CO5-1

Study of Earth and Planetary Matters by Thermoluminescence

Department of Applied Physics, Okayama University of
ScienceTL OF ORDINARY CHONDRITES: Induced TL(thermoluminescence), the response of a luminescentphosphor to a laboratory dose of radiation, reflects themineralogy and structure of the phosphor, and provides
valuable information on the metamorphic and thermal
history of meteorites. Especially the sensitivity of theinduced TL is used to determine petrologic subtype of
unequilibrated ordinary chondrites [1]. Natural TL, theluminescence of a sample that has received no irradiationin the laboratory, reflects the thermal history of the meteorite in space and on Earth. Natural TL data thus provide
insights into such topics as the orbits of meteoroids, theeffects of shock heating, and the terrestrial history of meteorites [2]. Usually natural TL properties are applied tofind paired fragments [3-5].
We have measured TLs of 193 Yamato and 136 Asuka
unequilibrated ordinary chondrites [6]. This time wemeasured induced and natural TL properties of thirty
Yamato unequilibrated ordinary chondrites (LL3: 4, L3:
18, H3: 8) from Japanese Antarctic meteorite collection.
Sampling positions of these chondrites were measured byGPS.
PAIRED FRAGMENTS: As reliable pairing approach,
TL properties within large chondrites were analyzed,
taking advantage of the fact that serial samples fromthese meteorites are known to be paired. Then a set of TL
pairing criteria: 1) the natural TL peak height ratios, LT/
HT, should be within 20%; 2) that ratios of raw natu-ral
TL signal (LT) to induced TL signal (TL Sensitivity)
should be within 50%; 3) the TL peak temperatures
should be within 20℃ and peak widths within 10℃ wasproposed [3].
Above pairing criteria were applied to the 30 samples.
Figure 1 shows how to search fragments satisfying thepairing criteria 1) and 2). We found 15 TL potential
paired fragments. . They constructed one H3, three L3,
and one LL3 groups.
LT Intensity/TL Sensitivity (Dhajala=1)

1000
H3

100

L3

50%
20%

LL3

10

Y980135
1

Y980127
0.1
0.01

0.1

LT/HT

1

10

Fig.1. Ratio of LT to TL Sensitivity vs. LT/HT ratio tosearch fragments satisfying the pairing criteria 1) and 2).

採択課題番号 24004

PRIMITIVE ORDINARY CHONDRITES: Most of
the chondrites had TL sensitivities over 0.1 (Dhajala=1),
corresponding to petrologic subtype 3.5-3.9. Three chondrites, Y980465 (H3), Y980576 (H3), and Y980320(LL3) were revealed to be primitive ordinary chondrites,
petrologic subtype 3.2, 3.3 and 3.4-3.5, respectively.
They are not conflicted to olivine heterogeneity as shownin Fig.2. It is particularly significant in understanding thenature of primitive material in the solar system.
10
H3
L3
LL3

1
TL Sensitivity (Dhajala = 1)

K. Ninagawa

0.1
Y980320
Y980576
Y980465

0.01

0.001
1%

10%
Olivine Heterogeneity (C.V.)

Fig.1. Dhajala-normalized TL sensitivity vs. olivine
heterogeneity
RERERENCES:[1] D. W. G. Sears HWDO, Proceedings of Lunar andPlanetary Science, 21 (1991) 493-512.
[2] P. H. Benoit et al., Icarus, 94 (1991) 311-325.
[3] K. Ninagawa HW DO, Antarctic Meteorite Research, 11(1998) 1-17.
[4] K. Ninagawa HW DO, Ant-arctic Meteorite Research, 15(2002) 114-121.
[5] K. Ninagawa HW DO, . Antarctic Meteorite Research 18(2005) 1-16.
[6] K. Ninagawa HWDO., . 35th Symposium on Antarctic
Meteorites (NIPR, Tokyo), (2012) 114-116.

熱ルミネッセンスによる地球惑星物質の研究（岡山理大）蜷川清隆、西戸裕嗣

100%

一般通常

CO5-2

Measurement of Environmental Radioactivity and Heavy Metal in
Seaweed Samples

T. Ohta, T. Kubota1, T. Fujii1 and S. Fukutani1

Faculty of Engineering, Hokkaido University
1
Research Reactor Institute, Kyoto University

INTRODUCTION:
Sequential extraction has been proven to be a useful andpractical technique for the speciation analysis of radionuclides in the soil and sediment samples [1-5]. We extracted 137Cs and 129I from surface soil samples after the
Fukushima NPP accident to estimate impact of humanactivities.
EXPERIMENTS: The two soil samples of depths of
0−2.5cm were reduced by cone and quartering to approximately 10 g. Approximately 10 g of the samples
were used in the sequential-extraction experiment. A solution/sample ratio of 5 (v/w) was used for extraction ineach step (Fraction 1, 2, 3, 4, 5 and residue).
Fraction 1: Ultrapure water was added to the soil sample,
and the sample was shaken for 24 h at room temperature.
The sample was stored overnight. This fraction represents water-soluble species. The remaining solid on thefilter paper was combined with the residue for the leaching in the next step.
Fraction 2: 1 M of NaAc was added to the residue fromFraction 1. The sample was shaken for 12 h at room
temperature and stored overnight. This fraction represents exchangeable species.
Fraction 3: 1-M NaAc−HAc (pH 5) was added to theresidue from Fraction 2, and the sample was shaken for
12 h at room temperature. This fraction represents carbonate-bound species.
Fraction 4: 0.04-M NH2OH・HCl in 25% (v/v) HAc (pH2) was added to the residue from the fraction and stirredin a hot-water bath at 80 °C for 4 h. This fraction represents species associated with solids via chemical-sorption
mechanisms which can be released into the extraction
solution with a weak reducing agent, and they mainly
include species bound to Fe/Mn oxides.
Fraction 5: 30% H2O2 was added to the residue, in which

HNO3 had already been added to adjust the final pH to 2,
and the sample was agitated for 2 h at 85 °C. After the
sample solution was cooled to room temperature, 1.8-M
NH4Ac in 11% HNO3 (v/v) was added, and the extraction
continued for 30 mins at room temperature. This fraction
is associated with organic matter.
After extraction, each solution was separated from thesoil residue by centrifugation at 2000 rpm for 5 mins.
The solution was filtered through a filter paper with apore size of 0.45 µm. After each fraction was stored into
the U-8 vessel, 137Cs was measured by gamma-ray spectrometry (Hokkaido University). I-129 was measured by
AMS (Tokyo University).
RESULTS: The amount of 137Cs leached into water(F1) from the Kanto-loam soil was below the detection
limit. The rate of 137Cs exchange from the two soil samples was less than 1%, with 50–60% of 137Cs remaining
in the residue. Approximately more than 90 % of 137Cs
was adsorbed on organic matter and the residue, while129
I was mainly fixed by Fe-Mn oxidation and organicallybound.

REFERENCES:[1] D. Desideri et al., Speciation of natural and anthropogenic radionuclides in different sea sediment samles. J. Radioanal. Nucl. Chem., 248 (2001) 727–733.
[2] D. Desideri et al., Geochemical partitioning of actinides, 137Cs and 40K in a Tyrrhenian sea sediment
sample: comparison to stable elements. J. Radioanal.
Nucl. Chem., 251 (2002) 37–41.
[3] D.H. Oughton et al., 1992. Radionuclide mobility andbioavailability in Norwegian and Soviet soils. Analyst,
117 (1992) 481–486.
[4] G. Riise et al., A Study on Radionuclide Association
with Soil Components using a Sequential Extraction
Procedure, J. Radioanal. Nucl. Chem., 142, (1990)
531–538.
[5] A. Tessier et al., Sequential extraction procedure forthe speciation of particulate trace metals, Anal.
Chem., 51 (1979) 844–850.

採択課題番号 24013 現世から過去 100 年間の海藻中の環境放射能と重金属類の測定 共同通常
（北大・工学研究院）太田朋子、（京大・原子炉）窪田卓見、福谷 哲、藤井俊行

CO5-3

Radiometric Dating for Paleoenvironmental Study of East Asia

N. Hasebe, Y. Nakano1 and M. Ogata1
Institute of Nature and Environmental Technology, Kanazawa University
1
Graduate School of Natural Science and Technology,
Kanazawa University
INTRODUCTION: Luminescence dating observes thenatural accumulated radiation damage caused by radioisotopes such as U and Th as the form of glow after stimulation by heating or lightening. Thermally stimulated
luminescence from calcite shows strong red emission [1].
However, calcites are less popular in thermoluminescence dating due to their variability in glow curves
against temperatures and in alpha effectiveness [2,3].
To investigate luminescence characteristics of calcite,
samples were artificially irradiated by alpha particles andgamma rays, and their luminescence intensities were calibrated against luminescence by x-ray, which is used tomake a dose response curve to calculate equivalent accumulated doses. Stability of luminescence sites was also
investigated by tracking the change in luminescence signals before and after the storage. For above mentioned
experiments, calcite formed by precipitation through fluid
circulation within ophiolite suits from Philippines wasanalysed. To test luminescence signals were reset at thetime of calcite formation, luminescence from synthetic
calcites were measured.
RESULT<gamma vs x-ray>: Glow curves of samples
irradiated with gamma or x-rays show a common peak at
250°C (Fig. 1). However, peaks at lower temperature
ranges are different; 80°C for x-ray but 140°C for gamma.
Therefore, to omit the contribution of these low temperature peaks, samples are preheated at 200°C for 180 seconds. This process make a 250°C peak sift to 280°C. After the gamma ray irradiation of 134.2 Gy at the 60Co
gamma irradiation facility at Kyoto University Research
Reactor, luminescence signals at the 280°C peak are calibrated by the dose response curve obtained by the x-ray
irradiation. The calculated result was only 27% of thegiven gamma dose, indicating the different sample sensitivity against gamma and x-ray irradiations.
RESULT<alpha vs x-ray>: Alpha particles from 241Am(5.4MeV) were irradiated to sample. First, number ofalpha emission per unit area per a minute was estimatedby the alpha track counting recorded on CR39 plastic
sheet. Then luminescence intensity after alpha irradiation
was calibrated against dose response curve formed by
x-ray irradiation. Luminescence emission by alpha irradiation show peaks at temperature of ~280°C (note: after
preheating at 200°C), same with x-ray or gamma-ray
induced luminescence. As a result, the estimated dose
was 76% of a given dose.

