Shell Chione

Radiocarbon Dating of Amino Acids Extracted from Chione Shell. We attempted to resolve the question of which dating method produced more accurate shell dates by submitting amino acids extracted from Chione shell for a radiocarbon analysis (20). Because of the possibility of exchange with groundwater carbonates, the inorganic carbon in mollusc shell can be contaminated easily. We reasoned that the carbon in the amino acids would provide a more reliable age estimate than the carbon-... 

Although the first demonstration that amino acid racemization took place in fossils used mollusc shells (23), the application of this reaction in dating these materials has been extensively investigated only recently (19,20). Work on Mercenaria (19), Chione (20), and other species (24) has tested the application of racemization dating to fossil mollusc shells from geological contexts and Indian shell middens. These and other studies have shown that there are problems with amino acid racemization dating of carbonaceous fossils which are not encountered with bone. Reversible first-order racemization kinetics which are observed in bone... 

Racemization Dating of Chione from Indian Middens. The prehistoric inhabitants of coastal southern California left abundant kitchen midden deposits marking their living sites. Mollusc shells are the major constituents found in these middens. We attempted to deduce racemization dates for shell from six archaeological sites along the coast of southern California (20). All of these sites had carbon-14 dates on shell carbonate available for comparison. 

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