The Bleaching of Different K-Feldspar pIRIR Signals of Source Materials of Lacustrine Sediment – A Case Study from Bosten Lake Basin in Arid Central Asia

He Yang; Guoqiang Li; Ming Jin; Haixia Zhang; Xiaoyan Wang; Christopher Oldknow; Zhong Wang; Xin Huang

doi:10.2478/geochr-2020-0013

Figures & Tables

a) location map indicating position of Bosten Lake located on the southeastern side of the Yanqi basin on the southern slope of the Tian Shan Mountain; b) indicates the distribution of different modern depositional environments around the Bosten Lake Basin which were sampled. Four eolian sand samples (BST16S-1, BST16S-2, BST16S-3, and BST16S-14) were collected from the widespread sand dune field around the lake. Six samples BST16S-4, BST16S-5, BST16S-6, BST16S-7, BST16S-8 and BST16S-9 were collected from the over flooding deposit at different points of Kaidu River channel. Three samples BST16S-10, BST16S-11 and BST16S-12 were collected from the surface of the pluvial fan down the Elbin-Alagou Mountains. The red cycle with BST12B besides is the location of drill core BST12B from Li et al. (2016).

Locations of modern analogue samples collected from different potential sources of lake sediment at Bosten Lake Basin.

a) b) c) show the dose recovery test results from sample BST16S-1. a is the measured dose/given (M/G) dose; b) and c) show the recycling ratios and recuperation values.

Luminescence characteristics of K-feldspar pIRIR signal for samples: a), b) and c) show representative decay and growth curves from the pIR50IR170, IR50, pIR50IR290, IR50 and pIR200IR290, IR200 signals for K-feldspar sample BST16S-5. d), e) and f) show the recycling ratios and recuperation values of all aliquots for the pIR50IR170, pIR50IR290 and pIR200IR290 De measurements for all samples, respectively.

The distribution of De (a) and age (b) values obtained using different pIRIR signals (pIR50IR170 De, pIR50IR290 De and pIR200IR290).

a) and b) pIRIR ages from eolian and river sediments plotted as a function of distance from sampling sites from Bosten Lake, respectively.

Plots of the residual doses of eolian samples (a), fluvial samples (b) and pluvial samples (c) obtained using different pIRIR signals after 112 h sunlight bleaching as a function of the associated De values.

a), b), c) and d) show the hard-to-bleach dose values for eolian, fluvial, and pluvial and lacustrine samples, respectively. pIR50IR170 residual dose of loess (red cycles) in a) and pIR50IR290 residual dose of lacustrine samples (square and triangle) in d) are cited from Li et al. (2015b) and Li et al. (2016), respectively.

Summary of the residual dose after 112 h bleaching under sunlight for all samples from Bosten lake Basin_

Sample No.	Residual dose (112 h bleaching)
Sample No.	IR₅₀ (Gy)	pIR₅₀IR₁₇₀ (Gy)	IR₅₀ (Gy)	pIR₅₀IR₂₉₀ (Gy)	IR₂₀₀ (Gy)	pIR₂₀₀IR₂₉₀ (Gy)
BST16S-1	0.53 ± 0.01	0.10 ± 0.005	0.34 ± 0.01	2.01 ± 0.05	0.76 ± 0.02	2.11 ± 0.08
BST16S-2	0.05 ± 0.001	0.33 ± 0.01	0.32 ± 0.01	2.06 ± 0.05	0.75 ± 0.02	2.26 ± 0.09
BST16S-3	0.07 ± 0.002	0.15 ± 0.005	0.32 ± 0.01	1.80 ± 0.05	0.78 ± 0.02	2.48 ± 0.11
BST16S-4	0.08 ± 0.002	1.02 ± 0.02	0.80 ± 0.02	4.74 ± 0.12	1.82 ± 0.04	6.01 ± 0.22
BST16S-5	0.06 ± 0.002	0.62 ± 0.02	0.65 ± 0.02	3.43 ± 0.09	1.57 ± 0.04	5.00 ± 0.19
BST16S-6	0.39 ± 0.01	1.02 ± 0.02	1.00 ± 0.03	4.93 ± 0.13	1.99 ± 0.04	6.85 ± 0.27
BST16S-7	0.26 ± 0.01	1.10 ± 0.03	0.95 ± 0.02	6.00 ± 0.17	1.66 ± 0.04	5.48 ± 0.18
BST16S-8	0.30 ± 0.01	1.34 ± 0.03	0.89 ± 0.02	5.11 ± 0.14	2.25 ± 0.05	7.53 ± 0.28
BST16S-9	0.42 ± 0.01	1.58 ± 0.04	1.04 ± 0.03	5.19 ± 0.14	2.21 ± 0.05	7.21 ± 0.26
BST16S-10	0.50 ± 0.01	3.47 ± 0.08	1.57 ± 0.04	10.69 ± 0.29	3.50 ± 0.08	14.32 ± 0.51
BST16S-11	0.56 ± 0.01	3.91 ± 0.09	1.77 ± 0.04	11.35 ± 0.29	3.82 ± 0.08	15.94 ± 0.55
BST16S-12	0.89 ± 0.02	1.80 ± 0.04	0.81 ± 0.02	7.70 ± 0.20	3.06 ± 0.07	10.24 ± 0.35
BST16S-14	1.14 ± 0.02	0.17 ± 0.01	0.33 ± 0.01	1.72 ± 0.05	0.80 ± 0.02	2.18 ± 0.09

