Calibration of radiocarbon ages and the interpretation of paleoenvironmental records

Calibration of the radiocarbon timescale of paleoecological records is essential if they are to be explained correctly in terms of their governing ecological or climatological controls, The differences between calendar ages and radiocarbon ages that arise from variations in C-14 production through time can distort the chronologies of individual records and the interpretations based on them, Misleading impressions of synchrony or diachrony of events among multiple records can result, and estimates of the apparent duration of episodes and rates of sedimentation and local population changes can be biased, Displays of the temporal patterns of migration or extinction may also be affected, Spurious correlations may arise between records with radio carbon-controlled chronologies and time series of potential controls that are expressed on a calendar time scale, Support for particular explanations of features in a paleoecological record may vary depending on whether radiocarbon ages are calibrated or not, This situation is illustrated using the eastern Beringian Populus subzone as an example. When the radiocarbon ages that control the timing of the Populus subzone are calibrated, the contemporaneous decrease in ice volume and increase in summer insolation are implicated as the ultimate controls of the occurrence of the subzone. (C) 1995 University of Washington.