RESULT<fading>: For feldspar Infrared stimulated luminescence, fading of luminescence signal during thestorage is a significant problem for its use in geochronology. To investigate the long-term stability of calcite
luminescence, signals were measured before and after the
storage and compared. Storage time was set as 24 hours.
The results show no significant signal loss during thestorage.
RESULT<synthetic calcite>: To make sure that luminescence is only caused by the exposure to radiation,
luminescence measurement of newly synthetic calcite in
the laboratory was carried out. Synthetic calcite shows avery small signal equivalent to ~10Gy at the temperatureof 280°C. For very young samples, this value is not ignorable.
Summary: Calcite TL signal shows a potential to provide radiometric ages. When naturally accumulated
dose is estimated as a comparison against x-ray induced
luminescence, differential behavior between x-ray andnaturally occurring radiations must be addressed. Emission of luminescence from 0-age sample suggests theimportance of “background (non-radiation induced luminescence)” correction.
REFERENCES:[1] A. Inagaki et al., J. Geol Soc. Japan 116 (2010)
XIX-XX[2] N. M. Johnson, J. Sed. Petrol. 30 (1960) 305-313[3] M. Gaft et al., Am. Mineral. 93 (2008) 158-167

-ray
x-ray (90Gy)
x-ray (240Gy)

Fig. 1 Luminescence glow curves after gamma or x-rays
irradiations.

採択課題番号 24017
東アジアにおける古環境推定のための放射年代測定（金沢大・環日本海域セ）長谷部徳子（金沢大院・自然）中野靖幸、小形学

一般通常CO5-4Behavior of Cesium during the Melting of Model Soil

M. Takaoka, S. Yamaguchi1, K. Shiota1, K. Oshita1 andS. Fukutani2of the standard sample (NIST SRM 1633c: Coal fly ash,certified Cs level 9.36mg/kg [1]).

Department of Environmental Engineering, Graduate
School of Engineering, Kyoto University
1
Department of Environmental Engineering, Graduate
School of Engineering, Kyoto University
2
Research Reactor Institute, Kyoto University

RESULTS: The Cs concentrations in the samples areshown in Table 1. The Cs in the model soil was concentrated in the melting fly ash after the melting treatment.
The Cs concentration in the melting slag was 1/30 to
1/100 lower than that in the melting fly ash.
The Cs concentrations were lower in slag derived fromthe model soil having a higher Cl concentration. It wasthought that chloride volatilization promoted the settlement of Cs in the melting fly ash. The boiling points ofmost Cs compounds range from 951 to 1568K, which islower than the melting temperature used (1773K) [2], andthere was little difference in the Cs concentration among
the melting fly ash samples. Future laboratory-scalemelting tests with mass balance estimation are needed.

INTRODUCTION: After the 2011 Tōhoku earthquake
and tsunami, contamination by the radioisotopes 134Cs
and 137Cs released from the Fukushima Daiichi Nuclear
Power Plant was spread widely in Fukushima Prefecture
and the Kanto region of Japan. The contaminated property included land, houses, rubble, trees, agricultural crops,
soil, and sewage sludge.
In this study, the stable isotope 133Cs was added to model
soil, and the concentrations and behaviors of 133Cs were
estimated in a pilot-scale melting of model soil, as is used
to decontaminate soil. First, the 133Cs concentrations invarious melting residues of model soils were investigatedusing instrumental neutron activation analysis (INAA).
Then, the decontamination of soils by melting was estimated from an analysis of 133Cs and the composition of
the model soils.
EXPERIMENTS: The model soil was an 85:15 mixtureof decomposed granite soil and bentonite, to which anaqueous solution of Cs2CO3 was added. In addition,
Ca(OH)2 and Fe2O3 were added to control the basicity ofthe model soil, and CaCl2 was added to control the Cl
concentration.
Two model soils with different Cl concentrations weremelted continuously for about 24 h at approximately
1773K. The melting fly ash and slag were sampled 4, 8,
18, and 22 h after the experiment started.
The Cs concentration in the samples was analyzed by
INAA. The 50－100 mg of dried samples were packed
into the double polyethylene bag and outside bag. Two
samples were prepared per one kind of sample. Thermal
neutron irradiation to the samples was carried out using
by pneumatic transport pipe (Irradiation hole: Pn-2) at
Kyoto University Research Reactor Institute. The irradiation time was 60 min, and after that, the samples werecooled down during 1 month. Radioactivated Cs in samples was analyzed by the germanium semiconductor detector with the 4096 channel peak analyzer. The measurement time was 7,200 sec. The energy with the highest
peak, 795.8keV, was selected as the energy of Cs for
gamma-ray spectrometry. The calculation of radioactivityof samples was carried out using by Fitz peaks (JF Computing Services). Cs concentration in each sample wasdetermined by the comparison method using 25－50mg

採択課題番号24019

Table 1. Cs concentration of some media on melting test
Item
Melting fly ash 1-1
Melting fly ash 1-2
Melting fly ash 2-1
Melting fly ash 2-2
Melting fly ash 3-1
Melting fly ash 3-2
Melting fly ash 4-1
Melting fly ash 4-2
Slag 1-1
Slag 1-2
Slag 2-1
Slag 2-2
Slag 3-1
Slag 3-2
Slag 4-1
Slag 4-2
Model soil 1-1
Model soil 1-2
Model soil 2-1
Model soil 2-2
Model soil 3-1
Model soil 3-2
Model soil 4-1
Model soil 4-2

Cs(mg/kg)
INAA 795.8KeV
5278
6761
8465
9093
6788
6356
5851
5524
166.9
181.5
135.5
131.6
100.3
102.6
87.35
86.79
1067
1156
1366
1292
1043
1053
1450
1464

No.1‐2: Model soil with low Cl conc.,
No.3‐4: Model soil with high Cl conc.
REFERENCES:[1] NIST SRM 1633c: https://www-s.nist.gov/srmors/view_detail.cfm?srm=1633C.
[2] C.Yaws: Chemical Properties Handbook, Physical
Thermodynamic, Environmental, Transport, Safety, andHealth Related Properties for Organic and Inorganic
Chemicals, McGraw-Hill NY 1999.

廃棄物焼却炉からの微小粒子の排出にともなう重金属
共同通常
および貴金属の挙動に関する研究（京大院・工）高岡 昌輝、米田 稔、大下 和徹、松井 康人、塩田 憲司、山口 修史、
辻本悠真、中村尊郁、劉 露、西岡 和久（京大・原子炉）福谷 哲

CO5-5 Foliar Uptake and Volatilization of Iodine Applied to a Leaf Surface in Small Drops
H. Tsukada, H. Kawabata, M. Yanai, N. Akata,
H. Kakiuchi, A. Takeda, S. Fukutani1 and T. Takahashi1
Department of Radioecology, Institute for Environmental
Sciences
1
Research Reactor Institute, Kyoto University
INTRODUCTION: Foliar uptake of radionuclides is
an important process that can be used to estimate theirconcentrations in plants. Iodine is an essential element foranimals and it is well known that iodine is needed for thesynthesis of thyroid hormones and iodine deficiency induces thyroid diseases. Radioiodine was the major radionuclide released from the Fukushima Daiichi Nuclear
Power Plants after the accident in March 2011 because of
its high fission yield and volatility. Therefore, theknowledge on the transfer of iodine necessitates estimating internal radiation exposure through agricultural foodingestion. In the present study, foliar uptake of iodine
applied in small drops to a leaf surface and its volatilization from the leaf surface were determined by a laboratory experiment.
EXPERIMENTS: Orchard grass (Dactylis glomerata
L.) was cultivated hydroponically in an artificial climate
chamber (air temperature, 20°C; relative humidity, 70%;
light intensity, 30 klx; light length, 12 h). After applying
fifty 3 μL drops of NaI solution (200 mg I L-1) on the leaf
surface, the sample was closed in a transparent acrylic
box. Air excluding iodine was ventilated at the flow rateof 18 L min-1 and volatile iodine released from the leaf
surface was collected and divided into particulate, inorganic and organic iodine. Particulate iodine was collectedwith fluoropore AF07P filters (Sumitomo Electric, 47mm ϕ). Inorganic gaseous iodine was collected with threecellulose filters (Whatman 41, 47 mm ϕ) impregnatedwith 1 M LiOH in a 10% glycerol water mixture[1] andorganic iodine was collected with 6 activated carbon paper filters (STV-2465, Kynol, 47 mm ϕ). After cultivating
24 h in the box, the leaf sample was washed with a surfactant solution (0.1 % Triton X-100 at pH 9). The leaf

and root samples were separated and dried at 50°C andpulverized with a stainless steel cutter/blender. Iodine in
the plant samples was extracted with tetramethyl ammonium hydroxide. The concentration of iodine in the solution samples was measured with ICP-MS. The filter samples were sealed separately in a polyethylene bag, andanalyzed by neutron activation analysis using the KUR
reactor (Pn-3) at a thermal neutron flux rate of 4.9 ×
1016 n m-2 s-1 for 150 s.
RESULTS: Table 1 shows the percentage distributionof iodine in the grass sample, which was separated into
washing solution, leaf, and root, at 24 h after the application of small drops of a NaI solution to the leaf surface.
The distribution of volatilized iodine fractions such as
particulate, inorganic and organic iodine are also indicated in Table 1. The yields of applied iodine, that is, thesum of the amount in the washing solution, plant andvolatile fractions, were 92 and 95%. The residue of iodine may have adsorbed on the surface in the box because the plant was kept in the closed box during the experiment. The volatile amount of iodine was only
0.1-0.2 % of the applied iodine which was in the inorganic fraction. It has been reported that the chemical
forms of iodine collected as inorganic fraction were I2, HI,
HOI, and IO radicals. The percentage distribution of iodine in the washing solution, which was on the leaves,
was about 5 %, whereas that inside the leaf was approximately 90%. This suggests that most of the iodide appliedwith small drops is immediately transferred from the leaf
surface. However, the percentage distribution of iodine in
the root was a negligibly small value, suggesting that thetranslocation of iodine from leaf to root was slow. Morestudies on foliar uptake and volatilization of iodine by
applying iodine in aerosol and gaseous forms will be required.
REFERENCES:[1] K.A. Rahn, R.D. Borys, R.A. Duce, Science, 192(1976) 549

Table 1. Percentage distribution of iodine in washing solution, leaf, and root and in volatilized iodine fractions following the foliar application of small drops of a NaI solution
Sample No.

