Staff and Postgraduate Students
Dr Chris Dale
BSc (Edinburgh) 2000
PhD (Open University) 2005
2005-present NERC Postdoctoral researcher, Department of Earth Sciences, Durham University
Dale’s work focuses principally on using the Re-Os system and highly siderophile elements (HSE, including the platinum-group elements) to understand a range of topics from mantle recycling and the origin of mantle-derived magmas to the accretion and differentiation of planetary bodies.
Recent work measuring HSE in meteoritic fragments of asteroids, published in Science, found that late accretion of primitive material to planetary bodies, after their metallic cores had formed, occurred on all known bodies, irrespective of their size and timing of accretion. Furthermore, the primary control on the amount of HSE delivered to the silicate mantles of each planetary body, including Earth, the Moon, Mars and the asteroid 4-Vesta appears to have been its oxygen fugacity. By inference, oxygen fugacity must have increased from initially reduced conditions very early in Earth's history.
Early work investigated whole-rock and mineral scale geochemical modifications to oceanic crust during subduction-related metamorphism, with particular emphasis on the Re-Os isotope system and the HSE element budget. This work found that the proportions of oceanic crust in the mantle sources of some OIB could be lower than previously envisaged.
Subsequently, Dale has conducted studies of HSE and Re-Os in oceanic basalts from the Philippine Sea Plate and picrites from the Etendeka and North Atlantic Igneous Province. The latter indicated that high 3He/4He mantle must be primitive or typical convecting mantle and precluded ancient melt depletion as a means of explaining the high3He/4He signature. It also provided an additional estimate for the typical Os isotope composition of convecting mantle.
On-going work includes a comprehensive isotope study of primitive lavas from the end-member fluid-dominated Tongan arc - including lithophile isotope systems (Sr, Nd, Pb, Hf), volatile isotopes (O, H) and Os isotopes and PGE abundances. The findings from Os and HSE are currently in press (GCA) where we recognise, for the first time, the importance of Cr-spinel and associated platinum-group minerals in controlling HSE fractionation during subduction zone flux-melting, important for understanding mantle Os isotope evolution and the formation of Cu-Au-PGE deposits in arc settings.
His chemical and analytical experience includes the analysis of HSE and Re-Os by Carius tube digestion, HP-asher digestion and HF-HBr dissolution/bromine extraction. The latter has been used for sub-0.1pg Os analyses of gabbroic silicate mineral separates. In addition, he has utilised Sr, Nd, Hf, Pb and Li isotopes as well as analysing trace elements by both solution ICP-MS and in situ laser ablation-ICP-MS.
Currently, Dale is utilising laser ablation ICP-MS for the rapid determination of Os isotopes in ophiolite-derived PGE alloys, as a means of assessing global Os isotope heterogeneity in the mantle and investigating possible episodes of mantle depletion which may be linked to pulses of continental growth. Further work includes investigations of early Earth differentiation processes.
- Dale CW, DG Pearson, GM Nowell, & SW Parman, T Oberthür, KN Malitch (2010), Os isotopes in Witwatersrand platinum-group alloys: Implications for ancient mantle melting events and the timing of gold formation, Goldschmidt Conference. Knoxville, Geochimica et Cosmochimica acta, A203.
- Dale, C.W., Macpherson C.G., Boyce A.J., Nowell G.M., Pearson, D.G. & Arculus, R.J. (2008), Assessing mantle and subduction contributions to Tongan arc magmatism with H, O and lithophile isotopes, IAVCEI General Assembly. Reykjavik, Iceland.
- Dale, C.W., MacPherson, C.G., Pearson, D.G., Nowell, G.M., Hammond, S.J. & Arculus, R.J. (2007), Hf, Sr, Nd and Pb isotopes in primitive Tongan lavas: Constraining mobility in slab fluids, 71:15: Goldschmidt Conference. Geochimica et Cosmochimica Acta, A198.
