The alpha effectiveness of the dating ESR signal in barite

Toyoda, Shin; Sato, Fumihiro; Nishido, Hirotsugu; Kayama, Masahiro; Ishibashi, Jun Ichiro

doi:10.1016/j.radmeas.2012.04.016

Cited by 9 publications

(11 citation statements)

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“…In our project, two geochronological methods to be applied to the hydrothermal ore minerals consisted mainly of sulfides and sulfates were newly developed: (1) electron spin resonance dating (ESR dating) was applied mainly to barite (BaSO 4 ) (Fujiwara et al Chap. 34;Toyoda et al 2012), and (2) uranium-thorium disequilibrium dating (U-Th dating) was applied to hydrothermal sulfide minerals consisting mainly of pyrite and sphalerite (Ishibashi et al Chap. 23;Takamasa et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses

Kumagai

Watanabe

Yahagi

et al. 2014

Subseafloor Biosphere Linked to Hydrothermal Systems

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To elucidate the evolution of hydrothermal activities, we conducted an interdisciplinary study including geochemistry and biology to develop a method of obtaining reliable age information. As geochemical dating techniques, two methods applicable for hydrothermal ore minerals were developed and improved: electron spin resonance method and uranium-thorium disequilibrium method. Cross checks between the two methods generally showed good agreement for the range of hundreds to thousands of years. As biological analysis, the biodiversity among faunal communities in the targeted areas was analyzed at the species and DNA levels. Species and genetic diversity of the local fauna were not always correlated to geochemical dating, either in the southern Mariana Trough region or in the Okinawa Trough region. Although the results are not simple, comparison of age information obtained from analyses of these two disciplines potentially provides important constraints for discussion of the history and evolution of hydrothermal activities.

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Section: Introductionmentioning

confidence: 99%

“…Within sulfate minerals, barite was chosen as the target mineral because the obtained signals are clear. To estimate the in-situ dose-rate in a deepsea environment, we calibrated yields of the ESR signals in a known/measured dose-rate as reported by Toyoda et al (2012). Such a dose rate includes α-radiation using an Al 2 O 3 -target.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses

Kumagai

Watanabe

Yahagi

et al. 2014

Subseafloor Biosphere Linked to Hydrothermal Systems

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“…Assuming that Ra is populated only in barite as confirmed by Okumura et al (2010), the internal and external dose rates of alpha, beta and gamma rays given to the barite minerals were calculated (Toyoda et al 2014). The alpha effectiveness of 0.043 was adopted (Toyoda et al 2012). Corrections were made for water content, beta ray attenuation for grain sizes (a plane with 20 μm in thickness as confirmed by thin section).…”

Section: Methodsmentioning

confidence: 99%

ESR Dating of Barite in Sea-Floor Hydrothermal Sulfide Deposits in the Okinawa Trough