Plant （％）

Volatilization （％）

Yield （％）

Washing
solution

Leaf

Root

Particle

Inorganicgas

Organic gas

OGLD_1d_a

7.4

84.4

0.2

－

0.2

－

92

OGLD_1d_b

4.5

90.3

0.2

－

0.1

－

95

Mean

5.9

87.3

0.2

－

0.2

－

94

採択課題番号 24024
環境中におけるヨウ素の移行動態に関する研究（公財環境研）塚田祥文，川端一史，赤田尚史，柿内秀樹，武田晃（京都大・原子炉）福谷哲，高橋知之

共同通常CO5-6 Neutron Activation Analysis of Elemental Concentrations in Atmospheric Aerosols
at Sakai,Osaka
N. Ito, A. Mizohata, R. Okumura1 and Y. IInuma1

Radiation Research Center, Osaka Prefecture University,
1Research Reactor Institute, Kyoto University

concentration to soil particle) are shown in Fig.2. The
element for which non natural effect is high (ratios in
Fig2 >10) are Cl(Sea Salt), Cr, Zn, As, Br, Mo, Sb, W.

21 elements in atmospheric aerosols daily sampled at
Osaka Prefecture University, Sakai, Osaka were analyzed
by Neutron Activation Analysis. Average ofconcentrations in these elements were determined. Someof the elements have the effects from the non natural
aerosols originated from industry or vehicle.
Samples
The atmospheric aerosols were daily sampled at Osaka
Prefecture University, Sakai, Osaka. Table1 lists the
sampling condition. The samples collected on January
and February in 2007 were analyzed .
Table1 Sampling conditions of the aerosol particles.
Conditions
Description
Location

Osaka Prefecture University, Sakai Osaka

Period24 hours

Filter25mmΦ membrane (Advantec A100)

Particle Separation

Non-Separation(Total particle)
Neutron Activation Analysis
2 way of Neutron irradiation and measurement weredone for each sample. One way is short irradiation for
short lived activated element and the other is longirradiation for long lived activated element. Elements foreach irradiation way are listed on Table2.
Table 2. Irradiation way and elements for each
irradiation.
Irradiation Way

Fig. 1. Average of each element(Obs_Aerosol) andestimated concentration of soil particle(Est_Soil_PM).

Elements

Short (120sec in PN1)

Al, Cl,Ca,Ti,V, Mn

Long(7200sec in PN2)

Na, K, Cr, Fe,
Zn,As,Br,Rb,Mo,Sb,La, Ce,Sm,W

ResultAverages of each element are shown in Fig.1 andestimated concentrations of soil particle are shown
together. These estimation have been carried out using
concentration of Al and general rations of each element
in soil. If the observation concentration is clearly higher
than estimated soil particle concentration, for thiselement non natural effect, other than soil, is main
contribution for the element. Rations (observation
Obs_Aerosol/Est_Soil_PM
Fig. 2. Ratio of average concentratio (Obs_Aerosol) to
estimated concentration of soil particle(Est_Soil_PM).

採択課題番号 24032
大気エアロゾル粒子のキャラクタリゼーション、共同通常(大阪府大・地域連携 )伊藤憲男、溝畑 朗、 (京大・原子炉 )奥村 良、飯沼勇人

CO5-7

Evaluation of Hypoxia at Dredged Trenches in Tokyo Bay
by Determination of Fe and Mn in the Sediments

T. Yamagata, K. Shozugawa, R. Okumura1, K. Takamiya1
and M. Matsuo
Graduate School of Arts and Sciences, The University ofTokyo
1
Research Reactor Institute, Kyoto University

INTRODUCTION: Hypoxia is water mass contained little dissolved oxygen (DO), which has influenced ecosystems and fisheries [1]. At the seabed in Tokyo Bay, large-scale dredging operations had been donein 1970s. In particular, the dredged trenches off Makuhari
have the maximum area and depth. In dredged trenches
strong hypoxia has been observed in summer, and the
hypoxia has disappeared in winter. But the influence ofdredged trenches on hypoxia is not revealed yet. Therefore, it is important to estimate the interannual variationsof hypoxia by analyzing sediments.
To evaluate the sedimentary environment such as redox conditions, we have been studying the method using
Fe and Mn, because their various chemical states on
Eh-pH diagrams have become clear [2], and they are
expected to take the chemical states corresponding to theredox conditions of seawater. We reported the concentrations of Fe and Mn in sediments from the Makuhari
dredged trenches in summer [3]. In this study, sedimentcores were collected in winter, and the concentrations ofFe and Mn were analyzed by instrumental neutron activation analysis (INAA).
EXPERIMENTS: The sediment samples were collected at two dredged trenches (water depth 24.7 m and18.0 m) and reference site (non-dredged seabed, water
depth 9.7 m) off Makuhari in Tokyo Bay on February
2012. Sediments were collected by a core sampler at eachpoint. Water quality data were also obtained by a multichannel water quality meter and an oxidation-reduction
potentiometer. All cores were cut in the vertical direction
at 0.6 - 3.0 cm intervals after freezing. The divided samples were desalted by using an ultrasonic cleaner and acentrifuge, and then they were freeze-dried.
Approximately 30 mg of desalted and freeze-dried
sediments were packed in double polyethylene film bags
to perform INAA. All samples were irradiated at thepneumatic tube, Kyoto University Reactor (KUR). Twotypes of gamma-ray measurement were carried out corresponding to half-lives of elements. For analysis of Mn,

samples were irradiated for 10 seconds at 1 MW, andthen gamma-ray was measured for 600 seconds by Ge
detector after 600 seconds cooling. Regarding Fe, samples were irradiated for 20 minutes at 1 MW or 4 minutes
at 5 MW, and the measurement time of gamma-ray wasfor 9000 seconds after 3 weeks cooling.
RESULTS: The DO in the seawater at dredged trenches and reference site (non-dredged area) indicated thesimilar vertical distribution at each point. From the surface, the DO decreased gradually. At the bottom, the DO
became 8 - 9 mg/L at every site. And hypoxia has notbeen observed in Tokyo Bay in the winter of 2012.
Figure 1 shows depth profiles of Fe and Mn in thesedi-ments collected at both dredged and non-dredged
area. At every site, concentrations of both elements were
almost constant at the surface. On the other hand, we
mentioned that concentrations of both elements decreased
near the surface at dredged trenches in the summer of2011 [3]. It is well-known fact that the concentrations ofFe and Mn in sediments increase when condition ofseawater is oxi-dative. On the other hand, theconcentrations decrease due to eluviations of Fe2+ andMn2+ when condition of seawater is reductive likehypoxia. The results indicate that Fe2+ and Mn2+ wereoxidized and precipitated under the oxic condition in thewinter of 2012.

Fig. 1. Depth profiles of Fe (left) and Mn (right) in thesediments.
REFERENCES:[1] R.J. Diaz and R. Rosenberg, Science, 321 (2008),
926-929.
[2] D.G. Brookins, in Eh-ph diagrams for geochemistry(Springer-Verlag, 1988).
[3] K. Shozugawa et al., KURRI Prog. Rep., 2011 (2012),
252.

