MARINE RESERVOIR EFFECT VALUES FROM SHELL-MIDDENS OF SAN MATIAS GULF, NORTHERN PATAGONIA (ARGENTINA): A 5000-YR RECORD

摘要

Ten marine reservoir effect (R) values were obtained from archaeological shell-middens along the San Matias Gulf, North Patagonian Atlantic coast, Argentina. They were determined by accelerator mass spectrometry (AMS) measurements on marine shell (Mytilidae) and charcoal samples (burned, short-lived plants) derived from a common stratigraphic unit. The R values fluctuate between 205 +/- 48 and 358 +/- 56 C-14 yr BP from ca. 5300 to ca. 700 C-14 yr BP with no obvious temporal trend. Calculated Delta R values fluctuate between +30 +/- 66 and -162 +/- 48 yr during the same time span. Local factors such as restricted connection with the open sea or presence of aged carbonates do not appear to have had an influence on this effect along the gulf coastline. The mean R value obtained (266 +/- 51 yr) constitutes a useful value for correcting ages in shells from abundant archaeological deposits recorded in the area since Middle Holocene times.