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The 28th symposium on age measurements with AMS (accelerator mass spectrometry) and EPMA (electron probe micro analyzer) systems, as well as their applications to geological and archeological samples, was opened on January 28th-29th, 2016, at Nagoya University. Symposium of this kind has been held every year generally as an opportunity for users' meeting to publicize their results obtained by utilizing the age-measurement facilities of the Division of Chronological Research, Institute for Space-Earth Environmental Research, Nagoya University. The institute was re-organized by merging three research divisions: (1) Solar Terrestrial Environmental Research; (2) Institute for Hydrospheric and Atmospheric Research; (3) Center for Chronological Research. This symposium has been organized by the previous Center for Chronological Research for 27 years. In this symposium, the status reports of the AMS and EPMA systems were delivered. In addition, a special lecture, and two state-of-art invited lectures as for the topics using the AMS as well as EPMA systems of our division were presented. A poster report was also presented as the results of the program of the innovation of new technology and research for young scientists. A special lecture, given by Prof. Toshio Nakamura, was entitled as "Recent development of techniques of accelerator mass spectrometry and its expanding applications". He summarized briefly the history of research on AMS in Japan lasting from 1979 to present and discussed future prospective of AMS techniques. Next, two invited lectures were presented at the symposium: the first talk was entitled "Possible early Archaean biosphere interpreted from ca. 3.8 Ga Isua rocks, West Greenland", presented by Dr. Yoko Ohtomo from Graduate School of Engineering, Hokkaido University. She visited the Isua province, Greenland, to look for graphite layer in the sedimentary rocks. The graphite should be a relic left by living things of 3.8 billion years ago. She successfully found the graphite and brought it to Japan, and investigated its origin by an optical microscope, an electric microscope and carbon isotope ratio analysis. The results will be summerized as a report in this proceeding book. The second talk entitled "Seasonal characteristics of aerosol PM2.5 collected in Noto Peninsula" was given by Professor Atsushi Matsuki, the Institute of Nature and Environmental Technology, Kanazawa University. He studies aerosol, a hazardous atmospheric particles to human bodies, collected at a local city, Wajima, far from big urban cities, in focusing on such elemental processes as: (1) continuous measurements of concentrations, and some other aspects of the PM2.5 particles; (2) evaluation of specific cloud formation character of aerosols; (3) investigation of origins of carbonaceous fractions of PM2.5. The detail results will be described in the manuscript in this proceedings book. Totally 21 oral reports and 7 poster reports were presented as contribution papers concerning the results on applications of the AMS as well as EPMA systems of the CCR. The fields of such applications are: study on solar activity based on 14C concentrations of tree rings; preparation water samples for 14C content measurements; 14C dating analysis of charcoal and bone samples from archeological and cultural property samples; 14C dating study of archeological bronze artifacts; geological applications of 14C dating, including cored samples from Hokkaido; 14C dating application to cultural properties such as old Japanese swords and mortal materials; studies on 14C calibration with Japanese wood; technical developments of sample preparation for 14C measurements; CHIME dating of monazite; technical study on CHIME dating for sub-micron sized samples. Finally, it should be noted that general participants who are not a specialist of age measurements or applications also joined the discussion and hopefully enjoyed it., 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

A model 4130-AMS 14C analyzer, produced by General Ionex Corporation, USA, was successfully introduced to the Radioisotope Center, Nagoya University, in 1981/82. The first 14C signal was detected with the machine in February 1983 and routine 14C measurements were started in the autumn of 1983. The AMS system has processed totally 8,652 unknown samples by July in 2000, after that time, he transferred his role of 14C measurements to another new successor. A second AMS system, dedicated to high-precision and high-accuracy 14C measurement, with a recombinator system to measure three carbon isotopes 12C, 13C and 14C simultaneously, produced by High Voltage Engineering Europe BV, The Netherlands, was installed in 1996/97. 14C measurements with the machine were started in 1999 and the machine has measured totally 23,921 graphite targets by the end of December 2015. Following the results of applications of the two AMS system for 14C measurements at Nagoya University, a brief history of the developments of AMS techniques and applications mainly in Japan is described. In addition，future perspectives of AMS are discussed., 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

