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ESR dating of sea-floor hydrothermal barite: contribution of 228Ra to the accumulated dose Cover

ESR dating of sea-floor hydrothermal barite: contribution of 228Ra to the accumulated dose

Geochronometria
Volume 43 (2016): Issue 1 (February 2016)
By: Shin Toyoda,  Taisei Fujiwara,  Ai Uchida and  Jun-Ichiro Ishibashi  
Open Access
|Dec 2016

Figures & Tables

Radioactive decay chains from (a) 226Ra and (b) 228Ra.
The results of simulation as a function of time of the accumulated doses given by radioactive nuclei 226Ra to 214Po (indicated by 226Ra), 210Pb to 206Pb (indicated by 210Pb), 228Ra and 228Ac (indicated by 228Ra), and 228Th to 208Pb (indicated by 228Th). The values are calculated for HPD1621R03, taken at a sea-floor hydrothermal area at depth of 1495 m of Hatoma Knoll, Okinawa Trough, the ESR age of which was estimated to be 33 years while the bulk concentrations of 226Ra and 228Ra are estimated to be 17.0 Bq/g and 59.4 Bq/g, respectively.
The contributions to the accumulated dose as a function of time of the nuclei, 226Ra to 214Po (indicated by 226Ra), 210Pb to 206Pb (indicated by 210Pb), 228Ra and 228Ac (indicated by 228Ra), and 228Th to 208Pb (indicated by 228Th) in %, calculated from the values in Fig. 1.
The contribution to the accumulated dose from 228Ra series as a function of time in logarithmic scale.
The total of the accumulated dose as a function of time up to 10 ka. The accumulated dose saturates due to decay of 226Ra.

Experimental results for HPD1621R03 to be used for the simulation of the contribution of 228Ra and daughter nuclei to the accumulated doses in barite_

DE (Gy)20.8−1.5+1.6 $20.8_{-1.5}^{+1.6}$
Barite content (%)70.0
Water content (%)30.3
Bulk 226Ra concentration (Bq/g)16.9
Bulk 228Ra concentration (Bq/g)1.02
ESR age (a)33±1
Initial bulk 226Ra concentration (Bq/g)17.0
Initial bulk 228Ra concentration (Bq/g)59.4
Initial 228Ra/226Ra activity ratio3.47
DOI: https://doi.org/10.1515/geochr-2015-0042 | Journal eISSN: 1897-1695
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Language: English
Page range: 201 - 206
Submitted on: Feb 19, 2016
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Accepted on: Sep 21, 2016
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Published on: Dec 30, 2016
Published by: Sciendo
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
ESR,
dating,
barite,
disequilibrium,
hydrothermal,
radiation
Related subjects:
Geosciences,
Geosciences, other

© 2016 Shin Toyoda, Taisei Fujiwara, Ai Uchida, Jun-Ichiro Ishibashi, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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