Accelerator Radiocarbon Dates on Charcoal, Shell, and Human Bone from the Del Mar Site, California

Abstract

Accelerator radiocarbon dates on shell, charcoal, and human bone samples are an indication that human activity at the Del Mar site dates to 5000 B.P. and possibly from 7000 B.P. The shell and charcoal fragments were dislocated stratigraphically by extensive bioturbation and provide evidence that accelerator dates on extremely small samples should be used with caution. Certain depositional environments will require multiple dating within a site because single-sample dating will not yield definitive ages. Dating of individual amino acids from the Del Mar sphenoid yielded an average age of 4900 ± 40 B.P. and conclusively establishes the age for the Del Mar skull. The previously dated tibia was found to be contaminated with exogenous amino acids, thereby making its age uncertain.