We have initiated the Radiocarbon Intercomparison on Chemical Experiments, Water series (RICE-W) program in 2013 to examine whether carbon isotopic fractionation and carbon contamination occur or not in sample preparations for water 14C analysis. At first, we examined the air-shielding effect of some bottles for water storage and the effectiveness of addition of toxic substance (e.g. HgCl2 solution), using eight water samples (seawater, hot-spring water, groundwater, and NaHC03 solution). Secular 14C change for ～500 days showed that (1) the polyacrylonitrile or glass bottle is appropriate for sample storage, (2) polypropylene bottle is not appropriate on water 14C analysis, and (3) the employment of a toxic substance to suppress biological activity is necessary. However, sterilized samples are not suitable in this program, because they require special procedures for transport, disposal and experiment. Thus, we prepared new water standards, RICE-W09-W14, using solution of chemical reagents and dissolved CO2 without a toxic substance. The chemical compositions of the standards were arranged to be similar with natural waters having a wide range of 14C concentration. The second stage of the RICE-W program is starting now, and we welcome laboratories participating this program., 水試料の放射性炭素濃度測定の分析機関相互の比較検証(RICE-W)において，本格始動に向けての基礎的な検証を行った．比較検証の際に重要なことは，14C濃度が同じ水試料を各機関へ配付すること，配付から分析処理までの期間に14C濃度が変化しないことである．そのためには，どのような容器に入れて保管すればよいのか，水試料はどういったものが良いのか，について検討が必 要である．ガラス，PAN樹脂，pp樹脂の3種類の容器を検討した結果，ガスバリア性能に違いがあることがわかった．容器の取扱の利便性と合わせて考慮した結果，本プロジェクトではPAN樹脂容器を採用することとした．また，天然試料の場合，生物活動による影響が無視できないことがあり，毒物の添加が必要であるとの結論を得た．そこで，天然試料をベースとした相互比較試料の作成をあきらめ，完全に人工的にコントロールした相互比較試料を作成することとした．いくつかの試薬を混合して，現代からバックグラウンドレベルまでをカバーするような14C濃度の範囲であり，天然試料を模した化学組成の相互比較試料（RICE-W09-W14）を新たに作成した．本プロジェクトは，多機関による相互比較の実施に向けて，次のステップに進む段階にある．多くの機関からの参加を期待している．, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

The authors have been studied deposits of Late Pleistocene to Holocene in the basin of the Azuma River since spring in 2013 by the use drilling cores. In the year of 2015 they obtained two cores (HAP-1 and AKP-1) by hand-operated sampler, and investigated the cores in the method of lithologic observation, pollen analysis, diatom analysis, tephrochronology and AMS 14C-dating. In addition to the study they performed the lithologic observation and pollen analysis of two cores (AZK-103 and AZK-112) obtained by drilling machine., 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

The lower part of the AZK-103 core consisted of Picea forest , and the part above it consisted of 86% Sphagnum. Above this, the proportion of Quercus forest decreased gradually. At the lowermost part of the AZK-112 core, coniferous forest material consisting mostly of Picea was observed. In the part from after the time when Sphagnum was dominant, the amount of forest from Quercus, which accounted for 23% at the beginning of the Holocene, gradually decreased. After marine regression, Typha or Sparganium, which may have originated in nearby ponds, appeared in the Hamaatsuma (HAP-1) core. Ferns subsequently became predominant, and Quercus and Alnus forests then gradually expanded. In the Atsunantyugaku (AKP-1) core, ferns also became predominant after marine regression and were later replaced by Nuphar, which originated in nearby ponds. The subsequent rapid expansion of Quercus forest was followed by continuous expansion of Alnus forest . As in HAP-1 core, Alnus and Quercus forests coexisted with ferns during this period., 厚真川下流域のAZK-103コアの最下部はトウヒ属林でミズゴケ86%産出部を経て，25%のコナラ亜属林は漸減した．AZK-112コアでも最下部はトウヒ属林でミズゴケ属の多い時代を経て，完新世の23%コナラ亜属林は漸減していった．浜厚真（HAP-1）コアは池塘由来かもしれないガマ・ ミクリの時代を経てコナラ亜属林とハンノキ属林が拡大した．厚南中学（AKP-1)コアも池塘由来のコウホネの産出後コナラ亜属林が拡大その後ハンノキ林が急拡大し羊歯植物に覆われた．, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

Four types of diatom assemblage （fresh water, brackish water, marine water and compound assemblage of fresh and marine water species) were detected in alluvial deposits of the Azuma incised-valley area. Environmental changes from late Pleistocene to Holocene were discussed by distribution of diatom assemblages and AMS 14C datings. The first evidence of marine water by the Jomon transgression was recognized in TP-44.24 m altitude of the AZK-101 core (11.8 Cal ka). During a transgression, marine offshore water was predominant. The horizon of the environmental change from brackish to fresh waters was recognized in TP-0.2 m altitude of the S60K-1 core (5.7 Cal ka)., 厚真川流域の沖積層から4つの群集タイプ(淡水域の群集,汽水域の群集,海水域の群集,淡水域の群集(淡水生種と海水生種の混合群集))を識別し，その時空分布とAMS14C年代から後期更新世から完新世の古環境変遷について議論した．最初に海の浸入の証拠が認められるのは，AZK-101コアの標高-44.24mである(11.8Cal ka)．その後，縄文海進の進行に伴い，当地域は広く外洋水の影響を受ける水域となった．淡水化するのはS60K-1コアの標高-0.2mである(5.7Cal ka)．, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