Journal papers: academic
- Bentley, R.A., Bickle, P. Fibiger, L., Nowell, G.M., Dale, C.W., Hedges, R.E.M., Hamilton, J., Wahl, J., Francken, M., Grupe, G., Lenneis, E., Teschler-Nicola, M., Arbogast, R.-M., Hofmann, D. & Whittle, A. (2012). Community differentiation and kinship among Europe's first farmers. Proceedings of the National Academy of Sciences, USA 109(24): 9326-9330.
- Dale, C.W., Macpherson, C.G., Pearson, D.G., Hammond, S.J. & Arculus, R.J. (2012). Inter-element fractionation of highly siderophile elements in the Tonga Arc due to flux melting of a depleted source. Geochimica et Cosmochimica Acta 89: 202-225.
- Dale, C.W., Burton, K.W., Greenwood, R.C., Gannoun, A., Wade, J., Wood, B.J. & Pearson, D.G. (2012). Late accretion on the earliest planetesimals revealed by the highly siderophile elements. Science 336(6077): 72-75.
- Caulfield, J., Turner, S., Arculus, R.J., Dale, C.W., Jenner, F., Pearce, J., Macpherson, C.G. & Handley, H. (2012). Mantle flow, volatiles, slab-surface temperatures and melting dynamics in the north Tonga arc – Lau back-arc basin. Journal of Geophysical Research 117: B11209.
- Gibson, S.A., Geist, D.G., Day, J.A. & Dale, C.W. (2012). Short wavelength heterogeneity in the Galápagos plume: Evidence from compositionally diverse basalts on Isla Santiago. Geochemistry Geophysics Geosystems 13: Q09007.
- Ishikawa, A., Pearson, D.G. & Dale, C.W. (2011). Ancient Os isotope signatures from the Ontong Java Plateau lithosphere: Tracing lithospheric accretion history. Earth and Planetary Science Letters 301(1-2): 159-170.
- Harvey, J., Dale, C.W., Gannoun, A. & Burton, K.W. (2011). Osmium mass balance in peridotite and the effects of mantle-derived sulphides on basalt petrogenesis. Geochimica et Cosmochimica Acta 75(19): 5574–5596.
- Wittig N., Webb M., Pearson D.G., Dale C.W., Ottley C.J., Hutchison M., Jensen S.M. & Luguet A. (2010). Formation of the North Atlantic Craton: Timing and mechanisms constrained from Re-Os isotope and PGE data of peridotite xenoliths from SW Greenland. Chemical Geology 276(3-4): 166-187.
- Dale, C.W., Burton, K.W., Pearson, D.G., Gannoun, A., Alard, O., Argles, T.W. & Parkinson, I.J. (2009). Highly siderophile element behaviour accompanying subduction of oceanic crust: Whole rock and mineral-scale insights from a high-pressure terrain. Geochimica et Cosmochimica Acta 73: 1394-1416.
- Dale, C.W., Pearson, D.G., Starkey, N.A. Stuart, F.M., Ellam, R.M., Larsen, L.M., Fitton, J.G. & Macpherson, C.G. (2009). Osmium isotopes in Baffin Island and West Greenland picrites: Implications for the 187Os/188Os composition of the convecting mantle and the nature of high 3He/4He mantle. Earth and Planetary Science Letters 278(3-4): 267-277.
- Dale, C.W., Luguet, A., Macpherson, C.G., Pearson, D.G. & Hickey-Vargas, R. (2008). Extreme platinum-group element fractionation and variable Os isotope compositions in Philippine Sea Plate basalts: Tracing mantle source heterogeneity. Chemical Geology. Spec. publ 248(3-4): 213-238.
- Dale, C.W., Gannoun, A., Burton, K.W., Argles, T.W. & Parkinson, I.J. (2007). Rhenium-osmium isotope and elemental behaviour during subduction of oceanic crust and the implications for mantle recycling. Earth and Planetary Science Letters 253: 211-225.