41Ca Concentrations in Modern Bone and Their Implications for Dating

Abstract

ABSTRACT. We have made the first measurements without pre-enrichment of 41Ca in terrestrial rock and bone samples using accelerator mass spectrometry. Although the results in tufa deposits from Egypt are in good agreement with the saturation value of 8 x 1015 predicted by Raisbeck and Yiou (1979), the average 41Ca:40Ca ratio of 2x1015 (range: 0.6 to 4.2x1015) that we measure in modern bone is an order of magnitude lower than that obtained previously by Henning, et al (1987) on a cow bone that was measured using AMS following isotope enrichment. The low value and the variability (more than a factor of seven) of the 4 Ca:40Ca ratio in modern bone make the possibility of dating bones using 41Ca unlikely.

A multi-radionuclide approach for in situ produced terrestrial cosmogenic nuclides: 10Be, 26Al, 36Cl and 41Ca from carbonate rocks

“…All our data is in the range of or lower than the already published one from rock samples, i.e. lower than the six surface samples (3-63 Â 10 À15 ) of Henning et al [23] and Kutschera et al [24] and lower than the surface and strongly shielded sample at 11 m depth (3.4-7.6 Â 10 À15 ) of Middleton et al [25]. As 41 Ca in CaCO 3 is mainly a thermal neutroncapture product, the production (and its calculation) is highly depending on the chemical composition of the sample especially the water-content.…”

Half-life of41Ca

“…AMS measurements of 41Ca in both extraterrestrial and terrestrial materials have been performed, with 41Ca/Ca ratios in the range from 10 -12 to 10 -16. Because of the long half-life of 41 Ca and its presence in bone, it was particularly intriguing to investigate the conditions for radiocalcium dating [5][6][7][8], in analogy to the well-known radiocarbon method. Because of the long half-life of 41 Ca and its presence in bone, it was particularly intriguing to investigate the conditions for radiocalcium dating [5][6][7][8], in analogy to the well-known radiocarbon method.…”

Fluorides or hydrides? 41Ca performance at VERA’s 3-MV AMS facility

“…The use of CaH À 3 allows therefore to measure 41 Ca/Ca isotope ratios down to natural levels, i.e. at 10 À14 and <10 À15 [16,17,11,18]. At the time when 41 Ca was explored as a potential dating tool [1], it was exclusively CaH 2 which was utilized for the AMS measurements.…”