Chronological Assessment

The contributor provides each site with a minimum of one age scheme. Ages are based on radiocarbon data, sometimes in combination with other well dated stratigraphic markers (e.g., volcanic ash). If a site has more than a single age scheme, the contributor will define one as the preferred chronology. An independent means for assessing the quality of any particular dating scheme is also important. The quality is determined by a combination of how well a target time is confined by radiocarbon dates (ranking dating accuracy) and by the proximity of a sample to the specified time (ranking sampling accuracy). We independently rank dating accuracy and sampling accuracy on scales of one to ten, which together provides an overall assessment of the chronology. For example, a site may have two radiocarbon dates that closely bracket a targeted mapping date, in which case the site would receive high rank (e.g., one or two) indicating good dating control. However, that same site may have a broad sampling interval and no primary data fall at or near the target date. This poor sampling of the desired time result in a low rank (e.g. nine or ten) for sampling accuracy.

Assessments for: 6000 yr. B.P. | 18,000 yr. B.P.