Radiocarbon Dating

Hated dart points, as revealed through CT scanning, and their calibrated AMS radiocarbon date ranges. The older specimen at left as been tentatively classified as type Hueco, the other three as type Carlsbad. Click on each point to view radiocarbon data report.

The intact condition and excellent preservation of the hafted dart points from Ceremonial Cave made them exceptional candidates for radiocarbon dating. Small samples were removed from the wood foreshaft on three specimens and the wrapping material on one and submitted to Beta Analytic Inc. for AMS radiocarbon dating.

Two samples received the standard pretreatment and analysis and two received a solvent extraction to remove any potential preservative/pesticide contamination. No evidence for contamination was found. For those samples not large enough for 13C/12C ratio measurement, a ratio including both natural and laboratory effects was measured during the 14C detection to derive a conventional radiocarbon age suitable for applicable calendar calibration.

For each of the sampled specimens, both conventional and calibrated dates were calculated and results plotted on a graph. These findings place the manufacture of the darts within a circa 1900-year period ranging from 1690 B.C. to A.D. 220. CT scans reveal that the chipped-stone dart points are expanding stem varieties tentatively classified as type Carlsbad or Hueco. The three classified as Carlsbad are dated to 400 B.C. to A.D. 220 whereas the Hueco specimen is significantly older at 1690-1530 B.C. In the image above, the results for each specimen can be viewed by clicking on each dartpoint.

Additional samples from other perishable artifacts from Ceremonial Cave have been submitted for radiocarbon dating and results will be added to this exhibit as findings become available.

 

Small wood fragments in foil, being readied for analysis. AMS dating can be performed on much smaller samples than required for standard radiocarbon methods. Photo by Phil Geib.