Values used to calculate Annual dose rate from IRA trench_ Uncertainties are based on the propagation, in quadrature, of errors associated with individual errors for all measured quantities_
| Sample | Water (%) | Depth (m) | K (%) | U (ppm) | Th (ppm) | Cosmic (Gy/ka) | Dose rate (mGy/yr) |
|---|---|---|---|---|---|---|---|
| Ira.I | 5.25 | 1.39 | 1.07 | 1.12 | 5.29 | 0.16 ± 0.14 | 1.77 ± 0.14 |
| Ira.IV | 9.66 | 0.6 | 1.33 | 1.65 | 6.30 | 0.18 ± 0.14 | 2.14 ± 0.15 |
| Ira.V | 6.6 | 1.22 | 1.11 | 1.34 | 4.99 | 0.16 ± 0.14 | 1.82 ± 0.14 |
| Ira.VIII | 8.46 | 2.04 | 0.77 | 1.69 | 4.65 | 0.14 ± 0.14 | 1.52 ± 0.14 |
Generalized single aliquot regenerated sequence and outline of the steps involved in the SAR method_ *Observed Lx and Tx are derived from the initial IRSL signal (2 s) minus a background estimated from the last part of the stimulation curve_ Corrected natural signal N = L0/T0; Corrected regenerated signal Rx = Lx/Tx (x = 1–5)_ Note that in step 2, the sample has been heated to the pre-heat temperature using TL and held at that temperature for 10 s_
| Step | Treatment 1 | *Ob |
|---|---|---|
| 1 | Give dose | – |
| 2 | Pre-heat (TL 200–300°C) | – |
| 3 | Stimulation (at 120°C) | LX |
| 4 | Give test dose | – |
| 5 | Cut-heat (TL 120–260°C) | – |
| 6 | Stimulation (at 125°C) | TX |
| 7 | Return to 1 | – |
Des used to calculate luminescence ages employing three different statistical methods, Central age model (CAM), Finite mixture modelling (FMM) and Minimum age model (MAM)_
| Sample ID | De (Gy) | Age (ka) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CAM | ± | FMM | ± | MAM | ± | CAM | ± | FMM | ± | MAM | ± | |
| Ira.I | 11.4 | 1.3 | 6.4 | 0.9 | ||||||||
| Ira.IV | 123.9 | 11.0 | 13.0 | 0.9 | 7.5 | 0.6 | 58.0 | 6.5 | 6.1 | 0.6 | 3.5 | 0.3 |
| Ira.V | 13.3 | 2.0 | 7.3 | 1.3 | ||||||||
| Ira.VIII | 53.3 | 7.9 | 32.7 | 0.9 | 20.0 | 6.3 | 35.0 | 6.1 | 21.5 | 2.2 | 13.1 | 4.3 |