Complex Dose Rate Calculations in Luminescence Dating of Lacustrine and Palustrine Sediments from Niederweningen, Northern Switzerland

Frank Preusser; Detlev Degering; Alexander Fülling; Johannes Miocic

doi:10.2478/geochr-2023-0003

Figures & Tables

(A) – Map indicating the location of the study area in the Swiss Alpine foreland with the extent of the LGM ice cover (blue-green) and overdeepened structures below the present day land surface (grey). (B) – Detailed map of the Wehntal with the location of previous (white circles) and present (black circles) sites investigated in the village of Niederweningen (modified after Dehnert et al., 2012). LGM, last glaciation maximum.

Logs of the cores NW2018/2 and NW2018/3 illustrating the LTs, lithology and OSL sample locations as well as the layer model used for the individual OSL samples. LTs, lithotypes; OSL, optically stimulated luminescence.

Characterisation of luminescence properties exemplified for sample NW19-3-8. Shown are (A) OSL and (B) IRSL decay curves together with the sensitivity change observed during the course of the SAR protocol (plot of Tn/Tx), (C) dose–response curves for both OSL and IRSL, and (D) plot of mean (CAM) OSL versus IRSL De values. IRSL, infrared stimulated luminescence; OSL, optically stimulated luminescence; SAR, single-aliquot regenerative dose; CAM, Central Age Model.

Gamma ray spectrum of the reference loess material (Koeln Loess). Sample weight: 160.5 g, measurement time: 584,786 s. Selected peaks are labelled with the corresponding nuclide names, red: U-238 daughter nuclides, blue: Th-232 daughter nuclides. The inset focusses on the lower energy range of the spectrum from 0 keV to 400 keV.

Comparison of the results of NAA and HR-GS for potassium (A,B), thorium (C,D) and uranium (E,F). HR-GS, high-resolution gamma spectrometry; NAA, neutron activation analyses.

Sediment moisture at the time of sampling plotted versus water absorption capacity. Note that the water absorption capacity of all samples is higher than the sediment moisture. The organic content also influences the water content, with samples with a high organic content featuring higher water contents. Dashed = 1:1 line, dotted line: y = x + 25.

Illustrating the impact of different water contents on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). A and C show the absolute values, whereas B and D display the ratio in comparison to the estimated water content. Closed circles (scenario 1): sediment moisture determined after sampling. Triangles (scenario 2): maximum water adsorption capacity measured in the laboratory, including adding 25% for peat samples. Open circles (scenario 3): estimated long-term water content based on the sediment properties and the water contents determined by scenarios 1 and 2. Scenario 3 is our preference and is used in the following when applying other correction factors than water content. IRSL, infrared stimulated luminescence.

Illustration of the layer model used to analyse the impact of inhomogeneous radiation fields. The parameters t, x1 and x2 describe the location of the sample within the stratigraphic setting.

Boxplots of the radionuclide content of each LT. (A) – Potassium, (B) – thorium, (C) – uranium. Note the high variations in K and Th content for LT 2b (silty, organic-rich clays). HRGS, high-resolution gamma spectrometry; LT, lithotype.

Illustrating the impact of layer correction on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D), both given as absolute values and a ratio in comparison to the age calculated without layer correction (using the estimated water content, as discussed in Section 4.2). IRSL, infrared stimulated luminescence.

Illustrating the impact of different scenarios of correction for radioactive disequilibrium on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). The central column represents a simplified stratigraphy of the sediment sequence for comparison; details are given in Fig. 6. IRSL, infrared stimulated luminescence.

