Amino acid racemisation dating
Wehmiller (1977) showed that the shell radiocarbon and racemization data were consistent with shallow ground thermal effects.
Unfortunately, dating of these deposits can be problematic (e.g. Radiocarbon dating is usually applied to develop chronological frameworks for shell midden deposits.Masters and Bada (1977, 1978) compared the extent of isoleucine epimerization in radiocarbon dated shells and found distinct divergences.They attributed these to both inaccuracies in radiocarbon dating of carbonate and the isoleucine method on shell.However, earlier midden deposits are present in some areas of the world, often in deep cave sequences but also in some open-air locations.
Middens from the Last Interglacial (Eemian) and before have been reported in Africa (e.g.The present work involves the application of recently introduced methodologies of AAR dating to shell material (Sykes et al., 1995; Kaufman and Manley, 1998; Penkman et al., 2008), which have been successfully used to date Quaternary terrestrial and marine sediments in the British Isles (Parfitt et al., 2005; Penkman et al., 2007; Davies et al., 2009).