This value is very similar with the value, 0.052, for calcite speleothem obtained by Lyons and Brennan (1991), and in the same order with those for mollusk shells, 0.07 to 0.10 (Grün, 1985; Grün and Katzenberger, 1994) and with those for corals, 0.05 to 0.15 (Ikeya and Ohmura, 1983; Radtke ., 1992; Malmberg and Radtke, 2000).However, further works would still be needed, firstly, to confirm that the k-value for the present young natural sample, HPD#1621R07, is reproducible in other natural samples.The alpha effectiveness of the SOA natural barite sample was extracted from a hydrothermal deposit taken from the sea-floor at the Hatoma Knoll, and Iheya North Knoll of Okinawa Trough as listed in Table 1 where they were dated by ESR to be 1480 to 6300 years.
Barite crystals are formed when submarine hydrothermal fluid containing Ba is mixed with sea water containing sulfate anions.
The efficiency value to He ion dose in the synthetic sample is consistent with the one in the young natural sample as shown in Table 1 while the value to gamma ray dose is higher in the synthetic than in the natural young sample, making the k-value lower.
This efficiency value, the saturated intensity value, and the dose value at which saturation starts (typically indicated by D) in the dose response would directly be related with the formation mechanism.
This value is 19% higher than the previously reported value of 0.043 ± 0.018 (Toyoda ., 2012).
With this value, the ESR ages will typically become about 10% younger than the ones with the old k-values where currently, this difference will not affect the geological interpretations.