Listing the three different water contents used to test the influence of water content on dose rate calculations_

Sample	Litho-type	Organic content (%)	Sediment moisture (%)	Water absorption capacity (%)	Water absorption + 25% (%)	Long-term content (%)
NW18/2-11	3f	3	15	38	-	25 ± 5
NW18/2-10	3f	5	20	41	-	30 ± 5
NW18/2-09	3f	3	12	34	-	25 ± 5
NW18/2-21	1b	51	-	160	200	180 ± 10
NW18/2-08	2b	47	96	100	125	110 ± 10
NW18/2-22	2b	36	73	95	119	100 ± 10
NW18/2-23	1a	24	40	96	120	100 ± 10
NW18/2-07	3d	18	57	74	92	75 ± 5
NW18-2-24	1c	51	21	68	85	75 ± 5
NW18/2-06	2b	20	43	77	96	75 ± 5
NW18/2-25	3c	7	-	62	-	60 ± 5
NW18/2-05	3c	2	25	50	-	40 ± 5
NW18/3-11	3f	17	24	48	-	40 ± 5
NW18/3-21	3f	24	-	64	-	55 ± 5
NW18/3-10	2b	6	27	59	-	45 ± 5
NW18/3-09	3f	3	17	40	-	30 ± 5
NW18/3-22	1b	20	35	54	67	60 ± 5
NW18/3-23	3c	15	29	54	67	60 ± 5
NW18/3-08	3b	2	19	42	-	35 ± 5

Overview of samples and their sedimentary context_

Sample	Depth (cm)	Sedimentary context
NW18/2-11	148	Located within a thick sequence of light grey to dark grey sandy, muddy silts
NW18/2-10	224	Same as aNW18/2-11, with the sand fraction more dominant
NW18/2-09	375	Located about 40 cm above the peat-rich interval in a dark grey silt, with 15–cm-thick organic-rich silty clay separating the sampled silt from the uppermost peat
NW18/2-21	430	Within the topmost muddy-silty peat, which has a thickness of ~30 cm. Over and underlain by organic-rich silty clays
NW18/2-08	442	Located at the top of 20-cm-thick silty clay, which sits in between two at least 30-cm-thick compacted silty peat layers
NW18/2-22	455	Same as NW18/2-08 but at the bottom of the silty clay layer
NW18/2-23	530	Within a thin (~15 cm) silty gyttia layer, which is over and underlain by black muddy peats with few wood fragments
NW18/2-07	545	Within a thin (~10 cm) organic-rich sandy silt with plant remains. Overlain by black muddy peats and underlain by a dark brown peat with many large wood fragments
NW18-2-24	570	Within a dark brown silty peat with many large wooden fragments, overlain by a thin (~10 cm) organic-rich sandy silt with plant remains and overlying a thick dark grey silty clay with organic-rich layers
NW18/2-06	610	Located at the top of dark grey silty clay with organic-rich layers, overlain by a dark grey organic-rich silt
NW18/2-25	749	Located within a thin (~15 cm) light grey to white silt with small plant remains and mollusc shells which is interbedded between a black muddy peat (top) and silty gyttia (bottom)
NW18/2-05	788	Within a thick light grey silt with mollusc shells
NW18/3-11	232	Located within a grey sandy, pebbly silt with plant remains. Overlain by a graded sand and overlying a compacted thin black silty peat
NW18/3-21	323	A thin (8 cm) grey silt with small plant remains, interbedded within compacted silted peats
NW18/3-10	335	Dark grey silty organic-rich clay, over and underlain by very thin (<5 cm) silt and sandy layers which are packaged within black peats
NW18/3-09	406	Within a dark grey sandy silt with plant remains and peat fragments. Overlain by a dark grey pebbly sand and underlain by a black compacted peat
NW18/3-22	438	Within a thick (~45 cm) black peat layer, which is over and underlain by organic-rich grey silts
NW18/3-23	496	Within a thin (10 cm) light grey silt with mollusc shells. Overlain by a dark brown organic-rich sand silt and overlying a thin layer of black peat
NW18/3-08	518	At the top of a thick (>1 m) light grey sandy silt, overlain by an organic-rich sand silt with small plant remains

Mean De values (CAM) and resulting ages with sample code, composite depth and number of replicate measurement (quartz/feldspar) for OSL and IRSL_

