著者

三宅 芙沙 増田 公明 箱崎 真隆 中村 俊夫 門叶 冬樹 加藤 和浩 木村 勝彦 光谷 拓実 Miyake Fusa Masuda Kimiaki Hakozaki Masataka Nakamura Toshio Tokanai Fuyuki Kato Kazuhiro Kimura Katsuhiko Mitsutani Takumi

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

no.25, pp.137-143, 2014-03

---

Although some candidates for the cause of the mysterious cosmic ray event in AD 774-775 have been reported we were not able to specify. In order to investigate the occurrence rate of the 14C increase event like the AD 775 one, we measured 14C content in Japanese tree-rings during an extended periods. As a result,we detected the second 14C increase by significant amount from AD 993 to AD 994. From the occurrence rate (one 14C event/800 years),it was revealed that a large-scale SPE is the most plausible explanation for the 14C event. 775年の宇宙線イベントの原因について、いくつかの候補が挙がっていたが特定するのは難しい状況であった。本研究の年代を拡張した14C濃度測定により、993-994年にかけても似たような14C急増を発見した。また、994年イベントは日本産の2個体の樹木から存在を確認した。14Cイベントの発生頻度から、その原因として大規模SPEが妥当であると考えられる。見つかった14Cイベントの14C増加量は、観測史上最大のSPEの1O~数10倍に相当する。このような規模のSPEが仮に今日発生した場合、現代社会へ深刻な被害を及ぼすと想定される。今回の発見はこうした大SPEが将来において発生する可能性を示したものである。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

著者

三宅 芙沙 増田 公明 箱崎 真隆 中村 俊夫 門叶 冬樹 加藤 和浩 木村 勝彦 光谷 拓実 Miyake Fusa Masuda Kimiaki Hakozaki Masataka Nakamura Toshio Tokanai Fuyuki Kato Kazuhiro Kimura Katsuhiko Mitsutani Takumi

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.25, pp.137-143, 2014-03 (Released:2015-05-12)

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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

著者

中村 俊夫 宇田津 徹朗 田崎 博之 外山 秀一 杉山 真二 松田 隆二 Nakamura Toshio Udatsu Tetsuro Tazaki Hiroyuki Toyama Shuichi Sugiyama Shinji Matsuda Ryuji

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.24, pp.123-132, 2013-03 (Released:2014-06-09)

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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

