Coarse versus fine-grain quartz optical dating of the sediments related to the 1985 Ms7.1 Wuqia earthquake, northeastern margin of the Pamir salient, China

Huili Yang; Jie Chen; Naomi Porat; Tao Li; Wenqiao Li; Weipeng Xiao

doi:10.1515/geochr-2015-0075

Figures & Tables

Aster image showing regional tectonic structure, the 1985 Wuqia earthquake surface rupture and trench location. Modified from Li et al. (2012).

Location of the modern sample LED11-7 (Left); Trench wall showing the location of samples LED11-1, 11-2 and 11-6 (Right).

Luminescence characteristics. a – Quartz purity IR check; b – Dose recovery as a function of preheat temperature for coarse grains quartz; c – OSL decay curves for single quartz grains from sample LED11-1, the inset shows a corresponding dose response curve (DRC), the red point is recycling point; d – A histogram of dose recovery ratios for single quartz grains using a 10 s preheat at 260°C for and a 220°C cutheat.

a – Sensitivity-corrected multiple aliquot regenerative-dose growth curve (SMAR) of sample LED11-1; b – OSL decay curves of sample LED11-1; c – A SAR growth curve; d – Coarse grain quartz small aliquot standardized growth curve (SA-DRC). The red diamonds are sample-specific and were projected on the SA-DRC.

Radial plots and KDE plots from single grains (SG) and small aliquot standardised growth curve (SA-SGC) for samples LED11-1, LED11-2 and LED11-6. Grey bands on radial plots show the samples’ De values with 2-sigma error (Table 2). Only KDE plots are shown for the sample LED11-7.

Dose rate results for the samples_

Sample No.	Depth (m)	U (ppm)	Th (ppm)	K (%)	Water content Water contents were estimated at 5 ± 5% or 2 ± 2% (%)	Dose rate (Gy/ka)
Sample No.	Depth (m)	U (ppm)	Th (ppm)	K (%)
						CQ	FQ
LED11-1	2.4	1.65	5.3	1.37	5 ± 5	2.1 ± 0.1	2.9 ± 0.2

LED11-2	2.8	1.74	4.84	1.15	5 ± 5	2.0 ± 0.1	2.6 ± 0.1

LED11-6	0.6	1.96	7.75	1.49	2 ± 2	2.7 ± 0.2	3.4 ± 0.2

LED11-7	0.2	1.35	4.67	1.2	2 ± 2	2.1 ± 0.1	2.5 ± 0.1

De values of single grains, small aliquot SA-SGC and fine grains for the samples shown on Fig 2_

Sample No.	Single grains					Small aliquot SA-SGC					Fine grains

	n/N n represents the number of accepted single grains or small aliquots that passed the SAR rejection criteria and used for D_e determination, N represents total number of grains or aliquots measured;	P Proportion (%) of the grains or aliquots that have a detectable OSL signal; (%)	OD over-dispersion; (%)	D_e D_e obtained using the minimum age model. (Gy)	Age (ka)	n/N n represents the number of accepted single grains or small aliquots that passed the SAR rejection criteria and used for D_e determination, N represents total number of grains or aliquots measured;	P Proportion (%) of the grains or aliquots that have a detectable OSL signal; (%)	OD over-dispersion; (%)	D_e D_e obtained using the minimum age model. (Gy)	Age (ka)	D_e (Gy)	Age (ka)
LED11-1	158/4800	3.3	45	14.3−1.7+1.9$14.3_{-1.7}^{+1.9} $	6.7−0.9+1.0$6.7_{-0.9}^{+1.0} $	43/78	55	36	14.3−3.0+3.3$14.3_{-3.0}^{+3.3} $	6.7−1.5+1.6$6.7_{-1.5}^{+1.6} $	65.7 ± 5.4	22.9 ± 1.9

LED11-2	55/2300	2.4	62	9.6−1.9+2.5$9.6_{-1.9}^{+2.5} $	4.9−1.0+1.3$4.9_{-1.0}^{+1.3} $	63/142	44	59	9.8−1.8+3.0$9.8_{-1.8}^{+3.0} $	5.0−1.0+1.6$5.0_{-1.0}^{+1.6} $	157.6 ± 14.3	60.5 ± 5.4

LED11-6	55/3700	1.5	45	5.2−1.0+1.4$5.2_{-1.0}^{+1.4} $	2.0−0.4+0.5$2.0_{-0.4}^{+0.5} $	52/144	40	33	5.4−0.5+1.1$5.4_{-0.5}^{+1.1} $	2.0−0.2+0.6$2.0_{-0.2}^{+0.6} $	66.8 ± 3.1	19.5 ± 0.9

LED11-7	53/1800	2.9	80	0.2−0.1+0.2$0.2_{-0.1}^{+0.2} $	0.1−0.05+0.1$0.1_{-0.05}^{+0.1} $	42/88	47	59	0.3−0.2+0.3$0.3_{-0.2}^{+0.3} $	0.15−0.1+0.15$0.15_{-0.1}^{+0.15} $	7.0 ± 0.3	2.8 ± 0.1

Coarse versus fine-grain quartz optical dating of the sediments related to the 1985 Ms7.1 Wuqia earthquake, northeastern margin of the Pamir salient, China

Figures & Tables

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Dose rate results for the samples_

De values of single grains, small aliquot SA-SGC and fine grains for the samples shown on Fig 2_

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