Sample	Depth (cm)	n	OSL D_e (Gy)	IRSL D_e (Gy)	OSL Age1 (ka)	OSL Age2 (ka)	OSL Age3 (ka)	IRSL Age1 (ka)	IRSL Age2 (ka)	IRSL Age3 (ka)
NW18/2-11	148	5/7	303.9 ± 8.7	341.6 ± 11.6	105 ± 5	105 ± 5	103...107 ± 5	107 ± 7	107 ± 7	105...109 ± 7
NW18/2-10	224	5/7	235.4 ± 4.7	302.8 ± 9.3	79.6 ± 3.3	79.8 ± 3.3	80...81 ± 3	93.1 ± 6.1	93.3 ± 6.1	94...95 ± 6
NW18/2-09	375	5/7	212.3 ± 4.8	190.8 ± 3.3	85.6 ± 3.6	85.5 ± 3.6	86...87 ± 4	70.9 ± 3.9	70.8 ± 3.9	71...72 ± 4
NW18/2-21	430	-/6	-	206.3 ± 5.1	-	-	-	171 ± 13	167 ± 13	177...197 ± 13
NW18/2-08	442	-/7	-	191.8 ± 7.0	-	-	-	74.1 ± 6.4	77.8 ± 7.0	91...96 ± 7
NW18/2-22	455	5/6	165.9 ± 10.0	223.1 ± 5.2.4	100.1 ± 7.6	103.9 ± 7.9	109...115 ± 8	119 ± 9	123 ± 10	129...138 ± 10
NW18/2-23	530	-/6	-	148.9 ± 5.5	-	-	-	37.5 ± 3.7	39.9 ± 4.2	28...32 ± 3
NW18/2-07	545	-/7	-	197.8 ± 3.6	-	-	-	64.5 ± 5.0	66.3 ± 5.2	66...69 ± 5
NW18-2-24	570	-/6	-	254.7 ± 7.5	-	-	-	125 ± 7	115 ± 10	87...102 ± 8
NW18/2-06	610	-/7	-	248.0 ± 4.6	-	-	-	68.8 ± 5.5	68.8 ± 5.5	69...71 ± 6
NW18/2-25	749	5/6	246.50 ± 9.0	310.80 ± 8.7	144 ± 8	135 ± 7	118...134 ± 7	164 ± 11	155 ± 10	133...151 ± 11
NW18/2-05	788	-/7	-	170.8 ± 4.6	-	-	-	84.4 ± 5.5	84.4 ± 5.5	no dis.
NW18/3-11	232	5/7	202.6 ± 6.5	198.4 ± 5.2	67.9 ± 3.5	69.0 ± 3.5	70 ± 4	59.7 ± 4.2	60.7 ± 2.7	61 ± 4
NW18/3-21	323	5/6	181.8 ± 10.4	243.0 ± 5.7	67.0 ± 4.7	72.9 ± 5.3	73...74 ± 5	79.7 ± 5.8	86.0 ± 6.7	86...88 ± 7
NW18/3-10	335	5/6	276.0 ± 6.3	288.0 ± 7.6	82.5 ± 3.7	85.2 ± 3.9	no dis.	77.3 ± 5.4	79.6 ± 5.7	no dis.
NW18/3-09	406	-/7	-	310.8 ± 6.6	-	-	-	92.6 ± 7.5	93.5 ± 5.9	89...93 ± 6
NW18/3-22	438	-/6	-	242.9 ± 5.8	-	-	-	86.2 ± 6.6	85.9 ± 6.5	89...96 ± 7
NW18/3-23	496	5/5	202.2 ± 6.0	236.2 ± 7.3	97.0 ± 4.5	97.1 ± 4.5	no dis.	102 ± 7	103 ± 7	no dis.
NW18/3-08	518	5/7	239.8 ± 5.7	259.7 ± 4.9	102 ± 5	101 ± 4	no dis.	99.9 ± 6.2	99.5 ± 6.1	no dis.