著者

鈴木 和博 中村 俊夫 南 雅代 池田 晃子 Suzuki Kazuhiro Nakamura Toshio Minami Masayo Ikeda Akiko

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.22, pp.121-134, 2011-03

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Japanese Red foxes (Vulpes vulpes japonica) establish stable home ranges within particular areas or are itinerant with no fixed abode around human habitations. They are popular wild animals and feature prominently in the folklore of human culture. The population, however, was decreased until the beginning of the 1970's, and no fox has been seen since about 1975 in Kodenosawa, a small habitation about 17km NE from the urban area of Toyota City. A fox remains was found from the under floor of the Jizo-temple together with a ragged package of Nissin Chicken-Ramen which was used from 1971 to 1983. The fox's remains is c. 50 cm in body length. The left half of the remains exhibits soft tissues including skin and dried muscle, but the right half facing to the ground is completely decayed. To determine when the fox died, we measured 14C concentration in collagen extracted from a tooth and a rib of the remains. The δ13C (-18±1 ‰) normalized 14C concentrations are 129.2±0.4 pMC for the tooth and 129.0±0.4 pMC for the bone. Although the values intersect the calibration curve at 1962 and 1979, the 1979 age only agrees with the time span supported by the envelope of Chicken-Ramen. Drying of muscle tissue without rotting was likely to take place in cold winter. Thus, the fox's death is reasonably definable in the period from late November 1979 to early January 1980. The δ13C (-18±1‰) values suggest a diet containing a significant amounts of C4 food or protein with higher isotopic values. There is little C4 plants in Kodanosawa, but sizable amounts of cone were constantly brought from outside for cow's and chicken's food. A possible protein source is the herbivore and the omnivorous feeder within the area. An alternative may be marine fish and the derivatives including dog- and cat-food. To test whether the fox took food brought from outside or not, we analyzed the 87Sr/86Sr isotopic ratio of the remains. The 87Sr/86Sr isotopic ratios, 0.709439±0.000016 for the tooth and O.749464±0.000014 for the bone, are distinctly lower than those of wild boar's bone (0.709944±0.000016 and 0.709912±0.000012), river water (0.710079±0.000016) and the granite (0.710218±0.00016) that underlies the wide area of Toyota City. The initial 87Sr/86Sr ratio of 0.7096±0.0001 constrains the lowest isotopic ratio of water, plants and animals within the area. The distinctly lower 87Sr/86Sr values documents that the fox took sizable external food with higher δ13C values. After the disappearance of foxes from Kodenosawa around 1980, wild boars swelled in population. Voracious scavengers dug slope of hills side and paddy fields as they foraged for bulbs, yams, earthworms and grubs, and eventually ate voraciously paddy, sweet potatoes and beans in the field. This triggered the abandonment of cultivation of fields that face mountains. It is likely presumed that foxes were preventing wild boars from invading the human habitation through attacking Uribou, young wild boars. 愛知県豊田市小手沢町にある地蔵堂を建替えるために旧堂を取壊したとき,床下から乾潤びたキ ツネの遺骸が見つかった.遺骸の横に1971年から1983年まで使用されたデザインのチキンラーメ ンの袋があった. 口先から骨盤までの長さが約50cmの成獣である.遺骸の地面に接した右側半分 と尾は骨まで溶けて失われていた.左側半分には耳や皮膚も腐敗することなく保存されていたが, 体毛は全く残っていなかった.骨は白骨化し,前足の付け根の皮膚にのみ黒色の筋組織様のものが 付着していた. キツネの歯と骨から抽出したゼラチンコラーゲンの14C濃度(δ13C=-25‰に規格化)は129.2±0.4 pMCと129.0土0.4pMCである.この較正年代(1962年と1979 -1980) 年)とチキンラーメン袋の 使用期間および腐敗の無いことを総合して,キツネの死亡時期を1979年11月下旬~1989年1月上 旬と特定した.キツネのδ13Cは=-18±1‰である.小手沢地内にはC4植物が殆ど栽培されていない ので, 地域内の植物や小動物のみを食べていたと仮定すると,ほぼ完全な肉食をしない限りδ13C=-18‰にならない.一方,キツネの87Sr/86Sr比は0.70745 であり,分析誤差を超えて小手沢のイノシ シ(0.70993) ・川の水(0.71008) ・花崗閃緑岩の初生値(0.7096)より小さい. δ13C値と87Sr/86Sr比か ら,キツネは外来の餌(残飯を含む人間の食料やトウモロコシ主体の家畜飼料)を相当量摂取して いたと結論した. 地蔵堂の床下から見つかったキツネの死亡時期(1979年)は,小手沢地内でキツネが減少した時期 より約10年後で,イノシシの食害が顕在化する1980年代半ばに近い.人家に近い里山を縄張りと するキツネが,イノシシの人里進出を阻止していた可能性を考察した.第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告