An AMS system (Model 4130-AMS) dedicated to 14C measurements, built by High Voltage Engineering Europe (HVEE), B.V., The Netherlands, was delivered to Nagoya University in 1996/97. Acceptance tests of its performance on carbon isotope measurements were completed in January of 1999, and routine measurements began in mid-2000. Since completion of the acceptance tests in early 1999, we have encountered a lot of troubles with the machine, particularly in 2002. Since the end of 2002, the machine has worked relatively well, expect for minor problems. The standard deviation (one sigma) of the 14C/12C ratio is around ±0.3% to ±0.4% (a bit larger than the uncertainty of about ±0.3% calculated from 14C counting statistics) and that of the corresponding 13C/12C ratio is ±0.03% to ±0.07%, as are tested for HOxII targets. The number of targets measured was 330, 1430, 2077, 1003, 1,979, 1679, 1772, 1115, 1339, 866, 1300, 1701, 1449, 1634, 1351, 1741, 1156 in each year from 1999 to 2015, respectively, and total number of targets measured by the end of 2015 is 23,921. We briefly describe the maintenance processes and application results of the AMS system in 2015. The Tandetron AMS system at Nagoya University worked rather well in 2015, with only minor failures, such as (1) X-Y direction movement trouble of target surface to change sputtering positions, (2) compressed-air-leakage problem of an air cylinder to exchange targets to be measured, (3) unexpected break down of high voltage of accelerator without any sparks, without any specific reasons, (4) ion source cleaning due to shortage of Cs in the container, (5) high temperature problem of the circulating water for cooling down the power supply system for two high-energy mass-analyzing magnets. The error no. (3) above became a serious problem at last in December, because we cannot reset a system diagnostic alarm concerning a high voltage spark at last. It was finally found out that the problem caused by a malfunction of the spark-detector circuit unit, mounted on the top of the accelerator tank. \In 2015, we also carried out many application programs of 14C measurements. The reports are included in this Proceedings volume., 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

Carbonate hydroxyapatite (CHa) in bone, which is a bone inorganic component, is beginning to be used for 14C dating on cremated bones, because the bones suffering from heat at the temperature of more than 600°C have high crystalline of apatite and are not easily contaminated by exogenous carbon. However, it remains a possibility that a part of carbon in CHa could be exchanged by exogenous carbon derived from fuel and/or atmosphere during heating. It is important, therefore, to reveal the origin of carbon in CHa for reliable 14C dating using CHa. The purpose of this study is to estimate the presence or absence of the possibility of capture of exogenous carbon into CHa during heating by investigating of changes of chemical composition and crystal structure of bones during heating. We conducted a heating experiment using two modem fresh boar bones. The F14C values of bone CHa did not change by heating, even when heating under atmosphere, while the δ13C values changed a little: decreased slightly with increasing heating temperature from 300°C to 750°C, and increased significantly at 900°C. The former decrease could be due to decomposition of carbonate with lower δ13C during heating, while the latter increase could be due to carbon isotopic fractionation and/or take-up of exogenous carbon. The results suggest the possibility of exchange of CHa carbon with carbon in fuel and/or atmosphere during heating., 火葬されて有機成分が残存していない骨に対し、骨の無機成分である炭酸ヒドロキシアパタイト(CHa)を用いた 14C年代測定が有効と考えられる。しかし、遺跡などから出土する火葬骨CHaのδ13C値が低いという報告があ り、火葬中に外来炭素を取り込んだ可能性も考えられる。そのため、加熱による骨の結晶構造や化学組成の変化を調べ、外来炭素の取り込みがないかを明らかにするこ とが、火葬骨CHaの14C年代の信頼性を議論する上で重要となる。本研究では、現生のイノシシ骨の加熱実験を行い、加熱による骨の結晶構造や化学組成の変化を調べた。その結果、大気存在下での加熱でも、骨CHaの14C濃度に変化は見られなかったが、δ13C値は 750℃まで加熱温度が高くなるにつれ減少し、900℃では増加した。しかし、その変化は1-2‰であり、Lanting et al. (2001)によ って報告されている低いδ13C値(-24±3‰)は今回の加熱実験では得られなかった。以上の結果か ら、骨を大気存在下で加熱することが、骨CHaのδ13C値を減少させる要因ではないこと、14C年代測定には影響しないことが明らかとなった。今後さらなる加熱実験を行い、骨CHaへの燃料中炭素の取り込みの有無について調べる予定である。, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