Calculated dose rate data with sample code and composite depth, and estimated long-term water content_

Sample	Depth (cm)	W (%)	Dose rate Q1 (Gy ka⁻¹)	Dose rate Q2 (Gy ka⁻¹)	Dose rate Q3 (Gy ka⁻¹)	Dose rate F1 (Gy ka⁻¹)	Dose rate F2 (Gy ka⁻¹)	Dose rate F3 (Gy ka⁻¹)
NW18/2-11	148	25 ± 5	2.89 ± 0.14	2.89 ± 0.14	2.84...2.94 ± 0.16	3.18 ± 0.22	3.18 ± 0.22	3.12...3.24 ± 0.25
NW18/2-10	224	30 ± 5	2.96 ± 0.12	2.95 ± 0.12	2.91...2.93 ± 0.13	3.25 ± 0.21	3.24 ± 0.21	3.18...3.21 ± 0.23
NW18/2-09	375	25 ± 5	2.48 ± 0.10	2.48 ± 0.10	2.44...2.47 ± 0.12	2.69 ± 0.15	2.70 ± 0.15	2.66...2.69 ± 0.15
NW18/2-21	430	180 ± 10	-	-	-	1.21 ± 0.09	1.23 ± 0.09	1.05...1.17 ± 0.09
NW18/2-08	442	110 ± 10	-	-	-	2.59 ± 0.22	2.46 ± 0.22	1.99...2.10 ± 0.19
NW18/2-22	455	100 ± 10	1.66 ± 0.13	1.60 ± 0.12	1.44...1.53 ± 0.15	1.88 ± 0.15	1.82 ± 0.14	1.61...1.73 ± 0.14
NW18/2-23	530	100 ± 10	-	-	-	3.97 ± 0.40	3.73 ± 0.39	4.59 ± 0.51
NW18/2-07	545	75 ± 5	-	-	-	3.07 ± 0.24	2.98 ± 0.23	2.85...2.98 ± 0.23
NW18-2-24	570	75 ± 5	-	-	-	3.12 ± 0.27	3.10 ± 0.27	2.51...2.94 ± 0.27
NW18/2-06	610	75 ± 5	-	-	-	3.61 ± 0.29	3.60 ± 0.29	3.50...3.58 ± 0.29
NW18/2-25	749	60 ± 5	1.71 ± 0.09	1.82 ± 0.09	1.84...2.09 ± 0.13	1.89 ± 0.12	2.00 ± 0.12	2.06...2.34 ± 0.18
NW18/2-05	788	40 ± 5	-	-	-	2.02 ± 0.19	2.02 ± 0.19	no dis.
NW18/3-11	232	40 ± 5	2.98 ± 0.15	2.93 ± 0.15	2.88...2.90 ± 0.17	3.32 ± 0.23	3.27 ± 0.15	3.24...3.25 ± 0.24
NW18/3-21	323	55 ± 5	2.72 ± 0.19	2.49 ± 0.18	2.47...2.49 ± 0.23	3.05 ± 0.22	2.82 ± 0.22	2.75...2.81 ± 0.23
NW18/3-10	335	45 ± 5	3.35 ± 0.15	3.24 ± 0.15	no dis.	3.73 ± 0.26	3.62 ± 0.26	no dis.
NW18/3-09	406	30 ± 5	-	-	-	3.36 ± 0.27	3.32 ± 0.21	3.34...3.51 ± 0.24
NW18/3-22	438	60 ± 5	-	-	-	2.82 ± 0.21	2.83 ± 0.21	2.54...2.74 ± 0.21
NW18/3-23	496	60 ± 5	2.01 ± 0.11	2.08 ± 0.10	no dis.	2.31 ± 0.15	2.30 ± 0.15	no dis.
NW18/3-08	518	35 ± 5	2.36 ± 0.10	2.37 ± 0.10	no dis.	2.60 ± 0.16	2.61 ± 0.16	no dis.

Concentration of dose rate-relevant elements (K, Th, U) determined by both NAA and HR-GS_