採択課題番号 24049
汽水域および沿岸域堆積物の放射化分析
共同通常（東大・大学院総合）松尾基之、小豆川勝見、山形武広、小森昌史、下元類、陳品彧、添盛晃久、
田畑昇人（京大・原子炉）高宮幸一、奥村良CO5-8The Possibility of Radionuclide Detection in Atmospheric Precipitation
far from Fukushima

S. Sakurai and H. Yashima1
Department of Physics, Niigata University
1
Research Reactor Institute, Kyoto University
INTRODUCTION: The release of artificial radionuclides occurred into the atomosphere following Fukushima Daiichi Nuclear Power Station in March 2011.
This accident caused the contamination of terrestrial andaquatic systems by radiocesium in the eastern Japan,
mainly Kanto and Tohoku districts. Since the nuclear
accident, many reports on the behavior of radionuclides
in the environmental in these districts have been published. It is important to make a widespread investigation
into the deposit of radioactive materials in Japan.
In this study, we monitored dry and wet deposition of137
Cs in Sakai city in Kansai district, the western Japan toelucidate the possibility of radionuclide detection in atmospheric precipitation in Sakai city, Osaka far from
Fukushima.
EXPERIMENTS: The monitoring started in December 2011 at the rooftop of Osaka Prefecture University located in Sakai City, Osaka. This monitoring site isapproximately 700 km far from Fukushima Daiichi Nuclear Power Station.
A porcelain enamel bat (0.35 m × 0.45 m) is set forcollection of each of dry and wet deposition. The former
was collected for about 14-21 days, the latter was collected every rain events (>1mm). Dry deposition in thebat was rinsed with 100 mL of 0.6% nitric acid and distilled water. The liquid sample obtained was dried up
using an electromagnetic induction heater and evaporation lamps followed by measuring radioactivity.
The amount of 137Cs in the dry and wet deposition
was measured using gamma-ray spectrometry with a Ge
semiconductor detector (SEIKO EG and G Co., Ltd.,Tokyo, Japan) coupled to a multi-channel analyzer(SEIKO EG and G Co., Ltd., Tokyo, Japan). The meas-

urement time ranged from 1 hour to 10 days by trial
and error.
RESULTS: Table 1 shows the 137Cs activities of dry
deposit during the monitoring period. The activities of137
Cs are below 1 Bq in all the dry deposit samples aswell as those of wet deposit (data not shown). In general,
both dry and wet deposit of radioactive materials in thestudied area was little detected during the monitoring

採択課題番号 24055

period. Ito reported that fallout of major concerning radionuclides 131I, 134Cs and 137Cs in the area tested nearby
the studied site was detected for one and half months
after the nuclear accident, but that thereafter radioactivity
concentration was under limit of detection [1]. The result
obtained in our study was in agreement with those results
reported. The risk of radionuclides from the Fukushima
accident is probably very small in Sakai city.
The Fukushima Nuclear Accident is not brought to theend. Contamination of soil, water and air by radioactive
materials potentially occurs following an expected incident. Moreover, there also is a possibility of the releaseof radionuclides from the nearby waste treatment station
due to insufficient surveying of radiation measurement ofwastes and/or improper treatment operation. It is important to continuously monitor the radiation and thepresence of radionuclides with respect to risk of environment and human health.
Table 1 Radioactivities in dry deposit samples during
test period
Collecting Duration
Radioactivity (Bq)0.046
2011/12/23-2012/1/5

2012/1/6-23
2012/1/24-2/10
2012/2/11-/3/1
2012/3/2-3/21
2012/4/26-5/16
2012/5/17-6/3
2012/6/4-2012/6/22
2012/7/18-8/1
2012/9/12-10/5
2012/10/27-11/14
2012/11/15-12/4
2012/12/30-2012/1/20

2013/1/21-2/14

0.016
0.009
0
0.004
0.002
0.003
0.002
0.002
0.005
0.005
0.006
0.008
0.003

Acknowledgements:
This work was supported by Grant for Environmental
Research Projects from the Sumitomo Foundation.
REFERENCES:[1] N. Ito., Annual bulletin of Radiation Research Centerof Osaka Prefecture University., (2012), p23 (in Japanese).

発生源から遠方における大気降下物を介した放射性物質の検出と環境影響評価（大阪府大・生命環境）櫻井伸治（京大・原子炉）八島浩

共同通常

CO5-9 Study on Thermal History of Rock Sample Based on Fission Track Dating Method
H. Ohira and A. Takasu
Department of Geoscience, Shimane University
INTRODUCTION: Fission track age dating was applied for the Tsukinuno bentonite mine to examine depositional ages of bentonite, and its relation with igneousrocks and tuffs which are distributed in surrounding area.
The Tsukinuno bentonite deposit is located in central
Yamagata Prefecture and high quality Tsukinuno bentonite is used in the foundry and civil engineering fields, andfor cat-litter. The bentonite mainly hosted in mudstone iscomposed of 31 bentonite layers and each bentonite layer
is assigned a number from the bottom to top (No.1 to No.
31). The bentonite is considered to have formed by diagenetic and low temperature hydrothermal alteration.
Parent rocks of bentonite are generally considered to be
tuffaceous rocks which contained abundant glass shards.
However, based on chemical compositions including
REE analysis, parent rocks of the Tsukinuno bentonite
layers were considered to be genetically related to surrounding tuffs, volcanic rocks and granitic rocks [1]. The
formation age was first reported by fission-track and
K-Ar methods, but the ages vary from 13 to 21 Ma [2].
More recent microfossil and fission-track analysis of afew samples from mine tunnel gives ages from 9.1 and9.6 Ma [1]. This inconsistency may be due to contamination by older detrital zircon or clay flakes.
EXPERIMENTS: Four bentonite layers (No.2, No.13
and No.29 and No.31) were collected from the Tsukinuno
mine and tuffs (Ishikura tuff (IK-tuff)), volcanic rocks(Mazawagawa dacite (MZ-dacite)) and granitic rocks(Mitate Granite (MT-granite)) were collected from
northeastern part of the Tsukinuno mine. Zircon grains
were separated by conventional magnetic and heavy liquid separation techniques. Zircons were mounted in PFA
Teflon, and then polished to reveal a complete internalsurface. Zircons were etched in a NaOH-KOH eutectic
melt at 225˚C [3] for 24-32 hours. Samples were irradiated at pneumatic tube of graphite facility (Tc-pn) of
Kyoto University Reactor (KUR). After irradiation, external detectors (mica) were etched in 46% HF at 25˚C
for 6-7 minutes (for mineral mounts) and for 20-50min(for NIST-SRM612). FT densities were measured at
1000× magnification with a dry objective. The zeta values used were 367.1±4.1 and ages were calculated using
the Trackkey program [4].

RESULTS: Results are shown in Table 1. FT ages ofbentonite layers were 10.4Ma, 9.6Ma, 9.5Ma and 9.6Ma,
respectively. Almost analyses (except for No.31) passed
χ2 test at the 5% criterion [5]. This means that the variability in the track count data is limited to the inherent
variability in radiometric decay process, and affect of
detrital grains supplied from various parent rocks is relatively low. The obtained ages 10.4 - 9.6Ma probably indicate depositional ages of the bentonite layers. Tuff andigneous rocks collected at surrounding area of the mineshow variable ages, 9.8Ma (IK-tuff), 9.2Ma (MZ-dacite)
and 46.7Ma (MT-granite). IK-tuff and MZ-dacite arepossibly correlated with bentonite layers. On the contrary,MT-granite (46.7Ma) show significantly older age, suggesting that the granite is not parent rock of the bentonite
layers. K-Ar age of biotite of the MT-granite has beenreported to be 9.5Ma [1]. The inconsistency between FTage (46.7Ma) and K-Ar biotite age (9.5Ma) is probably
due to difference in thermal stability of each dating system. FT method is more stable for a certain type of hydrothermal alteration.
Table 1. Fission track analytical data.
Pχ2
Age
ρs
ρi
ρd
(％)
(1σ)
(Ns)
(Ni)
(Nd)
No.31
3.514
14.67
1.4
2.174
9.6
Bentonite(1395)(5822)(7178)
(0.3)
No.29
30
0.794
3.331
99.5
2.174
9.5
Bentonite( 711)(2981)(7164)
(0.4)
No.13
42
3.002
10.57
98.0
1.832
9.6
Bentonite(1840)(6482)(7259)
(0.3)
No.2
30
1.615
6.197
94.7
2.174
10.4
Bentonite(1187)(4555)(7171)
(0.4)
IK34
1.827
6.298
49.1
1.832
9.8
tuff
(1498)(5164)(7259)
(0.3)
MZ33
2.574
9.417
39.9
1.832
9.2
dacite(1524)(5575)(7259)
(0.3)
MT12
5.361
3.855
28.0
1.832
46.7
Granite(1292)( 929)(7259)(2.1)
ρ=track density; N=total number of tracks counted; s for spontaneous, i for induced and d for dosimeter; P (χ2) =probability of obtaining χ2 value for v degrees
of freedom (where v=number of crystals-1) [5].
Sample

No.
Crys
23

REFERENCES:[1] Sato Y. et al., 2011, Abstract of 61st Annual meetingof Resource Geology of Japan (P-32) (in Japanese).
[2] Ito K. et al., 1999, Clay science, 38, 181-187 (inJapanese with English abstract).
[3] Gleadow A.J.W. et al., 1976, Earth and Planetary
Science Letter, 33, 273-276.
[4] Dunkl I., 2002, Computers and Geosciences, 28,
3–12.
[5] Galbraith R. F., 1981, Mathematical Geology, 13,471-488.

