Radiocarbon ages measured on replicated samples, each sample containing a small (3-30) number of individual foraminifera picked from a discrete depth of a single sediment core. These data come from five sediment cores and were used to estimate the age-heterogeneity of material at discrete depths in the five cores. Radiocarbon ages made on larger "bulk" samples of foraminifera, or mean radiocarbon ages of multiple smaller samples. These were used to estimate sediment accumulation rates at the same four sediment cores.