Table 1.

Summary of dosimetry, dose equivalent (De) measurements and luminescence quartz ages. The samples (all sand lens) are named according to exposures taken from locations in Figure 4

Sample (n)Depth# (m)Water° (%)238U (Bq kg−1)228Th (Bq kg−1)40K (Bq kg−1)226Ra (Bq kg−1)Dr§ (Gy ka−1)De (Gy)nAge (ka)
PIAS 133.721.5±1.919.3±0.7511.2±8.120.3±0.72.83±0.0375±42327±2
PIAS 453.220.9±3.218.1±0.5503.7±7.119.7±0.42.40±0.0380±52633±3
PIAS 874.376.6±8.693.5±1.4738.5±14.278.4±1.14.61±0.03144±101531±3
  • #Corresponds to the depth of samples below the top of the outcrop.

  • °Corresponds to selected water content chosen for calculation (see text for details).

  • §Represents the conversion factors from activity concentrations to dose rate (from Olley et al. 1996).

  • Note: n is the number of individual aliquots (10 mm diameter stainless steel disc) contributing to De