著者

鈴木 和博 中村 俊夫 南 雅代 池田 晃子 Suzuki Kazuhiro Nakamura Toshio Minami Masayo Ikeda Akiko

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.22, pp.121-134, 2011-03

---

Japanese Red foxes (Vulpes vulpes japonica) establish stable home ranges within particular areas or are itinerant with no fixed abode around human habitations. They are popular wild animals and feature prominently in the folklore of human culture. The population, however, was decreased until the beginning of the 1970's, and no fox has been seen since about 1975 in Kodenosawa, a small habitation about 17km NE from the urban area of Toyota City. A fox remains was found from the under floor of the Jizo-temple together with a ragged package of Nissin Chicken-Ramen which was used from 1971 to 1983. The fox's remains is c. 50 cm in body length. The left half of the remains exhibits soft tissues including skin and dried muscle, but the right half facing to the ground is completely decayed. To determine when the fox died, we measured 14C concentration in collagen extracted from a tooth and a rib of the remains. The δ13C (-18±1 ‰) normalized 14C concentrations are 129.2±0.4 pMC for the tooth and 129.0±0.4 pMC for the bone. Although the values intersect the calibration curve at 1962 and 1979, the 1979 age only agrees with the time span supported by the envelope of Chicken-Ramen. Drying of muscle tissue without rotting was likely to take place in cold winter. Thus, the fox's death is reasonably definable in the period from late November 1979 to early January 1980. The δ13C (-18±1‰) values suggest a diet containing a significant amounts of C4 food or protein with higher isotopic values. There is little C4 plants in Kodanosawa, but sizable amounts of cone were constantly brought from outside for cow's and chicken's food. A possible protein source is the herbivore and the omnivorous feeder within the area. An alternative may be marine fish and the derivatives including dog- and cat-food. To test whether the fox took food brought from outside or not, we analyzed the 87Sr/86Sr isotopic ratio of the remains. The 87Sr/86Sr isotopic ratios, 0.709439±0.000016 for the tooth and O.749464±0.000014 for the bone, are distinctly lower than those of wild boar's bone (0.709944±0.000016 and 0.709912±0.000012), river water (0.710079±0.000016) and the granite (0.710218±0.00016) that underlies the wide area of Toyota City. The initial 87Sr/86Sr ratio of 0.7096±0.0001 constrains the lowest isotopic ratio of water, plants and animals within the area. The distinctly lower 87Sr/86Sr values documents that the fox took sizable external food with higher δ13C values. After the disappearance of foxes from Kodenosawa around 1980, wild boars swelled in population. Voracious scavengers dug slope of hills side and paddy fields as they foraged for bulbs, yams, earthworms and grubs, and eventually ate voraciously paddy, sweet potatoes and beans in the field. This triggered the abandonment of cultivation of fields that face mountains. It is likely presumed that foxes were preventing wild boars from invading the human habitation through attacking Uribou, young wild boars. 愛知県豊田市小手沢町にある地蔵堂を建替えるために旧堂を取壊したとき,床下から乾潤びたキ ツネの遺骸が見つかった.遺骸の横に1971年から1983年まで使用されたデザインのチキンラーメ ンの袋があった. 口先から骨盤までの長さが約50cmの成獣である.遺骸の地面に接した右側半分 と尾は骨まで溶けて失われていた.左側半分には耳や皮膚も腐敗することなく保存されていたが, 体毛は全く残っていなかった.骨は白骨化し,前足の付け根の皮膚にのみ黒色の筋組織様のものが 付着していた. キツネの歯と骨から抽出したゼラチンコラーゲンの14C濃度(δ13C=-25‰に規格化)は129.2±0.4 pMCと129.0土0.4pMCである.この較正年代(1962年と1979 -1980) 年)とチキンラーメン袋の 使用期間および腐敗の無いことを総合して,キツネの死亡時期を1979年11月下旬~1989年1月上 旬と特定した.キツネのδ13Cは=-18±1‰である.小手沢地内にはC4植物が殆ど栽培されていない ので, 地域内の植物や小動物のみを食べていたと仮定すると,ほぼ完全な肉食をしない限りδ13C=-18‰にならない.一方,キツネの87Sr/86Sr比は0.70745 であり,分析誤差を超えて小手沢のイノシ シ(0.70993) ・川の水(0.71008) ・花崗閃緑岩の初生値(0.7096)より小さい. δ13C値と87Sr/86Sr比か ら,キツネは外来の餌(残飯を含む人間の食料やトウモロコシ主体の家畜飼料)を相当量摂取して いたと結論した. 地蔵堂の床下から見つかったキツネの死亡時期(1979年)は,小手沢地内でキツネが減少した時期 より約10年後で,イノシシの食害が顕在化する1980年代半ばに近い.人家に近い里山を縄張りと するキツネが,イノシシの人里進出を阻止していた可能性を考察した.