採択課題番号 24061 フィッション・トラック年代測定法による岩石の熱履歴解明に関する研究 一般通常
（島根大・総合理工）大平寛人、高須 晃

CO5-10Determination of Abundance of Rare Metal Elements in the Currently
Forming Antimony Ore Deposits of Kagoshima Bay by INAA Techniques

T. Yamanaka, T. Tomoki, J. Ishibashi1, H. Inoue1,
T. Noguchi2, R. Okumura3 and K. Takamiya3
Faculty of Science, Okayama University
Faculty of Science, Kyushu University
2
Marine Technology and Engineering Center, Japan
Agency for Marine-Earth Science and Technology
3
Research Reactor Institute, Kyoto University
1

INTRODUCTION: To meet recent increased demand
for rare metal elements as mineral resources, high sensitive multi-element analysis becomes more important as
geochemical tools for mineral exploration. Instrumental
neutron activation analysis (INAA) has the advantage of
non-destructive analysis and is free from problems thatconcentrate of a specific element is often included inresidue during acid dissolution. Previous studies havedemonstrated that INAA enables rapid abundance determination for multi elements in ore samples collectedfrom active seafloor hydrothermal fields that consist ofvariety of sulfide/sulfate/silicate minerals [1,2]. In order
to extend the range of application of this technique, westarted preliminary studies using hydrothermally alteredsediment and antimony sulfide ore deposits.
EXPERIMENTS: Two groups of natural samples
were provided for this study. One was antimony sulfide
ore deposits collected by ROV/HyperDolphin, and theother was hydrothermal altered sediment collected bypiston-corer within an active hydrothermal field inWakamiko submarine crater in the Kagoshima Bay.
For analysis of long-lived nuclides (110mAg, 59Fe, 203Hg,
124
Sb, 65Zn, 134Cs) and mid-lived nuclides (76As, 198Au,
131Ba), samples were irradiated at Pn-1 (thermal neutron
flux = 3.86×1012 n/cm2/sec at 1 MW) for 3 hours, and the
gamma ray activity was measured for 3 hours after
around 30 days cooling and for 50 minutes after 3-10
days cooling. For analysis of short-lived nuclides (66Cu,
56
Mn, 115In, 52V, 83Se), samples were irradiated at Pn-3
(thermal neutron flux = 4.86× 1012 n/cm2/sec at 1 MW)
for 1 minute, and the gamma ray activity was measured
for 5 minutes after 10-30 minutes cooling. Concentrationof each element was calculated by comparison of gamma
ray intensity between the sample and standard materials;
Na for short-lived nuclides measurement and Co for midand long-lived nuclides measurement.
RESULTS: Indium (In), selenium (Se), vanadium (V),manganese (Mn), and gold (Au) were detected by NAA
in addition to arsenic (As), antimony (Sb) and mercury(Hg), which have been previously reported anomalouscondensation in this area. Concentrations of As, Sb andAu show obvious positive correlation in the sulfide ore
deposits (Figs. 1 and 2, sample# 1363 ~1366). On theother hand, correlation of As and Au relative to Sb in thehydrothermal altered sediments (Figs. 1 and 2, sample#
P3 ~ P5) was not clear.
As, Sb and Hg are expected to precipitate directly fromthe hydrothermal fluid mostly as sulfide minerals, whilehydrothermal alteration of sediments may be occurred
relatively lower temperature condition, suggesting thatremained As and Hg in the hydrothermal fluid continue
to precipitate into the sediment layer and Sb and Au is
already depleted in the fluid.
Relatively high concentration of Mn, V and In were observed in the sediment layer where hydrothermal alteration is not obvious. It may suggest those elements are
precipitated from the bottom seawater containing hydrothermal components once emitted from the vents undersuitable physicochemical condition.
As demonstrated above, INAA provided useful information for discussion on potential of mineral resourcesin a seafloor hydrothermal field.

Fig. 1 Relation of Antimony and arsenic concentrations in theore deposits (sample# 1363 ~ 1366) and hydrothermal alteredsediment (sample# P3 ~ P5)

Fig. 2 Relation of Antimony and gold concentrations in theore deposits (sample# 1363 ~ 1366) and hydrothermal alteredsediment (sample# P3 ~ P5)

REFERENCES:[1] T. Noguchi et al., Geochem. J. 41, 141-148 (2007)[2] T. Noguchi et al., J. Mineral. Petrol. Sci., 106, 26-35(2011)

採択課題番号 24062
鹿児島湾熱水系アンチモン鉱床中の微量元素組成の解明
共同通常（京大・原子炉）奥村良、高宮幸一（岡山大・理）山中寿朗、柏村朋紀（九州大・理）石橋純一郎、
井上博靖（JAMSTEC・海洋工学センター）野口拓郎

CO5-11 Determination of Abundance of Rare Metal Elements in Seafloor Hydrothermal
Ore Deposits by INAA Techniques-2: Determination of Indium Content
J. Ishibashi, M. Nagahara, H. Inoue, K. Nagatomi,
R. Okumura1 and K. Takamiya1
Faculty of Science, Kyushu University
Research Reactor Institute, Kyoto University

1

INTRODUCTION: To meet recent increased demand
for rare metal elements as mineral resources, high sensitive multi-element analysis becomes more important as
geochemical tools for mineral exploration. Instrumental
neutron activation analysis (INAA) has the advantage of
non-destructive analysis and eliminates possible problems that concentrate of a specific element is often included in minerals poorly soluble during acid digestion.
In order to extend the range of application of this technique, we have conducted preliminary studies using ore
deposit samples collected from active seafloor hydrothermal fields. Here, we report evaluation for quantification of indium with INAA. Indium is included in ore deposits as a trace element which does not form a specificsulfide mineral. Indium content in ore deposits is usually
ppm to sub-ppm order.
EXPERIMENTS: As demonstrated in previous studies[1,2], 115In that is the dominant isotope of indium (natural
isotopic abundance is 95.7%) has a large neutron crosssection for a nuclear reaction to form 116mIn. Since a halflife of 116mIn is 54.1 minute, we applied an analyticalscheme designed for short-lived nuclides to the quantification. Samples were irradiated at Pn-3 (thermal neutron
flux = 4.86× 1012 n/cm2/sec at 1 MW) for 2 minutes, andthe gamma ray activity was measured for 5 minutes after
7-30 minutes cooling. Spectra of 66Cu and 56Mn were also
quantified during the same analytical scheme. Content ofeach nuclide was calculated by comparison of gamma rayintensities between samples and standard materials whichcontains known content of Na and Mn.

Fig. 1 A gamma ray spectrum of CCU-1d (the content ofindium was reported as 7.0 ppm). The irradiation time was
120 seconds, cooling time was 1061 seconds, and measurement time was 300 seconds.

RESULTS: In order to evaluate analytical accuracy, we
conducted a series of analyses for “Certified Reference
Materials” provided by Natural Resource Canada [3]. Fig.
1 shows a gamma ray spectrum of CCU-1d which indium
content was reported as 7.0 pppm. As shown in this figure, three dominant peaks of 116mIn (at 416.9 kev, 1097.3
kev and 1293.6 kev) were identified. For this sample, thepeak area of 116mIn at 1097.3 kev was calculated with arelative statistical error of less than 5%. On the other
hand, during analysis for WMS-1a which indicum content was reported as 0.2 ppm, it was difficult to obtainenough intensity of the spectrum of 116mIn under the same
analytical scheme. From these results, we may estimate
the lower limit of indium qunatification as an order of 1
ppm for sulfide ore deposit samples. This level is about
one order small compared with ICP-MS analysis.
Table 1. Analytical results of Certified Reference Materials
provided by Natural Resources Canada. Numbers enclosed inparantheses indicates informational values (for In), provisional
values (for Mn and Cu of WMS-1a) and certified values (forMn and Cu of CCU-1d).
In (ppm)

Mn (ppm)Cu (wt%)CCU-1d
run 1
run 2

(7.0)
7.4 ± 0.3
6.5 ± 0.3

(99.4 ± 4.4)
84 ± 496 ± 5(23.9 ± 0.3)
15.0 ± 0.1
14.9 ± 0.1

WMS-1a
run 1
run 2

(0.2)
0.21 ± 0.07n.d.

(600 ± 70)
619 ± 6430 ± 8(1.40 ± 0.02)
0.92 ± 0.04
0.64 ± 0.02

Table 1 compiles results of the series of analyses for the
Certified Reference Materials, CCU-1d and WMA-1a.
Results of two runs agreed within a factor of about 1.5.
Although this reproducibility was not so good, it would
be enough for our original purpose to find anomalousenrichment of a specific element. In fact, we identified afew ore deposits showed anomalously high content ofindium (from 20 to 200 ppm) among the samples collected from active seafloor hydrothermal fields in the
Suiyo Seamount.
REFERENCES:[1] M. Ebihara, A. Nemoto, H. Akaiwa, Anal. Sci. 4,
169-173 (1988)[2] G. Meyer et al., J. Radio. Nucl. Chem., 244, 583-587(2000)[3]
http://www.nrcan.gc.ca/minerals-metals/technology/3847

採択課題番号 24065 沖縄トラフ現世熱水鉱床におけるレアメタルの探索
共同通常（九州大・理）石橋純一郎、長原正人、井上博靖、永富健太郎（京大・原子炉）奥村良、高宮幸一

CO5-1240

Ar/39Ar Age of Volcanic Tuffs in the Eastern Africa II

H. Hyodo and T. Itaya

50

Research Institute of Natural Sciences,
Okayama University of Science

RESULTS: An example of age spectra of feldspars fromstepwise heating experiments is shown in Fig. 1. The first
three fractions in the lower temperatures suggest a possible excess component, but it could be 39Ar recoil effectduring irradiation. It was difficult to control the temperature above 700-800oC due to the abrupt change of emissivity, and the temperature was brought up to fusion in
the last fraction. The change of emissivitiy is caused by
the structural phase transition. However, the plateau-likeage reasonably agree with the age of biotite in the previous results, giving a consistent age of the tuffs. On the

39

Ar/ Ar

EXPERIMENTS: Experimental procedure is the sameas described as previous studies. Rock samples werecrushed, and sieved in #25-50 mesh. After ultrasoniccleaning in distilled water, single mineral grains werehandpicked. The minerals were irradiated in the KUR for
24 hours at 1 MW for 40Ar/39Ar age determination. The
total neutron flux was monitored by 3gr hornblende age
standard [2], [3], which was irradiated in the same sample
holder. In the same batch, CaSi2 and KAlSi3O8 salts wereused for interfering isotope correction. A typical J-value
was (5.499 + 0.022) X10-3. In stepwise heating experiment, temperature of a mineral grain was measured using
infrared thermometer whose spatial resolution is 0.3 mm
in diameter with a precision of 5 degrees. Extracted argon
isotopes were measured using the custom made mass
spectrometer [4].