Speleothem 14C has recently emerged as a potentially powerful proxy for hydrology changes in comparison with atmospheric 14C calibration curve. Some possible causes for the relationship between speleothem 14C (or DCF: Dead Carbon Fraction) and karst hydrology have been proposed, such as changes in temperature, precipitation, and drip water flow dynamics. Minami et al. (2015) investigated 14C of drip water in Ryugashi Cave, Shizuoka Prefecture, central Japan, and reported that different DCF of drip water were exhibited at different sites, which had different temperature, air pCO2, and flow paths, and that the DCF in drip waters with conduit dominated flow paths could reflect rainfall amount around the cave. Accordingly, it is important to know DCF feature of drip water in advance on use of speleothem DCF as a terrestrial proxy for paleoenvironment and paleoclimate. Here, some DCF data of speleothems from Bahama, Hullu Cave, and Heshang Cave, and drip waters from Ryugashi Cave, Outaki Cave, and Gyokusen Cave, are compiled to understand the relationship between speleothem DCF and karst hydrology., 近年、石筍の14Cは、年代測定のツールとしてよりも、大気の14C較正曲線(IntCal14C曲線)と比較することにより、過去の水循環を知るための有効なプロキシとして注目を浴びている。石筍中の14Cは、石灰岩母岩に由来する14C-free(dead)炭素の混入によって希釈されており、この14C-free炭素の寄与率(DCF：Dead Carbon Fraction)は、気温の変化、降水量、滴下水の水系、洞内の換気状態、土壌大気のpCO2などの影響を受けて変化する。Minami et al.(2015)は、静岡県の竜ヶ岩洞の滴下水の14Cを測定し、滴下地点によって、滴下速度、Mg/Ca比、14C濃度が異なること、竜ヶ岩洞の滴下水は、水の通り道があり、降雨に反応する性質をもっていること、滴下水中の14Cは降水量と相関しており、降水量が多いと、滴下水中の14Cが高く(DCFが小さく)なる傾向があることを明らかにした。Bahama 石筍、Hulu Cave 石筍、Heshang Cave石筍の結果 も踏まえ、滴下水のDCFが小さい場合は、気候変動によってDCFがあまり 変動しないため、DCFが一定と して石筍の14C年代測定が可能であると予想できる。一方、DCFが大きい場合は、 気候変動(降水量)の影響を受けてDCFの値が変化するため、 正しい年代測定が難し い一方、IntCal14C曲線と比較することにより、古環境・古気候変動の情報を得るための有効な手段になると考えられる。, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

Eleven fossil shells and four charcoal samples collected from three sites of Ie Island, Okinawa were radiocarbon dated in order to determine ΔR value of Ie island. The ΔR values calculated for Nagarabaru-3 shell mound, Kayabaru-A site and Nagarabaru-east shell mound were 250±37 yr (n=2), 132±29 yr (n=5) and -37± 19 yr (n=2), respectively. The calibrated ages of above three sites using average ΔR value (115±29 yr) were 3,383±41 cal BP, 1,308±31 cal BP, and 1,492±27 cal BP, respectively., 伊江島南部のナガラ原第3貝塚，カヤ原遺跡A地点から採取し た合計9個の貝殻と2個の木炭，および木下(2013)が報告したナガラ原東貝塚の2個の木炭および2個の貝殻のAMS14C年代を使用して上記3遺跡のΔRを決定した。その結果，ナガラ原第三貝塚のΔRは650±37yr (n=2)および250±37yr (n=2)となり，カヤ原遺跡のΔRは132±29yr (n=5)となった。一方，ナガラ原東貝塚のΔRは37±19yr(n=2)となった。ナガラ原第三貝塚のΔR=650±37yrを異常値と判断し遺跡の較正年代の計算時に除外した。3個のΔRの平均値115±29yr (n=9)を使用して各遺跡の較正年代を計算した結果，ナガラ原第三貝塚は3,383±41calBP，カヤ原遺跡A地点は1,308±31calBP，そし てナガラ原東貝塚は1,492±27calBPとなった。, 名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告

Parker Volcano is classified as one of the active volcanoes in the Philippines and is located in the province of South Cotabato in southern Mindanao. The results of AMS radiocarbon (14C) dating for pyroclastic flow deposits of Parker Volcano are presented in this paper. A total of fourteen dates were obtained and are divided into five groups (i.e., 4 to 3.9 kBP, 1.9 kBP, 0.5 kBP, 0.4 to 0.3 kBP and 0.2 kBP), which are almost consistent with previous reported dates. To reveal its eruptive history in detail and with high precision, evaluation of these dates with geological and geomorphological framework is necessary. Moreover, results of this study can provide useful information for disaster risk reduction efforts., フィリピン共和国，ミンダナオ島のパーカー火山に分布する火砕流堆積物中の炭化木片の放射性炭素(14C)年代を加速器質量分析(AMS)法により測定した．得られた14C年代は，4～3.9, 1.9, 0.5, 0.4～0.3, 0.2kBPの5つのグループに区分される．ただし，最近500 年間にある3つのグループは近接しているため，今後，地形や地質層序を踏まえて詳細に検討する必要がある．今後，さらに研究を進めて噴火間隔(休止期間)と噴出物の分布(噴出量)が明らかになれば，火山災害の防止・軽減にも役立つものと期待される．, タンデトロン加速器質量分析計業績報告