著者

三宅 芙沙 増田 公明 箱崎 真隆 中村 俊夫 門叶 冬樹 加藤 和浩 木村 勝彦 光谷 拓実 Miyake Fusa Masuda Kimiaki Hakozaki Masataka Nakamura Toshio Tokanai Fuyuki Kato Kazuhiro Kimura Katsuhiko Mitsutani Takumi

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.25, pp.137-143, 2014-03

---

Although some candidates for the cause of the mysterious cosmic ray event in AD 774-775 have been reported we were not able to specify. In order to investigate the occurrence rate of the 14C increase event like the AD 775 one, we measured 14C content in Japanese tree-rings during an extended periods. As a result,we detected the second 14C increase by significant amount from AD 993 to AD 994. From the occurrence rate (one 14C event/800 years),it was revealed that a large-scale SPE is the most plausible explanation for the 14C event. 775年の宇宙線イベントの原因について、いくつかの候補が挙がっていたが特定するのは難しい状況であった。本研究の年代を拡張した14C濃度測定により、993-994年にかけても似たような14C急増を発見した。また、994年イベントは日本産の2個体の樹木から存在を確認した。14Cイベントの発生頻度から、その原因として大規模SPEが妥当であると考えられる。見つかった14Cイベントの14C増加量は、観測史上最大のSPEの1O~数10倍に相当する。このような規模のSPEが仮に今日発生した場合、現代社会へ深刻な被害を及ぼすと想定される。今回の発見はこうした大SPEが将来において発生する可能性を示したものである。

著者

窪田 薫 白井 厚太朗 杉原 奈央子 清家 弘治 棚部 一成 南 雅代 中村 俊夫 Kubota Kaoru Shirai Kotaro Sugihara-Murakami Naoko Seike Koji Tanabe Kazushige Minami Masayo Nakamura Toshio

出版者

名古屋大学宇宙地球環境研究所

雑誌

名古屋大学年代測定研究

巻号頁・発行日

vol.2, pp.1-6, 2018-03-31

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Mercenaria stimpsoni (Stimpson's hard clam), found in shallow sandy seafloor of northeast Japan, has been proved to have longevity of more than 100 years, which is the longest record in Japan. The present study established nuclear bomb testing induced bomb-14C records from M. stimpsoni shells, for the first time in high latitude western North Pacific, in which chronology is robustly constrained from a synchronized annual growth width pattern among individuals. The record revealed a strong influence of Tsugaru Warm Current on shallow water of northeast Japan. Furthermore, age-determination of dead shells collected from the seafloor of the study region by utilizing the established bomb-14C records suggests that past tsunamis are one of the most important reasons of death of M. stimpsoni.東北日本(岩手県大槌)から見つかった二枚貝の一種ビノスガイ(Mercenaria stimpsoni)は100歳を超す寿命を持ち,日本産の二枚貝としては最長寿であることが最近明らかになった.本研究では,ビノスガイの殻を用いて,複数個体間で同期した年間成長パターンをもとに厳密な年代モデルを構築し,東北地域としては初となる核実験起源の放射性炭素曲線を復元した.その結果,三陸沖の浅海域においては,津軽暖流(対馬海流を起源とする)の影響が強く見られることがわかった.さらに,得られた放射性炭素曲線を大槌の海底から得られた死殻の死亡年代の推定に用いることで,過去の津波イベントがビノスガイの死を招く重要な要因になっている可能性が示された.

