The result, t1a = (1.01 ± 0.10) x 10 yr, agrees with the recengeological' half-life of Klein et al., (1991), t1n = (1.03 ± 0.07) x 105 yr, and with the corrected value of Mabuchi et al. We recommend the weighted mean of these three measurements, tla = (1.04 ± 0.05) x i05 yr, as the most probable half-life of 41Ca.
We also discuss the situation of the radioisotopes, 32Si, 44Ti, ?
9Se and 17b Sn, whose half-lives, though still uncertain, are potentially interesting for future AMS studies and other applications.
Although the results in tufa deposits from Egypt are in good agreement with the saturation value of 8x10(-15) predicted by Raisbeck and Yiou (1979), the average Ca-41: Ca-40 ratio of 2x10(-15) (range: 0.6 to 4.2x10(-15) that we measure in modern bone is an order of magnitude lower than than 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 Ca-41: Ca-40 ratio in modern bone make the possibility of dating bones using Ca-41 unlikely.
ABSTRACT: We made preliminary AMS measurements of 41 Ca/Ca ratios in bone and limestone specimens with the Argonne Tandem-Linac Accelerator System (ATLAS).
Discusses some of the new physical dating methods being used by archaeologists and paleoanthropologists to study the material remains of ancient primates.
Describes the quaternary physical dating techniques, advances in radiocarbon dating, and the radiocalcium data method.
Calcium-41 has been suggested as a new tool for radiometric dating in the range of 10(5) to 10(6) years.The concentration of cosmogenic calcium-41 in natural samples of terrestrial origin has now been determined by high-sensitivity accelerator mass spectrometry after pre-enrichment in calcium-41 with an isotope separator.Ratios of calcium-41 to total calcium between 2 x 10(-14) and 3 x 10(-15) were measured for samples of contemporary bovine bone and from limestone deposits.Some prospects for the use of calcium-41 for dating Middle and Late Pleistocene bone and for other geophysical applications are discussed.ABSTRACT: We have performed a new determination of the half-life of 41Ca by measuring the specific activity of an enriched Ca material with known 41Ca abundance.We measured the activity via the 3.3-ke V X-rays emitted in the electron capture decay of 41Ca, and the 41Ca abundance was measured by low-energy mass spectrometry.