Browsing Radiocarbon, Volume 44, Number 1 (2002) by Subjects
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Differences in 14C Age Between Stratigraphically Associated Charcoal and Marine Shell from the Archaic Period Site of Kilometer 4, Southern Peru: Old Wood or Old Water?Consistently large differences occur in the calibrated 14C ages of stratigraphically associated shell and charcoal samples from Kilometer 4, an Archaic Period archaeological site located on the extreme south coast of Peru. A series of nine shell and charcoal samples were collected from a Late Archaic Period (approximately 6000-4000 BP) sector of the site. After calibration, the intercepts of the charcoal dates were approximately 100-750 years older than the paired shell samples. Due to the hyper-arid conditions in this region that promote long-term preservation of organic material, we argue that the older charcoal dates are best explained by people using old wood for fuel during the Middle Holocene. Given this "old wood" problem, marine shell may actually be preferable to wood charcoal for dating archaeological sites in coastal desert environments as in southern Peru and Northern Chile.
Reservoir Corrections for Marine Samples from the South Atlantic Coast, Santa Catarina State, BrazilCoeval shell and charcoal from Santa Catarina State, Brazil, differ systematically in 14C content, indicating a reservoir effect in marine samples. For modern samples (AD 1939-2000) and archeological samples (2500-1595 BP), the mean 14C age difference between marine and atmospheric carbon is 220 +/20 years, the marine carbon being older. For three samples dated AD 1939-1944, a distinct reservoir correction of 510 +/10 years is also observed. The ages of archeological shell samples from Jabuticabeira may be corrected by subtracting 220 years from the apparent 14C ages.