[1] Liverpool John Moores Univ, Res Ctr Evolutionary Anthropol & Palaeoecol, Sch Nat Sci & Psychol, Liverpool L3 3AF, Merseyside, England
[2] Univ Hull, Funct Morphol & Evolut Unit, Hull York Med Sch, Kingston Upon Hull HU6 7RX, N Humberside, England
[3] British Geol Survey, NERC Isotope Geosci Lab, Keyworth NG12 5GG, Notts, England