The pIRIR dating protocol using: (i) the pIR50IR170 signal (Li et al_, 2015b); (ii) the pIR50IR290 signal (Thiel et al_, 2011); and (iii) the pIR200IR290 signal (Li and Li, 2012)_

Step	pIR₅₀IR₁₇₀ dating protocol	Observed	pIR₅₀IR₂₉₀ dating protocol	Observed	pIR₂₀₀IR₂₉₀ dating protocol	Observed
1	Give dose Di^a		Give dose Di^a		Give dose Di^a
2	Preheat at 200°C for 60 s		Preheat at 320°C for 60 s		Preheat at 320°C for 60 s
3	IRSL, 200 s at 50°C	L_x1	IRSL, 200 s at 50°C	L_x1	IRSL, 200 s at 200°C	L_x1
4	pIRIR, 200 s at 170°C	L_x2	pIRIR, 200 s at 290°C	L_x2	pIRIR, 200 s at 290°C	L_x2
5	Give test dose		Give test dose		Give test dose
6	Preheat at 200°C for 60 s		Preheat at 320°C for 60 s		Preheat at 320°C for 60 s
7	IRSL, 200 s at 50°C	T_x1	IRSL, 200 s at 50°C	T_x1	IRSL, 200 s at 200°C	T_x1
8	pIRIR, 200 s at 170°C	T_x2	pIRIR, 200 s at 290°C	T_x2	pIRIR, 200 s at 290°C	T_x2
9			IRSL, 200s bleaching at 325°C		IRSL, 200s bleaching at 325°C
10	Return to 1		Return to 1		Return to 1

