Fig. 1
Study area and the location of the section ZZGD in BJD. The section ZZGD is in the lowland of the megadunes and beside the modern lake Zongzhegedan. The section is higher than the modern lake surface about 7 m.
Fig. 2
The ZZGD section and the typical deposits in the section. The red dots indicated the optical dating sampling points.
Table 1
The OSL, pIRIR(50,290) and MET pIRIR dating protocols.
| Step | OSL protocol (Wintle and Murray, 2006) | pIRIR(50,290) protocol (Thiel et al., 2011) | MET-pIRIR protocol (Li et al., 2014) |
|---|---|---|---|
| 1 | Give regenerative dose, Dia | Give regenerative dose, Dia | Give regenerative dose, Dia |
| 2 | Preheat at 240°C for 10 s | Preheat at 320°C for 60 s | Preheat at 320°C for 60 s |
| 3 | OSL, 80 s at 125°C | IRSL, 200 s at 50°C | IRSL, 200 s at 50°C |
| 4 | Give test dose, Dt | IRIR, 200 s at 290°C | IRIR, 200 s at 100°C |
| 5 | Preheat at 220°C for 0 s | Give test dose, Dt | IRIR, 200 s at 150°C |
| 6 | OSL, 80 s at 125°C | Preheat at 320°C for 60 s | IRIR, 200 s at 200°C |
| 7 | OSL, 40 s bleaching at 280°C | IRSL, 200 s at 50°C | IRIR, 200 s at 250°C |
| 8 | Return to step 1 | IRIR, 200 s at 290°C | IRIR, 200 s at 300°C |
| 9 | IRSL, 100 s bleaching at 325°C | Give test dose, Dt | |
| 10 | Return to step 1 | Preheat at 320°C for 60 s | |
| 11 | IRSL, 200 s at 50°C | ||
| 12 | IRIR, 200 s at 100°C | ||
| 13 | IRIR, 200 s at 150°C | ||
| 14 | IRIR, 200 s at 200°C | ||
| 15 | IRIR, 200 s at 250°C | ||
| 16 | IRIR, 200 s at 300°C | ||
| 17 | IRSL, 100 s bleaching at 325°C | ||
| 18 | Return to step 1 |
Table 2
The results of the OSL dating using quartz and IRSL dating using K-feldspar. In the results of the IRSL dating, the upper line is the results by using pIR50IR290, and the lower line is the results using the MET pIRIR procedure.
| Sample name | Depth (m) | water Content (%) | K (%) | U (ppm) | Th (ppm) | OSL (Quartz) | IRSL (K-feldspar) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Dose rate (Gy/ka) | De (Gy) | Age (ka) | Dose rate (Gy/ka) | De (Gy) | Age (ka) | ||||||
| ZZGD-45 2015-67 | 0.45 | 10.0 | 1.63±0.05 | 4.92±0.14 | 6.76±0.22 | 3.26±0.25 | 112.32±9.76 | 34.5±4.0 | 3.79±0.26 | 216.22±8.98 229.14±2.78 | 56.9±4.6 60.3±4.3 |
| ZZGD-120 2015-66 | 1.20 | 10. 0 | 1.62±0.05 | 3.46±0.11 | 6.66±0.21 | 2.80±0.22 | 138.97±8.94 | 49.5±5.0 | 3.33±0.23 | 210.94±11.07 224.69±5.58 | 63.3±5.5 67.4±4.9 |
| ZZGD-165 2015-70 | 1.65 | 10.0 | 1.63±0.05 | 3.42±0.11 | 8.28±0.25 | 2.89±0.23 | 135.36±3.84 | 46.7±3.9 | 3.42±0.24 | 213.69±5.01 224.45±4.36 | 62.3±4.5 65.5±4.7 |
| ZZGD-195 2015-71 | 1.95 | 10. 0 | 1.77±0.06 | 2.05±0.09 | 7.03±0.22 | 2.63±0.21 | 139.84±9.90 | 53.1±5.6 | 3.16±0.21 | 229.93±11.99 230.98±9.10 | 72.7±6.2 73.6±5.8 |
| ZZGD-290 2015-72 | 2.90 | 10.0 | 1.83±0.06 | 2.03±0.08 | 8.03±0.24 | 2.73±0.21 | 170.91±12.94 | 62.7±6.8 | 3.25±0.22 | 245.09±16.54 235.01±8.97 | 75.34±7.3 72.3±5.7 |
| ZZGD-300 2015-68 | 3.00 | 10.0 | 1.79±0.06 | 3.11±0.11 | 7.50±0.23 | 2.91±0.23 | 190.86±7.63 | 65.46±5.8 | 3.42±0.23 | 261.41±12.55 290.15±4.86 | 76.5±6.4 84.9±6.1 |
| ZZGD-365 2015-69 | 3.65 | 10. 0 | 1.76±0.06 | 2.03±0.09 | 6.95±0.22 | 2.60±0.20 | 215.68±12.63 | 82.9±8.2 | 3.10±0.21 | 250.23±4.99 287.22±8.98 | 80.6±5.7 92.5±6.9 |
Fig. 3
Radial plot of the De values of 6 lacustrine sediments in MET-pIRIR protocol.
Fig. 4
Pulse-annealing curves for quartz aliquots from four samples. The remnant OSL signals are versus the annealing temperature.
Fig. 5
The optical dating results of studied section ZZGD and the grain size analysis results. Over 80% of the sediments grains in the section are coarse grain larger than 63 μm as the bottom aeolian sand layer.