Sample	Depth (cm)	K_NAA (%)	K_GS (%)	Th_NAA (ppm)	Th_GS (ppm)	U-238_NAA (ppm)	U-238_GS (ppm)	Ra-226_GS (ppm UE)	U/Ra Ratio
Loess Ref	-	1.11 ± 0.01	1.11 ± 0.01	8.27 ± 0.21	8.27 ± 0.21	2.75 ± 0.09	2.75 ± 0.09	-	-
Loess Test	-	1.04 ± 0.06	1.08 ± 0.02	7.68 ± 0.39	8.27 ± 0.45	2.49 ± 0.19	2.33 ± 0.23	2.62 ± 0.13	-
NW18/2-11	148	1.85 ± 0.09	1.68 ± 0.03	8.2 ± 0.4	7.86 ± 0.17	2.01 ± 0.10	2.02 ± 0.13	2.99 ± 0.08	0.67
NW18/2-10	224	1.72 ± 0.09	1.85.0.04	8.7 ± 0.4	8.26 ± 0.16	8.38 ± 0.42	7.36 ± 0.20	3.19 ± 0.06	2.31
NW18/2-09	375	1.65 ± 0.08	1.75 ± 0.04	5.8 ± 0.3	5.34 ± 0.18	3.37 ± 0.22	2.94 ± 0.14	2.14 ± 0.06	1.37
NW18/2-21	430	0.61 ± 0.03	0.70 ± 0.02	7.0 ± 0.4	7.54 ± 0.30	5.03 ± 0.30	7.30 ± 0.24	4.46 ± 0.13	1.64
NW18/2-08	442	1.07 ± 0.06	1.31 ± 0.03	9.2 ± 0.5	10.51 ± 0.20	5.20 ± 0.31	6.57 ± 0.27	5.66 ± 0.35	1.16
NW18/2-22	455	0.90 ± 0.05	0.96 ± 0.02	7.9 ± 0.4	8.28 ± 0.26	4.69 ± 0.27	5.98 ± 0.27	4.49 ± 0.15	1.33
NW18/2-23	530	0.79 ± 0.04	0.86 ± 0.02	11.6 ± 0.6	12.59 ± 0.36	22.20 ± 1.11	29.03 ± 0.64	15.24 ± 0.27	1.90
NW18/2-07	545	1.31 ± 0.07	1.44 ± 0.03	9.1 ± 0.5	9.18 ± 0.31	13.79 ± 0.68	12.29 ± 0.35	7.56 ± 0.21	1.63
NW18-2-24	570	0.81 ± 0.04	0.84 ± 0.02	8.8 ± 0.4	8.70 ± 0.20	21.47 ± 1.09	24.88 ± 0.58	9.42 ± 0.09	2.64
NW18/2-06	610	1.22 ± 0.06	1.46 ± 0.03	16.4 ± 0.8	17.15 ± 0.35	9.80 ± 0.47	9.79 ± 0.32	7.80 ± 0.22	1.26
NW18/2-25	749	1.16 ± 0.06	1.25 ± 0.03	8.5 ± 0.4	8.70 ± 0.20	5.62 ± 0.36	5.14 ± 0.20	3.88 ± 0.13	1.32
NW18/2-05	788	1.13 ± 0.06	1.21 ± 0.03	6.7 ± 0.3	6.55 ± 0.14	2.05 ± 0.1	1.73 ± 0.12	2.05 ± 0.13	0.85
NW18/3-11	232	1.52 ± 0.08	1.69 ± 0.04	9.5 ± 0.5	9.92 ± 0.09	12.57 ± 0.68	12.10 ± 0.33	4.34 ± 0.18	2.79
NW18/3-21	323	1.44 ± 0.07	1.47 ± 0.03	11.5 ± 0.6	11.96 ± 0.39	5.62 ± 0.24	6.71 ± 0.24	4.67 ± 0.07	1.44
NW18/3-10	335	1.84 ± 0.09	1.98 ± 0.04	14.4 ± 0.7	14.13 ± 0.22	4.17 ± 0.21	4.00 ± 0.20	4.45 ± 0.07	0.90
NW18/3-09	406	1.86 ± 0.10	1.92 ± 0.04	10.9 ± 0.6	10.21 ± 0.22	2.57 ± 0.17	2.14 ± 0.13	2.93 ± 0.03	0.73
NW18/3-22	438	1.20 ± 0.06	1.28 ± 0.03	8.8 ± 0.4	8.32 ± 0.19	8.03 ± 0.40	8.48 ± 0.26	5.73 ± 0.12	1.48
NW18/3-23	496	1.47 ± 0.08	1.53 ± 0.03	8.5 ± 0.4	8.38 ± 0.13	3.03 ± 0.20	3.05 ± 0.16	2.95 ± 0.06	1.03
NW18/3-08	518	1.40 ± 0.07	1.53 ± 0.03	8.6 ± 0.4	8.22 ± 0.17	2.50 ± 0.17	2.17 ± 0.14	2.39 ± 0.08	0.91