Five drilling cores (AZK-101, AZK-2, AZK-3, AZK-4 and AZK-5) in the area Hamaatsuma to Kamiatsuma and four hand-operated drilling peat cores in the area Tomisato to Poronai along Azuma River, southern Hokkaido, were investigated based on lithologic observation, pollen analysis, diatom analysis, tephrochronology and AMS 14C dating. Consequently the authors revealed the existence of buried valley, and explained the vegetation and salinity change of the Upper Pleistocene to the Holocene deposits in the Azuma River area., 名古屋大学年代測定総合研究センターシンポジウム報告

It is well known that ages of ancient iron artifacts can be measured by using carbon contained in the iron artifacts. As a simple method of carbon extraction from iron artifacts, a normal quartz tube is used for metal iron combustion at the temperature of 1000℃ for about 15 hrs. We tested the quartz tube method of metal iron combustion successfully for metal iron in fine fragment forms and reported the results previously. In Japan, iron rust samples are commonly excavated from archeological sites of the Kofun period and after. We have tested to collect carbon from iron rust samples successfully by the quartz tube method of iron-rust combustion at 850℃ for 3 hr. We have experienced that quartz tubes were broken twice during combustion: at 900℃ for 8 hr and at 850℃ for 3 hr. 14C age, 524±25 BP, was obtained for an iron rust sample from a ruin of Fe manufacturing site worked at 1850s in Saga city, Saga Prefecture, Japan. The 14C age was too old compared with the estimated age of the site. 14C ages were also obtained for three rusty nail samples as 2949 -3244 BP. The results suggested a possibility of modern carbon contamination in considerable amount during rust process of metal iron that was produced by using coal as a heating fuel as well as material to reduce iron oxide ore., 名古屋大学年代測定総合研究センターシンポジウム報告

We have started a Radiocarbon lntercomparison on Chemical Experiments, Water series (RICE-W) program to examine whether carbon isotopic fractionation and carbon contamination occur or not on 14C analysis of dissolved inorganic carbon (DIC) in water by different sample preparation and storage methods. Eight water samples of four kinds (surface seawater, ground water, hot spring water, and sodium bicarbonate solution) have already analyzed by six AMS laboratories in Japan, and the results obtained are gradually being published. Here, we report the progress of RICE-W program briefly, and then give consideration to the result using the precipitation method, by which DIC is precipitated into SrCO3 or BaCO3, and then oxidized with H3PO4 to extract CO2., 我々は、研究機関による前処理法の違い等による水試料中の溶存無機炭素(DIC)の14C分析値のばらつきを比較・検討するため、水試料の14C比較プログラム(RICE-W: Radiocarbon Intercomparison onChemical Experiments，Water series)を立ち上げた。まず、予備的に採取したDIC濃度・塩濃度の異なる水試料(表層海水、温泉水、地下水、NaHC03水溶液)を6機関に配布し、各機関それぞれの化学前処理法によってDIC-14C分析を実施し、現在、得られた結果をもとに、RICE-Wプログラムの本格的始動に向けての基礎検証を行いつつある。本稿においては、RICE-Wプログラムの実施状況を簡単にまとめ、特に沈殿法(SrCl2やBaCl2を添加して炭酸塩を生成させた後、リン酸を添加してCO2を発生させる方法)による結果についてまとめた。その結果、塩濃度の高い水試料に沈殿法を用いた場合、沈殿剤(SrCl2、BaCl2)、pH調整剤(NH3、NaOH) によっては、沈殿が生成しにくい場合や、沈殿が生成しても炭素回収率が低い場合、そして現代炭素による汚染を受ける可能性があることが明らかとなり、沈殿法の最適な統一基準を設定する必要性が提示された。, 名古屋大学年代測定総合研究センターシンポジウム報告

