Shell survival and time-averaging in nearshore and shelf environments: estimates from the radiocarbon literature

The calibration curves and tables given in this issue of RADIOCARBON form a data base ideally suited for a computerized operation. The program listed below converts a radiocarbon age and its age error os (one standard deviation) into calibrated ages (intercepts with the calibration curve), and ranges of calibrated ages that correspond to the age error. The standard deviation oC in the calibration curve is taken into account using (see Stuiver and Pearson, this issue, for details).

A sea-level curve of the past 35,000 years for the Atlantic continental shelf of the United States is based on more than 80 radiocarbon dates, 15 of which are older than 15,000 years. Materials include shallow-water mollusks, oolites, coralline algae, beachrock, and salt-marsh peat. Sea level 30,000 to 35,000 years ago was near the present one. Subsequent glacier growth lowered sea level to about -130 meters 16,000 years ago. Holocene transgression probably began about 14,000 years ago, and continued rapidly to about 7000 years ago. Dates from most shelves of the world agree with this curve, suggesting that it is approximately the eustatic curve for the period.