Summary of K-feldspar pIRIR age data for samples from Bosten lake Basin_

Sample No.	pIR₅₀IR₁₇₀/pIR₅₀IR₂₉₀/pIR₂₀₀IR₂₉₀ Aliquot	IR₅₀ D_e (Gy)	pIR₅₀IR₁₇₀ D_e (Gy)	IR₅₀ D_e (Gy)	pIR₅₀IR₂₉₀ D_e (Gy)	IR₂₀₀ D_e (Gy)	pIR₂₀₀IR₂₉₀ D_e (Gy)	pIR₅₀IR₁₇₀ OD (%)	pIR₅₀IR₂₉₀ OD (%)	pIR₂₀₀IR₂₉₀ OD (%)	IR₅₀ Age (ka)	pIR₅₀IR₁₇₀ Age (ka)	IR₅₀ Age (ka)	pIR₅₀IR₂₉₀ Age (ka)	IR₂₀₀ Age (ka)	pIR₂₀₀IR₂₉₀ Age (ka)
BST16S-1	11/5/4	0.8±0.3	0.8±0.1	0.3±0.03	2.9±0.2	1.8±0.2	5.4±0.3	72±15	11±4	9±4	0.2±0.1	0.2±0.03	0.1±0.01	0.9±0.1	0.6±0.1	1.7±0.1
BST16S-2	4/8/4	4.6±0.1	7.4±0.3	3.3±0.3	9.3±0.7	5.1±0.6	13.0±0.3	5±2	23±6	4±2	1.3±0.04	2.0±0.1	0.9±0.1	2.5±0.2	1.4±0.2	3.5±0.1
BST16S-3	4/5/4	0.6±0.04	1.3±0.1	0.9±0.1	4.8±0.4	1.8±0.1	6.4±0.2	9±3	15±5	3±2	0.2±0.01	0.4±0.03	0.3±0.03	1.4±0.1	0.5±0.03	1.8±0.1
BST16S-14	11/5/4	0.2±0.1	0.4±0.1	0.4±0.1	3.0±0.2	1.0±0.02	4.0±0.2	53±11	12±4	7±3	0.1±0.03	0.1±0.03	0.1±0.03	0.9±0.1	0.3±0.01	1.3±0.1
BST16S-4	4/4/4	0.8±0.1	3.5±0.3	3.1±0.5	19.2±1.7	6.5±0.2	31.0±1.0	16±6	16±6	4±2	0.2±0.03	0.9±0.1	0.8±0.1	5.0±0.5	1.7±0.1	8.1±0.4
BST16S-5	4/4/5	1.2±0.1	3.4±0.04	1.6±0.2	9.8±0.4	3.9±0.3	15.1±0.7	0	7±3	7±3	0.4±0.03	1.0±0.03	0.5±0.1	2.9±0.1	1.2±0.1	4.5±0.2
BST16S-6	4/4/6	1.8±0.1	5.9±0.2	3.2±0.3	18.2±1.6	7.5±0.4	30.7±1.8	5±2	16±6	10±4	0.5±0.03	1.6±0.1	0.9±0.1	4.9±0.5	2.0±0.1	8.3±0.6
BST16S-7	8/4/4	1.7±0.1	6.0±0.6	2.9±0.1	22.3±1.9	7.9±1.0	33.7±2.6	24±6	15±6	13±5	0.5±0.03	1.6±0.2	0.8±0.04	6.0±0.5	2.1±0.3	9.1±0.8
BST16S-8	8/7/8	2.7±0.9	6.8±0.8	2.9±0.3	20.5±1.6	8.9±1.1	40.2±3.5	32±8	22±6	19±5	0.7±0.2	1.8±0.2	0.8±0.1	5.4±0.5	2.4±0.3	10.7±1
BST16S-9	8/7/9	2.2±0.2	10.9±1.1	4.1±0.6	23.0±1.1	10.2±0.8	38.5±2.9	31±8	14±4	21±5	0.6±0.1	2.8±0.3	1.1±0.2	6.0±0.3	2.7±0.2	10±0.8
BST16S-10	8/5/4	89.0±3.8	160.5±5.5	60.5±5.7	158.2±11.8	86.6±4.1	197.2±14.1	8±2	15±5	11±4	20.4±0.9	36.7±1.4	13.8±1.3	36.2±2.8	19.8±1	45.1±3.3
BST16S-11	4/9/4	3.7±0.2	20.8±2.1	7.6±0.5	46.7±2.8	19.8±1.8	84.9±4.6	17±6	18±4	9±3	0.9±0.05	4.8±0.5	1.8±0.1	10.8±0.7	4.6±0.4	19.7±1.1
BST16S-12	4/5/4	2.2±0.2	19.0±1.8	4.1±0.7	31.0±1.9	18.3±1.8	71.4±6.7	17±6	11±4	16±6	0.5±0.04	4.0±0.4	0.9±0.1	6.5±0.4	3.8±0.4	15±1.4

The location and sediment type of samples from Bosten lake Basin_

Sample No.	Source material	Distance from Lake (km)	Site	Altitude (m)
BST16S-1	Eolian sand dunes	Around 0.05 km	41.88N, 87.22E	1061
BST16S-2	Eolian sand dunes	Around 0.07 km	41.93N, 87.13E	1060
BST16S-3	Eolian sand dunes	Around 0.10 km	41.90N, 86.99E	1055
BST16S-14	Eolian sand dunes	Around 0.19 km	42.08N, 87.02E	1056
BST16S-4	Fluvial sand from Kaidu river	Around 16.29 km	41.97N, 86.64E	1055
BST16S-5	Fluvial sand from Kaidu river	0	41.93N, 86.75E	1051
BST16S-6	Fluvial sand from Kaidu river	Around 3.33 km	41.90N, 86.72E	1050
BST16S-7	Fluvial sand from Kaidu river	Around 36.14 km	42.07N, 86.50E	1061
BST16S-8	Fluvial sand from Kaidu river	Around 48.54 km	42.12N, 86.41E	1067
BST16S-9	Fluvial sand from Kaidu river	Around 78.92 km	42.22N, 86.25E	1078
BST16S-10	Gravel sand from pluvial fans	Around 21.72 km	42.31N, 86.91E	1166
BST16S-11	Gravel sand from pluvial fans	Around 20.45 km	42.30N, 86.91E	1140
BST16S-12	Gravel sand from pluvial fans	Around 19.59 km	42.25N, 87.06E	1114