Lake Baikal sediment cores record the paleoclimatic and biological changes in the continental area corresponding with the global and local climate changes. The global climate records, such as the Younger Dryas event, the Dansgaard-Oeshger cycles and the Heinrich events during the late Quaternary period, have been also observed from the Lake Baikal sediment core. However, the climate response corresponding with the melt water puls-19Ka (MWP-19Ka) has not been observed yet from the Lake Baikal sediment core. Here we show the rapid changes of the sedimentation rate in Lake Baikal sediment core (VER99G12) at around 19 cal ka BP, which were recovered from the 14C analysis of total organic carbon. The sampling site of VER99G12 is located in front of the Selenga River, which provides the largest inflow into the lake. Therefore, the sediment core in this study was mainly composed of the deposition from the Selenga River watershed. Radiocarbon measurements were carried out using the Tandetron AMS system (Model-4130, HVEE) in Center for Chronological Research, Nagoya University. High-time resolution 14C data sets from the sediment core revealed the rapid increase in sedimentation rate corresponding with the global climate warming (MWP-19Ka). The change of grain size and the K/Ti atomic ratios in the core also responded at the period as well. These results suggest the increase in the precipitation in the continental area at around 19000 years ago., 最終氷期最盛期(Last Glacial Maximum: LGM、26.5-19.0 ka, Clark et al., 2009) において、海水準は現在よりも最大約130m低下していたことが報告されている(Yokoyama et al., 2011)。海洋堆積物やサンゴの年代測定結果より、LGM以降から現在の海水準へ上昇するまでの間、急激な海水準上昇イベントが3度(約19,000年前、約14,500年前、約11,500年前)発生したと推定されている(Deschamps et al., 2012; Peltierand Fairbanks 2006; Yokoyama et al., 2000). 一方でこれらの急激な海水準上昇期に、大陸内部における水循環変動がどのように変化したかについては、未だ良く分かっていない.ユーラシア大陸南東部、シベリア地域に位置するバイカル湖は、その地理的特性から地球上で最も鋭敏に日射量変動を受ける地域に位置しており、バイカル湖の湖底堆積物を用いて、特に第四紀の大陸域における環境変動および生物活動変遷が復元されてきた(e.g. Horiuchi et al., 2000, Watanebe et al., 2004, Nara et al., 2014). 本研究では、バイカル湖から採取された堆積物試料(VER99G12、堆積物試料長さ466cm) を用いて、堆積速度の変化からLGM 以降における降水量変動の推定を行い、急激な海水準上昇期に対応した大陸域での降水量増加を明らかにした., 名古屋大学年代測定総合研究センターシンポジウム報告

Radiocarbon dates of wooden poles excavated from Nishigo archaeological site, and Yachi archaeological site, Niigata prefecture, Japan, were measured by accelerator mass spectrometry. The poles were also precisely dated with wiggle-matching using tree ring sequences sampled from the poles. As the results, the poles were dated ca. 380-210 calBC (Nishigo site) and ca. 1100-1030 calBC (Yachi Site). This result will support chronological research, especially in dendrochronology and oxygen isotopic dating., 新潟県新潟市に所在する西郷遺跡及び新潟県胎内市に所在する野地遺跡出土木柱の年代決定を目的として、木柱から採取した年輪試料のAMS14C年代測定とウイグルマッチングを行った。, 名古屋大学年代測定総合研究センターシンポジウム報告

Lithology and AMS14C ages of sediments accumulated in the dammed lake along the upper reach of the Sono River, Odai-cho, Mie Prefecture, central Japan are described at the two surface exposures and on the one drill core. The sediments are composed of bedded and laminated mud, silt and sand, top of which is covered by the debris flow deposits. Part of the laminations are interpreted as varves showing cyclic sedimentation of medium- to fine-grained clastic materials and very fine-graind clastics, algae, and siderite. Sporadic coarse-grained clastic interbeds showing graded bedding indicate the sedimentary events transporting the materials from the upper part of the basin by the turbidity corrents. The AMS 14C ages of wood fragments from the surface exposures range from 20440 to 20910 BP, while those from drill cores are from 21100 to 211900 BP. These ages indicate the sediment accumulation rate of the dammed lake is ca 20 mm/year., 地すべりにより形成された天然ダムは上流側にせき止め湖を形成する.三重県大台町の薗川上流では，過去のせき止め湖を埋積したせき止め湖堆積物が地表の2カ所で観察される.また，地表露頭の上流側で掘削したボーリングコアは，地表から深度約17mまでが土石流堆積物，その下位の深度約33mまでがせき止め湖堆積物からなる.せき止め湖堆積物は，層理・葉理の発達した泥層・シルト層からなり，砂層や礫質泥層を挟む.葉理の少なくとも一部は，砕屑粒子を含む粗粒部とシデライト濃集部を伴う細粒部からなり，年稿であると解釈できる.挟まれる粗粒層は級化層理を示し，上流部で発生したイベントによる堆積物と思われる.せき止め湖堆積物に含まれる木片の14C年代は，約20,000～22,000 BPで，せき止め湖堆積物の堆積速度は20mm/年程度と推定される., 名古屋大学年代測定総合研究センターシンポジウム報告

