PROBLEMS IN RADIOCARBON DATING HUMAN REMAINS FROM ARID COASTAL AREAS - AN EXAMPLE FROM THE CAPE REGION OF BAJA-CALIFORNIA

Three AMS radiocarbon dares on bone collagen from Las Palmas culture h uman skeletons from the cape region of Baja California are analyzed. C arbon derived from both terrestrial and marine sources necessitates co rrecting the radiocarbon ages for reservoir effects. Complicating this , however are (a) the uncertain percentage of carbon of marine origin in the samples and (b) the convergence of the Pacific Ocean and the Gu lf of California, which differ markedly in reservoir values. Computer program CALIB 3.0.3c is used to correct and calibrate the conventional radiocarbon dates in a simulation using varied values for marine carb on and reservoir effects for each sample. This produces substantial va riance in the results and therefore, difficulties for chronological in terpretation. For example, reasonable input values for Delta R and per cent marine carbon yield dales that overlap the first European contact (A.D. 1533), despite the absence of historic documentation of the Las Palmas mortuary complex. Further research on reservoir effects and pa leodiet is needed ill order to interpret radiocarbon determinations oi l cape region human remains. Moreover our findings have serious implic ations for the proper application of radiocarbon dating to samples fro m other regions subject to reservoir effects.