Results of repeated gamma spectrometry measurements of reference material ‘Koeln Loess’ in comparison with NAA and reference values_

Parent nuclide	Daughter nuclide	Energy (keV)	Meas. 1 12/2019	Meas. 2 06/2020	Meas. 3 10/2020	Meas. 4 4/2021	NAA	*Reference Potts et al. (2003) (IAG, 2022)*

			Activity (Bq/kg)
U-238	Th-234	63.3	28.0 ± 1.2	35.6 ± 1.4	33.9 ± 1.4	34.3 ± 1.4
	Pb-214	295.2	32.1 ± 0.7	34.1 ± 0.7	33.8 ± 0.7	34.2 ± 0.7
	Pb-214	351.9	32.0 ± 0.7	33.2 ± 0.7	33.6 ± 0.7	33.3 ± 0.7
	Bi-214	609.3	31.9 ± 0.7	33.3 ± 0.7	33.5 ± 0.7	33.0 ± 0.7
	Bi-214	1120.3	29.5 ± 0.6	36.5 ± 0.8	33.5 ± 0.7	35.1 ± 0.7
	Bi-214	1764.5	32.8 ± 0.7	34.1 ± 0.7	33.6 ± 0.7	32.7 ± 0.7
	Mean		31.6 ± 1.3	34.2 ± 1.3	33.6 ± 0.1	33.6 ± 0.9
Concentration	(ppm)		2.56 ± 0.10	2.77 ± 0.10	2.72 ± 0.01	2.72 ± 0.08	2.49 ± 0.19	2.70 ± 0.19 (2.75 ± 0.09)
Th-232	Ac-228	338.3	32.4 ± 0.7	32.5 ± 0.7	34.1 ± 0.8	32.0 ± 0.7
	Ac-228	911.1	34.0 ± 0.8	32.9 ± 0.7	32.4 ± 0.7	32.7 ± 0.7
	Ac-228	969.1	34.2 ± 0.8	33.3 ± 0.7	31.7 ± 0.7	31.7 ± 0.7
	Pb-212	238.6	32.1 ± 0.6	33.3 ± 0.7	33.1 ± 0.7	32.8 ± 0.6
	Tl-208	583.2	33.3 ± 0.8	33.7 ± 0.8	33.0 ± 0.7	33.6 ± 0.8
	Mean		33.1 ± 1.0	33.1 ± 0.5	32.8 ± 1.8	32.5 ± 0.7
Concentration	(ppm)		8.16 ± 0.24	8.16 ± 0.12	8.10 ± 0.45	8.02 ± 0.17	7.68 ± 0.39	8.11 ± 0.47 (8.27 ± 0.21)
K-40	-	1460.8	339.1 ± 7.0	336.5 ± 6.8	335.0 ± 6.8	335.6 ± 6.8
Concentration	(%)		1.10 ± 0.02	1.09 ± 0.02	1.08 ± 0.02	1.09 ± 0.02	1.04 ± 0.06	1.08 ± 0.02 (1.11 ± 0.01)

Complex Dose Rate Calculations in Luminescence Dating of Lacustrine and Palustrine Sediments from Niederweningen, Northern Switzerland

Figures & Tables

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Fig 10.

Fig 11.

Listing the three different water contents used to test the influence of water content on dose rate calculations_

Overview of samples and their sedimentary context_

Mean De values (CAM) and resulting ages with sample code, composite depth and number of replicate measurement (quartz/feldspar) for OSL and IRSL_

Calculated dose rate data with sample code and composite depth, and estimated long-term water content_

Concentration of dose rate-relevant elements (K, Th, U) determined by both NAA and HR-GS_

Results of repeated gamma spectrometry measurements of reference material ‘Koeln Loess’ in comparison with NAA and reference values_

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