Constraining the age of the Aveline's Hole 9 cranium based on U-TH isotopic analysis of its secondary calcite coating (UBSS Proceedings v.25(3))

Abstract: Sub-samples from two calcite coatings, one adhered to Aveline's Hole 9 (AH9) cranium (housed in Wells and Mendip Museum) and the other expected to be equivalent but of unconfirmed provenance (housed in UBSS Museum), were provided for high-precision mass-spectrometric U-series analysis. The principal aims of the study were to establish (a) whether the UBSS calcite material was originally attached to AH9; (2) the minimum age of AH9 cranium and (3) the original cave setting for calcite deposition. U-Th isochron methods were used to establish the earliest growth of calcite as AD 1824-1955 for both samples. Measured initial 234U/238U activity ratios for the authigenic calcite coatings are indistinguishable and equal to 2.47, which very strongly supports their equivalence. The possibility of using this ratio to fingerprint the source of dripwaters and, hence, the original location is suggested. However, there is insufficient supporting evidence and there remains the likelihood that 'Aveline's Hole 9' is a misnomer.