Fujiwara

Toyoda

Uchida

et al. 2014

Subseafloor Biosphere Linked to Hydrothermal Systems

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ESR (electron spin resonance) ages were determined for barite crystals extracted from hydrothermal sulfide deposits taken at Daiyon-Yonaguni Knoll field, Hatoma Knoll field, Iheya North Knoll field, Hakurei Site of Izena Hole field, Yoron Hole field of the Okinawa Trough. The ages range from 4.1 to 16,000 years, being consistent with detection of 228 Ra in younger samples and radioactive equilibrium/disequilibrium between radium and daughter nuclei. The variation of the ages within each sample is mostly within the statistical error range. The relative order of the ages is consistent with the result of 226 Pb method, but the determining absolute ages is still an issue. The order of ages of the 5 hydrothermal fields would be arranged, from young to old as follows; Yoron Hole field, Daiyon-Yonaguni Knoll field, Hatoma Knoll field, being nearly equal to Iheya North Knoll field. KeywordsBarite Dating Electron spin resonance Hydrothermal activities IntroductionThere have been many scientific efforts devoted for studies on active sea-floor hydrothermal fields found in Okinawa Trough (Ishibashi et al. Chap. 23). The evolution of these hydrothermal fields is one of the important issues. Dating methods have been employed for hydrothermal sulfide deposits, such as the U-Th disequilibrium method (e.g. You and Bickle 1998) applicable for the age range more than several thousand years, and 226 Pb and 228 Th method (e.g. Noguchi et al. 2011) for the range less than 150 years. The age range of several hundred years is essential to estimate the life time of hydrothermal activities. However, dating methods for the age range are lacking. Okumura et al. (2010) made the first practical application of ESR dating technique to a sample of seafloor hydrothermal barite to obtain ages of 300 and 3,620 years, while Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Toyoda et al. (2011) determined the optimum ESR condition while Sato et al. (2011) confirmed that the signal is thermally stable enough for an age range of several thousand years.Seafloor massive sulfide deposits are composed of sulfide minerals such as pyrite, sphalerite, chalcopyrite and galena, and also include sulfate minerals such as anhydrite and barite. The sulfate minerals precipitate by mixing of hydrothermal fluid and seawater, while the sulfide minerals precipitate from the hydrothermal fluid mainly by cooling (Hannington et al. 1995). It is generally considered that a combination and/or switch of these two modes of hydrothermal precipitation lead to growth of sulfide structures such as a chimney and mound and that of large hydrothermal T. Fujiwara S. Toyoda (*) A. Uchida Okayama University of Science, Okayama, Japan e-mail: toyoda@dap.ous.ac.jp deposits (e.g. Tivey 2007). Takamasa et al. (2013) determined ESR ages for barite in sulfide deposits in the South Mariana Trough hydrothermal field, and concluded that the ages are consistent with U-Th ages. In this study, the ages of various hydrothermal sulfides in the Okinawa Trough a...

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“…Using the Eqs. 2.1 to 2.4 with the corrections for the water content and for the grain size which is typically 20 μm in thickness (Fujiwara et al, 2015), with the alpha effectiveness value of 0.043 (Toyoda et al, 2012), and with the consideration for the external and internal β doses, the ESR age for this present sample was estimated to be 33 ± 1 ka as shown in Table 1.…”

Section: The Analysis For the Test Samplementioning

confidence: 98%

“…Kasuya et al (1991) investigated the dose responses of the electron spin resonance (ESR) signals observed in natural barite samples and first pointed out that ESR dating of barite is possible. Following Okumura et al (2010), who made the first practical application of ESR dating to a sample of seafloor hydrothermal barite with the signal due to SO 3 -, basic studies on ESR dating of barite were performed by Toyoda et al (2011) for the optimum conditions of ESR measurements of the dating signal, by Sato et al (2011) for the thermal stability of the signal, and by Toyoda et al (2012) for the alpha effectiveness value. Takamasa et al (2013) examined sulfide deposits in the South Mariana Trough sea-floor hydrothermal field to compare the ESR ages obtained for barite and the U-Th ages for sulfide minerals extracted from the same portions.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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Electron spin resonance (ESR) dating of barite has been recently developed and is now practically applied to barite extracted from sea-floor hydrothermal deposits. The evolution of the accumulated dose to barite is simulated for an actual sample of barite in sea-floor hydrothermal sulfide deposit to find that the contribution of radioactive nuclei of 228 Ra series can be important for the samples younger than 300 years old. Currently, any date over 50 years should be considered a maximum value when the 228 Ra content is not obtained. The method to estimate the contribution from 228 Ra series has to be developed in future for those in which 228 Ra is not detected. The age limit of ESR dating of barite would be 5000 to 6000 years due to the decay of 226 Ra, which is also found by simulation of the accumulated dose.

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The alpha effectiveness of the dating ESR signal in barite

Cited by 9 publications

References 5 publications

Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses

Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses

ESR Dating of Barite in Sea-Floor Hydrothermal Sulfide Deposits in the Okinawa Trough

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

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