37

INTRODUCTION: Direct radiometric dating of fossil
bearing strata is technically difficult if they do not contain a mineral coeval with the sedimentation. Recent
study indicates correlation of some mammals and humanbeings [1]. The study area has fossils of mammals, which
seem to be associated with hominidae. In the previous
studies, 40Ar/39Ar dating on the tuffs overlying immediately on the fossil bearing layer, was applied on mainly
biotite, and they yielded ages of approximately 20Ma.
However, some of the samples show quite disturbed age
spectra, suggesting effects due to later alteration and/or
weathering. Whole rock samples dated by K-Ar and mostresults distribute around 17 – 18 Ma. We separated thefeldspars which seem to have less alteration under microscope.

Apparent Age (Ma)UG09081403-3F1
40
21.1 + 1.0 Ma
30
20
10

0
100
50
0
0.0

0.2

0.4

0.6

0.8

1.0

Fraction of 39Ar released
Fig. 1. 40Ar/39Ar age and 37Ar/39Ar ratio spectra ofa feldspar from volcanic ash strata in Uganda. The
37
Ar/39Ar ratio spectra suggest very low Ca and ahomogeneous mineral phase at high temperature.
The age and other plateau-like age spectra in biotite
imply the age of volcanic activity is about 20 - 21Ma.

other hand, 40Ar/39Ar age of whole rock samples are variable. Because of their various ages, whole rock samples
may carry significant alteration.
REFERENCES:[1] Y. Kunimatsu and 13 others (H. Hyodo at the 6th).
Proceedings of National Academy of Science 104(2007) 19220-19225.
[2] G. Turner, J.C. Huneke, F.A. Podosek and G.L. Wasserburg, Earth Planet. Sci. Lett. 12 (1971) 19-35.
[3] J.C. Roddick, Geochim. Cosmochim. Acta 47 (1983)
887-898.
[4] H. Hyodo, Gondwana Research 14 (2008) 609-616.

採択課題番号 24066
東アフリカ地域火山灰の 40Ar/39Ar 年代 II（岡山理科大・自然研）兵藤博信、板谷徹丸

一般通常CO5-13

Geochemistry of Unbrecciated Diogenite, Yamato 002875

N. Shirai, S. Sekimoto1 and M. Ebihara
Department of Chemistry, Tokyo Metropolitan University
1
Research Reactor Institute, Kyoto University
INTRODUCTION: Howardite, eucrite and diogenite(HED meteorites) are the largest group of achondrite
which are thought to have been derived from asteroid
Vesta. Recently, the Dawn mission confirmed that the
Vesta’s surface is mineralogically and chemically similar
to HED meteorites [1]. Depletions of siderophile elements in HED meteorites suggest that HED meteorites areproducts of differentiation [2]. Therefore, HED meteorites are important to elucidate the core formation of Vesta.
Diogenite are mostly composed of orthopyroxene withsuch minor minerals as olivine, plagioclase and chromite.
As almost all diogenites are brecciated, it is difficult tobring out their primitive chemical compositions. Some
diogenites (e.g., Ellemeet and MIL 07001) were reported
to contain foreign meteoritic components [e.g., 3]. Fromthese materials, siderophile elements abundances may
have been modified. A few unbrecciated diogenites havebeen found. As siderophile elements abundances for these unbrecciated diogenites were not affected by the incorporation of foreign materials, its chemical compositions give us the important information about the differentiation processes of Vesta. Yamato (Y) 002875 discovered by Japanese Antarctic Expedition Team was classified as an unbrecciated diogenite. This meteorite is nearlymonomineralic diogenite composed of >99 % orthopyroxene. In this study, we determined elemental abundances for Y 002875 by using INAA and aimed to chemically characterize this meteorite in comparison withthose for other diogenites.
EXPERIMENTS: Several chips of Y 002875 weighing
3.119 g were carefully ground in an agate mortars in order to obtain the representative chemical composition. In
addition to this meteorite, we also analyzed Y 74013 andY 74097, for which a total of 3.152 g and 3.100 g ofchips were ground to powder in clean agate mortars.
Powder samples of three diogenites were irradiated twotimes with different irradiation periods at KURRI. Both
JB-1 and the Smithsonian Allende powder samples wereused as reference standards.
RESULTS AND DISCUSSIONS: Our data for Y 74013
and Y 74097 are generally in good agreement with literature values [e.g., 4]. Our Cr and V values for Y 74013
and Y 74097 are consistent with the ranges for these elements of other diogenites, while literature values forthese meteorites are higher. The differences of Cr and V
abundances between our data and literature values are
due to the heterogeneous distribution of chromite.
Based on mineralogy, petrology and bulk chemical compositions, Yamato diogenites are divided into two cate-gories: Type A (Y 74013-type) and Type B (Y74032-type). For pyroxene and chromite, mg number for
Type A diogenites are higher than those for Type B diogenites. Plagioclase is present in Type A diogenites, but
not in Type B diogenites. In bulk chemical compositions,Type B diogenites have higher incompatible elementsabundances compared with Type A diogenites. An mg
number and incompatible elements of Y 002875 are consistent with those for Y 74013 and Y 74097 and fall in
the range of Type A diogenites. Thus, Y 002875 is
chemically similar to Yamato Type A diogenites.
Figure 1 shows CI-normalized Ni/Co ratio and Ni abundances in diogenites. As shown in Fig. 1, there is no difference of Ni abundances and (Ni/Co)CI ratios between
brecciated and unbrecciated diogenites. Being similar tothe case for eucrites, Ni abundances and (Ni/Co)CI ratios
systematically correlate among diogenites. We calculated
Ni abundances and (Ni/Co)CI ratios of the mixture of thepristine diogenitic material and chondrite or FeNi-metal
by changing mixing ratios of these two components.
Calculations results are shown in Fig. 1. Apparently,
contamination of chondritic material or FeNi-metal could
explain systematically correlation between Ni abundances and (Ni/Co)CI ratios in diogenites. Even unbrecciateddiogenites were affected by the contamination of foreignmaterials, suggesting that its incorporations were occurred before unbrecciated diogenites were crystallized.

Fig 1. Ni abundances vs. (Ni/Co)CI ratios for diogenites. Solid and dashlines represent mixing line of the pristine diogenitic materials and FeNimetal or chondritic clast, respectively. The numbers along these lines
correspond to contributions in % of the FeNi-metal and chondritic clast.

REFERENCES:[1] M. C. De Sanctis et al., Science 336 (2012) 697-700.
[2] K. Righter and M. J. Drake, Meteorit. Planet. Sci., 32(1997) 929-944.
[3] D. W. Mittlefehldt, GCA, 58 (1994) 901-912.
[4] D. W. Mittlefehldt and M. M. Lindstrom, Antarct.
Meteorites, 6 (1993) 268-292.

採択課題番号 24072	
 放射化分析法による宇宙・地球化学的試料の元素組成の定量	
 
共同通常	
 
（首都大学東京・理工）白井	  直樹，大浦	  泰嗣，海老原	  充（京大・原子炉）関本	
  俊	
 CO5-14Comparison of RNAA Data with ICP-MS Data for Halogen
in Sedimentary Rock Samples

M. Ebihara and S. Sekimoto1a

A ratio for JCh-1 is ruled out (see text for details).