One of the important tasks of forensic science is characterization of the unidentified dead bodies produced accidently or criminally. These days, the estimation of the date of birth using bomb-produced 14C is almost established in the north Europe and the US. The most accurate age estimation is the method of using human teeth enamel. However, in Japan, such studies have not been carried out yet, because of the necessity of examination for zonal effect of 14C concentration and the difference of formation duration of teeth of the Japanese. This study intended to establish the age estimation using teeth of the Japanese, and measured 14C concentration of not only enamel but also collagen and inorganic matter of root of tooth. The 14C analysis of roots suggested that the formation of the inorganic matter continued a few years after that of the collagen. And, by using the 14C concentration of the root, the appropriate formation age ranges of enamel can be selected. Age estimation using teeth enamel can be conducted with an average error of 1.7±1.4 years. This value is as accurate as those obtained by the previous studies conducted in the north Europe and in the US. Age estimation using tooth of Japanese can be accurately conducted, and the result of this study assists with criminal investigation and forensic works in Japan to clarify the identity of unidentified cadavers., 法医学上，重要な目的の一つには，身元不明遺体の個人特定が挙げられる近年，核実験由来14Cを利用することでヒトの年齢推定を行う研究が北欧・北米で多く行われつつある.中でもヒト歯牙エナメル質中14Cを用いた誕生年推定は，±3年以内とかなりの高精度を誇る.しかしながら，日本においては，大気中14C濃度と日本人歯牙中14C濃度の間の差が明らかにされていないこと，人種による形成年齢の違いが存在することなどが原因で，このような研究は進展していない.本研究では，日本人歯牙を利用した誕生年推定法の確立を目指した.エナメル質に限らず，歯根中有機・無機成分の測定を行うことで，複数与えられるエナメル質形成年を1 つに絞り込む方法を提示した.エナメル質について，日本人の形成年齢を用い，実際の誕生年と推定誕生年の差を算出したところ，核実験期以降において，1.7±1.4年であった.これは，先行研究でのスウェーデン人，アメリカ人における値とほぼ同精度を示す値である.日本人歯牙中14Cを用いた人体年齢の精密推定は，高い精度で行えることが明らかになった.本研究の成果を利用することで日本における身元不明遺体の個人特定を目的とした科学捜査の際に，誕生年という非常に有用な情報が提供できる., 名古屋大学年代測定総合研究センターシンポジウム報告

The 27th symposium on age measurements with AMS (accelerator mass spectrometry) and EPMA (electron probe micro analyzer) systems, as well as their applications to geological and archeological samples, was opened on January 27th-28th, 2015, at Nagoya University. Symposium of this kind is held every year generally as an opportunity for users' meeting to publicize their results in utilizing the age-measurement facilities of the Center for Chronological Research (CCR), Nagoya University. In the symposium, the status reports of the AMS and EPMA systems were delivered firstly. Then, two reports were presented as the results of the program of the innovation of new technology and research for young scientists. Two special lectures were presented at the symposium: the first talk was entitled "Iron manufacture and circulation of iron products in ancient period on Japanese archipelago", given by Dr. Ryuhei Maruyama who retired from Faculty of Literature, Nagoya Women's University in 2009. He described a brief history on Japanese iron manufacturing and utilizing iron products in ancient period, and estimated that the first iron manufacture was conducted in the end of 6 century. The second talk entitled "The emplacement age of the Hikami granite, 440 Ma or 350 Ma? - A way to interpret incompatible age data" was given by Emeritus Professor Kazuhiro Suzuki who has retired from the Center for Chronological Research in 2012. He reviewed age data measured by K-Ar, CHIME, SHRIMP, Rb-Sr whole-rock isochron and LA-ICPMS U-Pb methods, and concluded that the southern Kitakami terrain is a Jurassic melange with granite, Silurian sediment and Devonian sediment as exotic blocks. This new concept will be submitted to the report in 2015 after further verification. Totally 22 oral reports and 3 poster reports were presented as contribution papers concerning the results on applications of the AMS as well as EPMA systems of the CCR. The fields of application are: study on solar activity based on 14C concentrations of tree rings; environmental applications, including human tooth analysis with 14C tracer; 14C dating analysis of charcoal and bone samples from archeological and cultural property samples; 14C dating study of paper documents; geological applications of 14C dating, including cored samples from Hokkaido; 14C dating application to cultural properties and archeological samples; studies on 14C calibration with Japanese wood; technical developments of sample preparation for 14C measurements; CHIME dating of monazite; technical study on CHIME dating for sub-micron sized samples. Finally, it should be noted that general participants who are not specialist of age measurements also joined the discussion and hopefully enjoyed it.

