Table 2. Burial depths, grain sizes, water contents, dosimetry data, De and pIRIR ages for the feldspar samples collected from Leang Burung 2.
| Sample | Depth | Grain size (μm) | Water Content (%)a | Gamma dose rate (Gy/ka) | Ext. beta dose rate (Gy/ka) | Int. beta dose rate (Gy/ka)b | Cosmic ray (Gy/ka) | Total dose rate (Gy/ka) | De (Gy)a | Age (ka) | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fading uncorr. | Fading corr. | Fading uncorr. | Fading corr. | |||||||||
| LB2-OSL3 (Layer V) |
160 | 180–212 | 20 ± 5 (18) |
0.782 ± 0.012 | 1.115 ± 0.076 | 0.67 ± 0.15 | 0.08 ± 0.01 | 2.65 ± 0.12 | 103.6 ± 7.9 | 105 ± 5 | 37 ± 4 | 37 ± 4 |
| LB2-OSL4c (Layer II) |
197 | 180–212 | 20 ± 5 (20) |
0.807 ± 0.009 | 1.025 ± 0.09 | 0.67 ± 0.15 | 0.08 ± 0.01 | 2.58 ± 0.13 | 70.8 ± 7.6 | - | 25 ± 3 | - |
| LB2-OSL6 (Layer I) |
248 | 90–180 | 20 ± 5 (20) |
1.216 ± 0.007 | 1.290 ± 0.084 | 0.48 ± 0.13 | 0.07 ± 0.01 | 3.06 ± 0.12 | 47.9 ± 10.1 | 148 ± 38 | 13 ± 3 | 45 ± 10 |
| LB2-OSL10 (Layer I) |
478 | 180–212 | 20 ± 5 (20) |
1.028 ± 0.013 | 1.156 ± 0.074 | 0.67 ± 0.15 | 0.06 ± 0.01 | 2.91 ± 0.12 | 61.0 ± 6.7 | 111 ± 22 | 18 ± 2 | 35 ± 4 |
| LB2-OSL11 (Layer A) |
536 | 90–212 | 20 ± 5 (12) |
1.063 ± 0.010 | 0.915 ± 0.070 | 0.53 ± 0.15 | 0.05 ± 0.01 | 2.57 ± 0.14 | 43.7 ± 8.3 | 195 ± 48 | 14 ± 3 | 72 ± 15 |
| LB2-OSL12 (Layer A) |
532 | 90–212 | 50 ± 10 (54) |
1.275 ± 0.005 | 2.070 ± 0.190 | 0.53 ± 0.15 | 0.05 ± 0.01 | 3.94 ± 0.23 | 110.0 ± 10.1 | 147 ± 21 | 26 ± 3 | 35 ± 4 |
| LB2-OSL13 (Layer B) |
563 | 180–212 | 50 ± 10 (48) |
2.380 ± 0.010 | 2.270 ± 0.230 | 0.67 ± 0.15 | 0.05 ± 0.01 | 5.38 ± 0.25 | 112.1 ± 8.8 | 128 ± 11 | 19 ± 2 | 22 ± 2 |
a The water content of 20 ± 5% was estimated based on field values shown in the brackets.
b Mineralogy analysis of the sediments from Leang Burung 2 suggests that a high percentage of sanidine feldspars in the mineral composition of the sediments from this site. Thus, for the internal dose rate calculation, a K concentration of 10 ± 2% was assumed based on the theoretical K concentration of 10.69% for sanidine [52, 53], while a Rb concentration of 400 ± 100 ppm was assumed [54].
c The equivalent doses were estimated using the sensitivity-corrected pIRIR 290°C signal. All the equivalent doses were corrected for residual doses obtained from bleached aliquots (see text). A fading test was not conducted on LB2-OSL4, and hence the fading-corrected De values are not available for this sample.