JSd-3

JCh-1

JSd-2

JSd-1

JSL-2

JSL-1

JLs-1

JDo-1

JSd-3

JSd-2

JSd-1

JSL-2

JSL-1

JLk-1

0.5

0.5
JLs-1

0.92±0.19a

1.00±0.08
0.84±0.10
0.94±0.1

JDo-1

1.07±0.13
2.22±1.54

JLk-1

JSd-3
JCh-1
Mean

Ratio of ICP-MS to RNAA

Ratio of ICP-MS to RNAA

consecutive measurements of one solution sample. Although the two sets of data are fairly consistent between
Graduate School of Science, Tokyo Metropolitan UniverRNAA and ICP-MS, it can also be seen that the ICP-MS
sity
data are systematically lower than the RNAA data. In
1
Research Reactor Institute, Kyoto University
particular, ICP-MS data for bromine for three samples(JLs-1, JDo-1, and JSd-1) are lower than the correspondINTRODUCTION: Accurate and reliable data of haling RNAA data, even with the uncertainties being conogen abundance have been rarely reported for terrestrial
cerned. A similar situation can be seen for iodine in four
samples, such as crustal rock and mantle material, thoughsamples (JLs-1, JDo-1, JSL-1, and JCh-1). However, thehalogens differ in volatility from element to element and
ICP-MS data for bromine and iodine are very consistenttheir content and relative abundance are highly informawith the RNAA data for two samples (JLk-1 and JSd-3),
tive in discussing the petrogenesis of samples [1].
where bromine and iodine contents are relatively highThe shortage of accurate and reliable data of terrestrial
compared with those in the other seven samples. In therock samples is largely related to difficulties in detersample containing more than a few mgkg-1 bromine
mining trace amounts of halogens within these samples.
and/or with more than 1000 gkg-1 iodine, consistent data
To determine trace halogens in rock samples, either inbetween RNAA and ICP-MS are likely to be obtained.
ductively coupled plasma mass spectrometry (ICP-MS)
Although inconsistency between RNAA data andor neutron activation analysis (NAA) have commonly
ICP-MS data cannot necessarily be seen for a sample
been utilized. Bromine and iodine are conventionallysuch as JSL-2 where bromine and iodine contents are
determined by ICP-MS after preconcentration of the elerelatively low, ICP-MS data of both bromine and iodine
ments using pyrohydrolysis of rock powder [2].
are evidently lower than RNAA data for the limestone
In this work, trace three halogens (Cl, Br and I) were
sample (JLs-1), which consists mainly of calcium cardetermined by radiochemical NAA (RNAA) for nine
bonate and is decomposed into refractory calcium oxide
sedimentary rocks. Our RNAA values are compared with(having a high melting point of 2927 K) and carbon dithe ICP-MS values for the nine sedimentary rock samples
oxide on heating.
in order to evaluate the consistency of the two data sets.
Presumably, the quantitative collection of bromine andSince there was no chlorine data available from ICP-MS,
iodine cannot always have been achieved in the pyrohyonly bromine and iodine data could be compared.
drolysis procedure [2]. This suggests the limitation of the
EXPERIMENTS: Trace amounts of Cl, Br and I in thepyrohydrolysis procedure in the determination of halonine sedimentary rocks were determined by RNAA. The
gens (at least bromine and iodine) by ICP-MS. It may be
RNAA procedure is described elsewhere [3].
noted, however, that RNAA and ICP-MS data agree
RESULTS: Our RNAA values are compared with thewithin 10% for both bromine and iodine, as shown by the
ICP-MS values [2] for all nine sedimentary rocks in Table
mean values of individual ratios, and further that ICP-MS
1, where concentration ratios of ICP-MS values to RNAA
coupled with pyrohydrolysis can work well for suchvalues are given. These ratios are plotted in Fig. 1, where
studies where only rough abundances of halogens areratios for concentrations of bromine (Fig. 1a) and iodine
required. However, if accurate values of halogens are(Fig. 1b) are compared separately. In calculating theessential for the study, which corresponds to the analysis
mean ratio of bromine, a value for JCh-1 was ruled outof reference samples, RNAA is the best choice of analytusing the outlier test under the 2-criterion. An uncerical procedure. There is also an advantage of choosing
tainty quoted for each ratio is simply the value calculated
RNAA over ICP-MS when the sample mass used forfrom two individual uncertainty values accompanied byanalysis is limited and duplicate analyses are not possible
RNAA and ICP-MS data. Please note here that the unor desirable, as is the case when analyzing extraterrestrial
certainty of RNAA is a standard deviation (1) of threesamples such as meteorites and lunar samples.
or four separately determined values, whereas the uncerREFERENCES:
Table 1. Ratios of ICP-M S values to RNAA values tainty of ICP-MS is a[1] N. Imai et al., Geostandards Newsletter, 20, 165-216
standard deviation of
ICP-MS/RNAA
Sample(1996).
several (normally three)
BromineIodine[2] J.Y. Chai and Y. Muramatsu, Geostandards and GeoJLk-1
1.02±0.08
1.03±0.07
analytical Research,
Ratio=1
Ratio=1
1.5
1.5 Bromine (a)
Mean
Mean
JLs-1
0.65±0.1
0.82±0.1
Iodine (b)31, 143-150 (2007).
JDo-1
0.85±0.08
0.90±0.09[3]
S. Sekimoto andJSL-1
0.89±0.14
0.80±0.08
1
1M.
Ebihara,AnalytiJSL-2
0.90±0.16
1.04±0.13
1 region1 regioncal
Chemistry,in
JSd-1
0.89±0.06
0.95±0.09
JSd-2
1.04±0.07
1.09±0.11
press.

Fig.1 Concentration ratio of bromine (a) and iodine (b)between RNAA values and ICP-MS values.

採択課題番号 24086 宇宙・地球化学試料中の微量ハロゲン(Cl, Br, I)の中性子放射化分析 共同通常
（首都大学東京・大学院・理工）海老原 充（京大・原子炉）関本 俊

CO5-15

Cadmium Analysis in Pigments by INAA

E. Furuta, Y. Nakano1, R.Okumura1 and Y. Iinuma1
Ochanomizu University
1
Research Reactor Institute, Kyoto University

INTRODUCTION:
Pigments include many kinds ofheavy metal elements. It is famous that arsenic (As)was included in the hair of Napoleon Bonapartebecause the paint on the wall tiles included it. It
became clear by the analysis of INA [1]. When pigment
includes toxic heavy metal elements, it becomes risk forhuman.
Many pigments named cadmium (Cd) are sold of
not only the color of yellow but also red, orange andgreen. On the other hand, there are many same color
pigments without claiming cadmium. Pigments wereanalyzed by INAA to study the concentration of Cd inthem. At the same time, the pigments were checked on
the indications for relationship to health risk.
EXPERIMENTS: Samples were oil paints, acrylic
paints, water paints and powder. Numbers of samples
were 23, 5, 6 and 6, respectively. Each sample weight
was measured and if it was necessary, some of them weredried under the infra-red lamp. Each of them was
enclosed in a double polyethylene bag. The standard
samples used were JA-2 and JR-2 of rock standard, and10 ppm Cd and 50 ppm mercury of atomic absorption
reagents were used applying to a filter paper. The
samples were put in capsules with the standards andirradiated 5MW × 10 min or 1MW × 30 min at KUR.
After cooling among 5 days, the capsules were opened,
and then measured the gamma-rays of medium and long
half life radionuclides.

were detected in them from a few ppm to a few hundred
ppm. All sorts of pigments included Cd when they werenamed cadmium; it does not depend on the pigment sorts
except for color pencils.
Discussion:
There was no information of theconcentration of Cd included in the pigments. So, morethan 40 samples were put in one capsule and irradiated.
The concentration of Cd was high from a few percentage
to a few ten percentage in many samples named
cadmium, so it was considered that the neutrons wereabsorbed at many points and the results were not correct.
So such the high Cd concentration samples were notsuitable for INAA. On the other hand, the sample
preparation was only dryness for INAA; undestroyed
method. Except for Cd high concentration case, the
INAA method is easy to analyze pigments which wereorganic and inorganic compounds mixture. In a near
future, the samples are planned to analyze by afluorescent X-ray method.
The indications on the pigments for health risk wereas follows; 1. Not the all pigments including Cd hadmarks for health risk. 2. When the indications were on
the pigments, there were a few marks. 3. These marks
were shown little explanation. As these situations, users
can not decide that the pigments are safe or not. It isconsidered that same marks will be necessary for all over
the world and explanations of the marks will benecessary for safe use of pigments.
REFERENCES:[1] P. Lewin et al. Nature, 299 (1982) 627-628.

RESULTS: The pigments named cadmium included
Cd from approx. 4 ppm to 46%. Also the pigments
named cadmium-red or -orange included not only Cd but
also mercury; a few ten ppm. Other elements such as
sodium, calcium, iron, cobalt, barium and chromium

採択課題番号 24094
画材に含まれる有害金属元素の定量（お茶の水女子大学）古田悦子 （京大・原子炉）中野幸廣、奥村良、飯沼勇人

共同通常

CO5-16

Neutron Activation Analysis of Trace Mn in Iron Meteorites

Y. Tanaka, A. Tanaka, Y. Oura1, K. Akiyama1
S. Sekimoto2 and R. Okumura2
School of Science and Engnieering, Faculty of Urban
Liberal Arts,Tokyo Metropolitan University
1
Graduate School of Science and Engineering, Tokyo
Metropolitan University
2

Research Reactor Institute, Kyoto University

INTRODUCTION: Meteorites contain cosmogenic
nuclides produced by a nuclear reaction with cosmic rays.
Cosmogenic nuclides are useful for determination of exposure and terrestrial ages. In general, only radionuclides
and noble gas stable-isotopes can be detected as cosmogenic nuclides. Although it is difficult to detect cosmogenic stable nuclides in stony meteorites, some cosmogenic stable nuclides could be detected in iron meteorites,
which consist of mainly an iron–nickel alloy, since ironmeteorites have little geochemical lithophile elements.
Among such stable nuclides we focus on Mn.
But
Natural Mn is a monoisotopic (55Mn) element.
iron meteorites have also a cosmogenic radioisotope,
53
Mn, which has longest half life among detectable cosmogenic radionuclides. One of practical methods fordetermination of 53Mn is a preconcentration neutron activation analysis (preNAA) using 53Mn(n, γ)54Mn reaction. We suggested that 55Mn content should be requiredfor determination of ultra trace 53Mn in iron meteorites
by preNAA because of correction of 55Mn(n, 2n)54Mn.
But accurate concentration in iron meteorites is rarely
reported. Almost 53Mn in iron meteorites is extrapolated
to be comsogenic by 45Sc contents [1]. If accurate 55Mn
concentration can be determined, 55Mn-53Mn system for
exposure age will be also established. And estimation oforiginal 55Mn concentration is interesting for consideringa differentiation of planets. Determination of 55Mn iniron meteorites by NAA is well known to be interferedby 56Fe(n, p)56Mn reaction. Therefore, the removal ofiron prior to irradiation or irradiation at a channel withhigh Cd ratio is required. Thus we tried to determine55
Mn concentration in iron meteorites by preNAA using
well thermalized neutrons.
EXPERIMENTS: Using radiotracers, a chemical procedure using an ion-exchange method was developed forseparation of Mn from iron meteorites based on one by
Fujimoto and Shimura [2]. After dissolution of a sample
in 2 M HF, the HF solution was loaded on a cation exchange resin. Adsorbed Mn was eluted by 8M HCl, andthen Mn in HCl - 2-propanol solution was purified by ananion exchange method. This procedure was applied toJapan steel standard samples and Gibeon iron meteorites

followed by irradiation of separated Mn fraction for 4
hours at the thermal column pneumatic transport system(Tc-Pn) and for 1 hour at Pn-2 in Kyoto University Research Reactor (KUR). In addition, sensitivity of 55Mn(n,g)56Mn and contribution of 56Fe(n, p)56Mn at Tc-Pn in
KUR and at PN-3 in the Japan Research Reactor-3(JRR-3), Japan Atomic Energy Agency were evaluatedby using Mn standard and Ti plate, respectively.
RESULTS: In Mn fraction irradiated for 1 h at Pn-2, no
59
Fe and 60Co was observed. Our chemical procedure
removed > 99.99% of Fe and Co and > 99.5% of Ni, Ir
and Cr, and overall procedure blank of Mn was about 30
ng. Determined Mn concentration in steel standards(JSS003-5 and JSS001-5) and Gibeon meteorites areshown in Table 1. Low determination values in Run-1
were guessed to be caused by low chemical yield. In
Run-2 a chemical yield was estimated to be 91% anddetermined concentrations on Mn in steel standards wereconsistent with certified values. It is concluded that down
to 30 ppb of Mn can be determined by our method.
Sensitivities of Mn were 930 cps/mg and 2400 cps/mg
for 4 h irradiation at Tc-Pn and 20 min irradiation at Pn-3,
respectively. And contributions of (n, p) reaction werecorresponding 16 ngMn/gFe and 97 ngMn/gFe for Tc-Pn
and PN-3, respectively. Since Fe was sufficiently removed, contribution of 56Fe(n, p) reaction was more than
150 times smaller than the present procedure blank. A
detection limit of Mn by preNAA was 30 ppb, assumingthat a half of induced 56Mn is resulted by a blank. Even
INAA using Tc-Pn can determine such concentration of
Mn. Reducing a procedure blank is highly required forlower detection limit.
Table 1: Result of Mn content
S am ple

U nit

IN A A *JS S 003-5
JS S 001-5
G ibeon

ppm
ppb
ppb

24.9 ± 0.2
36.1 ± 2.2

preN A A
run1
run2
19.8 ± 0.4 26.0 ± 0.3
27.5 ± 2.2
273 ± 9415 ± 7

C ertified
V alue27 ± 130 ± 10*Corrected for (n, p) reaction.

