 2013 The silicon isotope composition of the upper continental crust. Geochim. Cosmochim. Acta 109, 384–399.
  • Savage, P., Georg R.B., Williams H.M. and Halliday A.N. 2013 Silicon isotopes in granulite xenoliths: insights into isotopic fractionation during igneous processes and the composition of the deep continental crust. Earth Planet. Sci. Lett. 365, 221–231.


  • Chambers, J. E. and Halliday A.N. 2014 The origin of the solar system. In: Encyclopaedia of the Solar System 3rd Edition, Chapter 2, 29-54, Elsevier.
  • Gutjahr, M., Frank, M., Lippold, J. and Halliday A.N. 2014 Peak last glacial weathering intensity on the North American continent recorded by the authigenic Hf isotope composition of North Atlantic deep-sea sediments. Quaternary Science Reviews 99, 97-111.
  • Halliday A.N. 2014 The origin and earliest history of the Earth. In: Holland H.D. and Turekian K.K. (eds.) Treatise on Geochemistry, Second Edition, vol. 2, 149-211. Oxford: Elsevier.
  • Nielsen, S., Prytulak, J., Wood, B.J. and Halliday A.N. 2014 Vanadium isotopic difference between the silicate Earth and meteorites. Earth Planet. Sci. Lett. 389, 167–175.
  • Opfergelt S., Burton K.W., Georg R.B., West A.J., Guicharnaud R., Sigfusson B., Siebert C., Gislason S.R., Halliday A.N. 2014 Magnesium retention on the soil exchange complex controlling Mg isotope variations in soils, soil solutions and vegetation in volcanic soils, Iceland.  Geochim. Cosmochim. Acta, 125, 110-130.
  • Savage, P.S., Armytage, R.M.G., Georg R.B. and Halliday A.N. 2014 High temperature silicon isotope geochemistry. Lithos 190/191, 500-519.


  • Abraham, K., Barling, J., Siebert, S., Belshaw, N., Gall, L. and Halliday, A.N. 2015 Determination of mass-dependent variations in tungsten stable isotope compositions of geological reference materials by double-spike and MC-ICPMS J. Anal. At. Spectrom. 30, 2334-2342.
  • Bonnand, P., Williams, H.M., Parkinson, I.J., Wood, B.J. and Halliday, A.N., 2015 Stable chromium isotopic composition of meteorites and metal-silicate experiments: implication for fractionation during core formation. Earth Planet. Sci. Lett., in press.
  • Gannoun, A., Burton, K.W., Barfod, D.N., Schiano, P., Vlastélic, I. and Halliday, A.N. 2015 Resolving mantle and magmatic processes in basalts from the Cameroon volcanic line using the Re–Os isotope system Lithos 224–225, 1–12
  • Halliday A.N., Wood B.J. 2015 The composition and major reservoirs of the Earth around the time of the Moon-Forming Giant Impact. In: Gerald Schubert (editor-in-chief) Treatise on Geophysics, 2nd edition, Oxford: Elsevier; pp. 11-42.
  • Horner, T.J., Williams, H.M, Hein, J.R., Saito, M.A., Burton, K.W., Halliday, A.N. and Nielsen, S.G. 2015 Persistence of deeply sourced iron in the Pacific Ocean, PNAS 112, 1292-1297.
  • Larner, F., Woodley, L.N., Shoushad, S., Moyese, A., Humphreys-Williams, E., Strekopytov, S., Halliday, A.N., Rehkämper, M. and Coombes, C.R. 2015 Zinc isotopic compositions of breast cancer tissue, Metallomics 7, 107-112.
  • Siebert, C., Pett-Ridge, J., Opfergelt, S., Guicharnaud R.A., Halliday, A.N. and Burton, K. 2015 Molybdenum isotope fractionation in soils: influence of redox, organic matter, and atmospheric inputs, Geochim. Cosmochim. Acta 162, 1-24.
  • Stirling C.H., Andersen M.B., Warthmann, R. and Halliday, A.N. 2015 Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction. Geochim. Cosmochim. Acta 163, 200-218.
  • Ventura, G.T., Gall, L., Siebert, C., Prytulak, J., Szatmari, P., Hürlimann, M. and Halliday, A.N. 2015 The stable isotope composition of vanadium, nickel, and molybdenum in crude oils, Applied Geochem., 59, 104-117.
  • Yang, J., Siebert, C., Barling, J., Savage, P., Liang, Y-H. and Halliday, A.N. 2015 Absence of molybdenum isotope fractionation during magmatic differentiation at Hekla volcano, Iceland. Geochim. Cosmochim. Acta, 162, 126-136.