Dose rate data based on Neutron Activation Analysis for samples from Bosten lake Basin_

Sample No.	Grain size (μm)	U (ppm)	Th (ppm)	K (%)	Observed water content (%)	Life average water content (%)	Internal dose rate (Gy/ka)	Cosmic dose rate (Gy/ka)	Dose rate (Gy/ka)
BST16S-1	90–125	1.58 ± 0.07	4.9 ± 0.17	1.67 ± 0.06	0.20	1 ± 0.5	0.46 ± 0.03	0.33	3.21 ± 0.06
BST16S-2	90–125	1.08 ± 0.06	3.74 ± 0.14	2.29 ± 0.07	0.40	1 ± 0.5	0.46 ± 0.03	0.33	3.66 ± 0.06
BST16S-3	90–125	1.27 ± 0.06	5.18 ± 0.18	1.99 ± 0.06	0.05	1 ± 0.5	0.46 ± 0.03	0.33	3.50 ± 0.06
BST16S-14	90–125	1.44 ± 0.07	5.33 ± 0.18	1.62 ± 0.05	0.03	1 ± 0.5	0.46 ± 0.03	0.33	3.16 ± 0.06
BST16S-4	90–125	2.33 ± 0.09	11.8 ± 0.33	1.79 ± 0.06	4.5	6 ± 3	0.46 ± 0.03	0.33	3.83 ± 0.12
BST16S-5	90–125	1.33 ± 0.07	6.07 ± 0.20	1.94 ± 0.06	24.8	6 ± 3	0.46 ± 0.03	0.33	3.37 ± 0.10
BST16S-6	90–125	1.71 ± 0.08	6.33 ± 0.21	2.03 ± 0.06	32.5	6 ± 3	0.46 ± 0.03	0.33	3.72 ± 0.12
BST16S-7	90–125	1.74 ± 0.08	7.26 ± 0.23	2.13 ± 0.06	1.2	6 ± 3	0.46 ± 0.03	0.33	3.72 ± 0.11
BST16S-8	90–125	1.67 ± 0.08	8.56 ± 0.26	2.09 ± 0.06	2.7	6 ± 3	0.46 ± 0.03	0.33	3.76 ± 0.12
BST16S-9	90–125	1.84 ± 0.08	8.59 ± 0.26	2.13 ± 0.06	8.6	6 ± 3	0.46 ± 0.03	0.33	3.84 ± 0.12
BST16S-10	90–125	2.36 ± 0.09	12.9 ± 0.36	2.05 ± 0.06	2.1	1 ± 0.5	0.46 ± 0.03	0.34	4.37 ± 0.07
BST16S-11	90–125	1.86 ± 0.08	9.82 ± 0.28	2.32 ± 0.07	2.2	1 ± 0.5	0.46 ± 0.03	0.33	4.32 ± 0.07
BST16S-12	90–125	1.97 ± 0.08	12.6 ± 0.35	2.54 ± 0.07	0.2	1 ± 0.5	0.46 ± 0.03	0.33	4.77 ± 0.07

The Bleaching of Different K-Feldspar pIRIR Signals of Source Materials of Lacustrine Sediment – A Case Study from Bosten Lake Basin in Arid Central Asia

Figures & Tables

Fig. 1

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Fig. 8

Summary of the residual dose after 112 h bleaching under sunlight for all samples from Bosten lake Basin_

The pIRIR dating protocol using: (i) the pIR50IR170 signal (Li et al_, 2015b); (ii) the pIR50IR290 signal (Thiel et al_, 2011); and (iii) the pIR200IR290 signal (Li and Li, 2012)_

Summary of K-feldspar pIRIR age data for samples from Bosten lake Basin_

The location and sediment type of samples from Bosten lake Basin_

Dose rate data based on Neutron Activation Analysis for samples from Bosten lake Basin_

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