Evidence for temporal fluctuations in marine radiocarbon reservoir ages in the Santa Barbara Channel, southern California

Differences in the C-14 ages of closely associated marine shell and carbonized plant material from stratified archaeological deposits on San Miguel Island, California, suggest Holocene (10,000-present) fluctuations in marine C-14 reservoir ages. These fluctuations coincide with delta(18)O and delta(13)C shifts measured in Mytilus californianus shells from the same stratigraphic contexts and general atmospheric/oceanic circulation models for the region. Based on these data we make three primary observations: (1) significant changes appear to have occurred in the radiocarbon reservoir during the Holocene; (2) these fluctuations appear to correlate with regional oceanographic changes; and (3) high resolution C-14 dating of marine shells may require different Delta R values for different periods of time. (C) 1997 Academic Press Limited.