Radiocarbon calibration - past, present and future

Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15600 years ago. Since 1998, a wealth of AMS measurements became available, covering the complete C-14 dating range. No calibration curve can presently be recommended for the older part of the dating range until discrepancies are resolved. (C) 2004 Elsevier B.V. All rights reserved.