Charred material is widely used for radiocarbon (14C) dating in archaeological and palaeoenvironmental studies. Reliable 14C dating requires appropriate chemical treatment to remove post-deposition contamination, especially humic acid, from the charred material. This study compared two pre-treatment methods: Acid-Base-Acid (ABA) treatment and Acid-Base-Oxidation with Stepped-Combustion (ABOx-SC) treatment, in order to examine the effectiveness of decontamination. The ABA-treated environmental charcoal yielded younger 14C dates than the ABOx-treated samples, probably owing to the effects of remaining organic contaminants bound to the edges of the charred material's molecular structures, which were produced by the original pyrolysis. Oxidation treatment can preferentially remove humic acid contaminants, which remained after NaOH treatment. Therefore, the ABOx treatment can more effectively and efficiently remove exogenous humic acid than the ABA treatment. Furthermore, stepped combustion procedure can remove remained contaminants after chemical treatment, such as exogenous organic component and atmospheric CO2 absorbed during samples treatment. Therefore, the ABOx-SC treatment of the charcoal samples can lead a most reliable 14C age for the "old" (especially >30 ka) samples, which are susceptible to contaminants., 炭化物は14C年代測定の有力な試料であり、考古学ならびに古環境の分野で広く利用されている。信頼性のある14C年代を与えるには、炭化物が埋没中に取り込んだ外来炭素成分(特に腐植酸)を適切な試料処理で除く必要がある。本稿では、炭化物の試料処理の違いによる14C年代の違いについて報告する。同一埋没炭化樹木試料に対しABA法、ABOx法の化学処理を行った結果、ABA法では外来腐植酸が試料中に残存していること示唆された。これは炭化物分子に化学的に結合した形で試料中に存在する腐植酸はNaOH処理では除けないことによると考えられる。一方、二クロム酸カリウム溶液による処理を加えたABOx法では、NaOH処理後に残存した腐植酸を優先的に酸化分解するため、効果的かつ効率的に腐植酸を除去できると考えられる。段階加熱処理(SC処理)では、化学処理後に残存した外来有機成分ならびに一連の処理過程で取り込んだ可能性がある現代大気中CO2による汚染を除去する方法として有効と考えられる。したがって、僅かな外来炭素の汚染の影響を大きく受ける古い試料(特に3万年前以前の試料)において、ABOx法に段階加熱処理を加えたABOx-SC法は、外来炭素成分の除去法として最も有効であると言える。, 名古屋大学年代測定総合研究センターシンポジウム報告

Bone collagen, the organic fraction of the bone, is commonly used on 14C dating of bone, while it can not be used for cremated bone because of no remain of collagen. Meanwhile, recent studies have presented that carbonate hydroxyapatite (CHa), the inorganic fraction of the bone, can be used for 14C dating of cremated bone, though the CHa is easily contaminated by exogenous carbon and should be purified by chemical treatment. The purpose of this study is to test the reliability of 14C dating of CHa by using a cremated bone of known-age in Japan. The samples used were the cremated bone, which is considered to be remains of Jokei, a Buddhist monk (AD 1155-1213). We examined whether chemical treatment of the cremated bone with 0.1 M acetic acid for a short time of 1 hour is adequate for removal of secondary carbonate to obtain innate CHa for accurate 14C dating. The CHa in six fragments of the cremated bone showed 14C dates between 1155-1280 cal AD, which are similar with the supposed age. The result indicates the effectiveness of acetic acid treatment and the possibility of accurate 14C dating of CHa by the appropriate chemical treatment., 骨の14C年代測定には、有機成分であるコラーゲンを利用するのが一般的である。しかし、コラーゲンが損失しているため、14C年代測定が困難な骨試料も少なくない。そのような骨試料、特に火葬骨に対して、近年、無機成分の炭酸ヒドロキシアパタイト(CHa)を用いた14C年代測定が試みられている。そこで、本研究では、年代既知の火葬骨に対して、実際に、CHaを用いて信頼性のある14C年代測定が可能かどうかの検証を行った。また、二次的な炭酸塩による汚染を除去するための低濃度短時間の酢酸処理の有効性についても評価を行った。用いた火葬骨試料は、奈良県三郷町の持聖院に所蔵されていた蔵骨器内の骨片である。この人骨は、平安時代末から鎌倉時代にかけて活躍した僧・貞慶（AD1155-1213）の遺骨であるとされている。年代測定の結果、本研究で使用した火葬骨6点から得られた14C年代は1155-1280cal ADという、貞慶の没年と2σの誤差範囲で一致する結果となった。一方、酢酸処理により発生したC02は現代に近い年代を示したことから、本研究で使用した火葬骨は、2次的な炭酸塩等の外来炭素の汚染があったものの、酢酸処理によって効果的に除去された結果、CHaの信頼性のある14C年代測定が可能であったことがわかった。また、真空下における、0.1Mの酢酸による1時間程度の酸処理の有効性も明らかになった。今後、より年代の古い試料や保存状態の異なる試料についても検討を行っていく予定である。, 名古屋大学年代測定総合研究センターシンポジウム報告