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A new method for constructing Pb-210 chronology of young peat profiles sampled with low frequency Cover

A new method for constructing Pb-210 chronology of young peat profiles sampled with low frequency

Geochronometria
Volume 46 (2019): Issue 1 (January 2019)
By: Jarosław Sikorski  
Open Access
|Feb 2019

Figures & Tables

Fig. 1

Location of the sites.

Fig. 2

Specific activity of the 210Pb for measured samples (black circles) and using approximation of activity (red squares).

Fig. 3

Activities (the upper chart) and age-depth models (the lower chart), obtained for different values of c parameter (c = 2 – black diamonds, c = 2.5 – red squares, c = 3 – blue circles), for BB3 core.

Fig. 4

Specific activity of the 210Pb obtained using the approximation of activity (red squares) for BB3 and BB4 cores, and after their shortening (black circles).

Fig. 5

Age calculated from the CRS dating model for measured activity (black circles) and using approximation of activity (red squares).

Fig. 6

Age-depth models obtained by activity approximation (red) and SIT (brown), Mod-Age (black), OxCal (green), Clam (blue), Bacon (purple) models. For the sake of clarity, the presented charts show the uncertainties (68.2%) for activity approximation only, as well as in the lower layers of the cores for the models that diverge most seriously from the proposed model. This is the case for SIT model for all the cores, and for BB3 and BM4 in the case of Bacon model, and BB4, BM3, and BM4 in the case of Mod-Age model.

Fig. 7

Examples of age-depth models obtained by Bacon model for cores TW1 (left) and BM4 (right). Note that the models are not matched to the points corresponding to the maximum probability; they only tend to the linearization.

Parameters a, b, c of the functions obtained in TableCurve program_

Coreabc
BB36.093(45)–0.391(52)2.5
BB3 shortened6.148(52)–0.486(77)2.5
BB46.175(26)–0.499(38)2.5
BB4 shortened6.220(26)–0.618(45)2.5
BM36.063(39)–0.420(61)2.5
BM3 shortened6.062(49)–0.417(80)2.5
BM46.022(36)–0.198(35)3.0
BM4 shortened6.018(40)–0.187(41)3.0

Average growth rates of the investigated peat bogs_

Average growth rates (mm/y)
Coreby 1967from 1967 to present times
weighted average weighted average
BB31.03(12)1.10(13)3.41(19)3.21(18)
BB41.21(15)3.04(18)
BM31.15(13)0.99(12)3.26(18)3.40(18)
BM40.87(11)3.54(18)
TW11.34(16)
TW21.41(17)

Comparison of measured and approximated values of supported 210Pb_

CoreDepth (cm)Measured values of supported 210Pb (Bq/kg)Approximated values of supported 210Pb (Bq/kg)t-testp-value
BB329.512.2(81)14.7(91)0.210.84
BB429.515.3(83)13.8(90)0.120.91
BM331.520.8(95)22.9(99)0.150.88
BM429.523.4(96)23.1(98)0.020.98
DOI: https://doi.org/10.1515/geochr-2015-0101 | Journal eISSN: 1897-1695
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Language: English
Page range: 1 - 14
Submitted on: Jul 4, 2018
|
Accepted on: Jan 4, 2019
|
Published on: Feb 6, 2019
Published by: Sciendo
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
Pb-210 chronologies,
young peat profiles,
210Pb dating,
CRS,
age-depth model
Related subjects:
Geosciences,
Geosciences, other

© 2019 Jarosław Sikorski, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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