REFERENCES:[1] Oura et al., Proc. Radiochim. Acta 1, 383 (2011).
[2] K. Fujimoto and M. Shimura, Bunseki Kagaku 50,
175 (2001).

This content was submitted to APSORC-13 international
conference.

鉄隕石中の微量マンガンの中性子放射化分析	 採択課題番号 24099	
 （首都大・理工）大浦泰嗣，秋山和彦，田中義久，田中景	
 （京大・原子炉〕関本俊，奥村良	
 

共同通常	
 

CO5-17 Study on Sorption Behavior of Trace Elements in Sedimentary Rocks and Bentonite
Using Sequential Extraction Method
T. Honda, K. Torigata, S. Sekimoto1 and R. Okumura1
Graduate School of Engineering, Tokyo City University
Research Reactor Institute, Kyoto University

Sequential extraction was used to analyze the behaviorof the elements in the samples. The extracted solution
and the residue were analyzed by NAA and ICP-MS.

1

INTRODUCTION:
One of the major problems with nuclear power is thedisposal of high-level radioactive waste (HLW). The accident at the Fukushima Daiichi Nuclear Power Plant has
highlighted this issue.
Initially, HLW is highly radioactive, and takes about
hundred thousand years to reach the same level of radioactivity as natural uranium ore. Geological disposal isused to isolate HLW for long time periods. Geologicalrepositories contain a multi-barrier system of artificial
barriers made of over-pack and cushioning bentonite clay,
and natural barriers consisting of geological formations.
Minor actinoid (MA) radionuclides, such as 237Np, 243Am
and 247Cm, which are produced by the neutron capture
reaction of uranium, are present in HLW.
Although it is crucial to evaluate the behavior of MAs in
the multi-barrier system over tens of thousands of years,
MAs are very difficult to observe experimentally because
they are extremely toxic and produced artificially in only
limited quantities.
In this study, we have used the lanthanoids (Lns), Th
and U as natural analogues for the MAs in order to determine the sorption behavior of the elements in flowing
artificial groundwater with a sequential extraction method[1-2].
SAMPLES AND EXPERIMENTS:
The samples were collected from boreholes drilled by
the Horonobe Underground Research Center of the Japan
Atomic Energy Agency. The bentonite was purchasedfrom Kunimine Industries Co., Ltd.
The trace elements (Lns, U and Th) were determined byneutron activation analysis (NAA) of the pulverized
samples at the Kyoto University Research Reactor (KUR;
Table 1). The artificial groundwater was produced byadding the Lns to natural groundwater.
The groundwater conditions were as follows: pH 8.0,
temperature 18 °C, flow volume 5 L, flow rate 3 mL/min,
Ln concentration 10 ppb.

Kyoto
Univ.
KUR

RESULTS:
Figure 1 shows the sequential extraction results. In step
2 (■) the Dy concentration increased compared with theblank. This suggests that Dy may co-precipitate with Mg.
The results can be summarized as follows:(1) natural analogue elements such as Dy may precipitate
as hydroxides and co-precipitate with magnesium andferric hydroxide;(2) the light Lns (La-Eu, Kd: 0.97 (max)) adsorb to magnesium and ferric hydroxide more easily than the heavy
Lns (Gd-Yb, Kd: 0.81 (minimum));(3) heavy Lns adsorb to pyrite and organic matter moreeasily than the light Lns[3];(4) the natural analogue elements in bentonite, such as
Dy, form sulfides following silicates; andFig. 1 Sequential extraction results for the major elements(left) and for Dy (right).

(5) bentonite and sedimentary rocks may delay the migration of MAs in groundwater to the surface, because
the MAs may precipitate with Mg and Fe.
REFERENCES:[1]K. Torigata, T. Honda, T. Iwatsuki, H. Murakami,
Fission Track News Letter, No.25, 28-31(2012)[2]K. Suzuki, T. Honda, Fission Track News Letter,
No.24, 60-62(2011)[3] A. Ohta, Geochemistry, 40, 13-30 (2006)

Table 1. Irradiation conditions of KUR
Max thermal
Half
Irrediation
Irradiation
Output(MW) neutron flux
times
locationtimes(n/cm2/s)
13
Long
PN-2
5
1hour
2.75×10
Short

PN-3

1

4.68×1012

40sec.

採択課題番号 24104 逐次溶解法を用いた堆積岩並びにベントナイトにおける微量元素
収着挙動に関する研究(都市大院・工)本多照幸、鳥潟一文(京大・原子炉)関本 俊、奥村 良

共同即時

CO5-18

Geochemical Mapping for the Upper Ara-river System Area, Saitama Prefecture
by Neutron Activation Analysis (II)T. Fukuoka, Y. Saito1, M. Ishimoto2, H. Kusuno,
H. Inagaki, Y. Okubo and N. Fujinaga
Faculty of Geo-environmental Science, Rissho University
College of Science and Engineering, Aoyama Gakuin
University
2
School of Engineering, The University of Tokyo

1

INTRODUCTION: Geochemical maps express areal
distributions of chemical elements in the earth’s land
surface and give information about the chemical background in the natural environment to assess the artificial
environmental changes [1, 2]. In this study, we report thegeochemical mapping for the upper Ara-river system,
Chichibu Mountain area, Saitama in 2012. Cosmo-Geochemistry Lab., Rissho University has been
making up the geochemical maps since 2000.
EXPERIMENTS: We analyzed the stream sediments
which had been collected as a sample representing thegeochemical characters in each drainage basin. A sampling site 1 per 1 km2 was selected in the area which a
mountain ridge was surrounding and at 100m upperstream in the branch from the junction of main stream to
avoid the contamination by floods. The stream sediment
was sieved to 80 mesh (<180 µm) on site and the fine
fraction was reserved for analysis. 47 elements in collected samples are analyzed by X-ray Fluorescence
Analysis (XRF), Laser Ablation Inductively Coupled
Plasma Mass Spectrometry (LA-ICP-MS), Prompt
Gamma-ray Analysis (PGA) and Instrumental Neutron
Activation Analysis (INAA). INAA has great advantage
for Au, As and Sb analyses compared with ICP-MS, because of their low ionization potential.
RESULTS: Japanese character Kanji“金” means gold (Au). Places around placename 金沢(Kanazawa), 金山(Kanayama),
and 金崎(kanesaki) are possible
Au-producing district. In 2012 year study
area, there were 4 possible Au-producing
districts (1223, 1224, 1225 and 1235)(Fig.1).
The geochemical maps of As and Sb indicate similar distribution of these elements
and similar to Au. Table 1 shows the ana-

lytical results of Au, As and Sb for the above four districts samples by INAA. The results indicate only one
district (1235) has high Au and As contents comparedwith those for another possible district samples, although
the Sb contents is not so high. Sampling point of thesample 1235 is down stream from “Kanezaki.” This suggest that place-name 金崎(Kanesaki) is Au producing
district.
In 2011 study, the Au content in a sample was extremely
high (22,560ppb), although As and Sb contents werenormal [3]. In this study, the Au, As and Sb contents inthe sample were analyzed again by INAA. The results for
those elements of the sample in this study are just normal.
High Au, As and Sb contents were not obtained. Thissuggest that the high Au content in 2011 study was artificial contamination for the sample. This sampling point is
not Au producing district.
REFERENCES:[1] Darnley, A. G. et al. (1995) 19, UNESCO Publishing,Paris. K.
[2] Johnson, C. C., Brown, S. E. and Lister, T. R. (2003)
Internal Report, IR/03/096N. British Geological Survey, Keyworth, Nottingham.
[3] Fukuoka, T. et al. (2012) KURRI Progress Report
2011, 256.
Table 1. Au, As and Sb contents in samples 1223, 1224, 1225 and 1235
Sample Au
As
Sb Sampling point
nameppb ppm ppm
Down stream from “Kanazawa” and “Ka1223
ND 7.4 0.1 nayama”
As above

1224

1.4

12.6

0.1

1225

ND

3.0

ND As above

1235
26.7 10.9*ND: not detected

0.1

Down stream from “Kanesaki”

Kanazawa
Kanayama

KanesakiFig. 1. Tophgraphic map showing sampling points● Sampling point

0

1

2 km

採択課題番号 24105
中性子放射化分析による地球化学図の作成
一般即時（立正大・地球）福岡孝昭、楠野葉瑠香、（青山学院大・理工）齋藤裕子、（東大院・工）石本光憲