著者

中村 俊夫 NAKAMURA Toshio

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.22, pp.23-36, 2011-03 (Released:2011-03-00)

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第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告

著者

中村 俊夫 NAKAMURA Toshio

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.15, pp.103-112, 2004-03

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Accurate knowledge on marine reservoir effect is particularly important to estimate active periods of archeological sites in Japan. Since most of archeological sites are situated in an alluvial plain in Japan, archeological remains include inevitably marine products. To obtain precise calendar ages for marine samples such as shell fragments and sea mammal bones by ^<14>C dating, a correction for marine reservoir effect is necessary. In addition, ^<14>C ages on a collagen fraction extracted from human bones should be corrected for the sources of their diet, the uptake ratio of terrestrial food to marine one. However, the local fluctuation of marine reservoir effect around Japan Islands is not known well. This study gives a brief summary of a calibration method for ^<14>C ages of samples containing marine-derived carbon.

著者

中川原 育子 谷口 陽子 佐藤 一郎 中村 俊夫 NAKAGAWARA Ikuko TANIGUCHI Yoko SATO Ichiro NAKAMURA Toshio

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

no.23, pp.127-137, 2012-03

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The Kizil Grottoes, the largest Buddhist monastery complex in the Xinjian region of China, is decorated with wall paintings - the chronological dates of which are still under debate. This study aims to give some clarification regarding the chronological dates using AMS-14C dating of chaff tempers taken from the earthen renders of the wall paintings. l4C studies previously carried out by Chinese and German researchers had resulted in divergent dates often extending back hundreds of years earlier than hypothesized within the chronology of art history, which has created confusion. Six samples from six wall painting fragments (Caves 8 [III8425], 38 [III8700], 171 [III8793, III8891], 207[III9148b(d)], and 224[III8865(a)]) held in collections at the Museum für Asiatische Kunst in Berlin were taken and analysed with 14C-AMS at the Center of Chronological Research at Nagoya University in Japan. As reference, nine dating results analysed between 1995 and 1998 at Nagoya University were also shown in the list. Dates were obtained for only three out of the six samples: cal AD 128-216 [Cave 8], cal AD 255-306 and cal AD 312-34 [Cave 171], and 90-70 cal BC [Cave 224]; most of these extended back earlier than reference 14C data from the Chinese and German studies and far earlier than dates suggested by the timeline of art history. Even the Chinese and German reference dates derived in the past from 14C analysis often show varied dates occurring earlier than those represented in art history. This may indicate that old chaff was used in renders for the Kizil wall paintings probably as a form of re-use of old mud bricks, or that the chronology of art history must be drastically reconsidered, both of which would require further AMS-14C dating studies with careful and comprehensive sampling from well-documented contexts.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

著者

中村 俊夫 宇田津 徹朗 田崎 博之 外山 秀一 杉山 真二 松田 隆二 Nakamura Toshio Udatsu Tetsuro Tazaki Hiroyuki Toyama Shuichi Sugiyama Shinji Matsuda Ryuji

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.24, pp.123-132, 2013-03

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To measure 14C age directly on plant opal itself with accelerator mass spectrometry (AMS), we have extracted carbon contained in plant-opal samples separated from modern lining plants as well as ancient soil deposits at archeological sites, in particular, rice field remains. Carbon dioxide was separated and collected from plant-opal samples by using a radio-frequency furnace (HF-1O, Leco Corporation) which is used successfully to extract carbon in the metal iron. Carbon content of plant opal is not clearly known, and yields of CO2 from p1ant-opal samples were very low (<0.1%) in our experiment Nagoya University AMS 14C dating laboratory. We have conducted CO2 extraction for 15 samples, and we can get enough CO2 from only three samples to perform 14C dating even with AMS. The obtained 14C ages were a few thousand years older than expectations on the basis of archeological aspects. Even more, plant-opal samples extracted from modern living plants showed 14C ages as old as 3-6 ka BP. This implies that carbon in plant opal is not derived from carbon incorporated into the plants by photosynthesis. More studies are required to apply routinely 14C dating of plant-opal material.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

著者

鈴木 和博 Suzuki Kazuhiro 中村 俊夫 Nakamura Toshio 加藤 丈典 Kato Takenori Takenori 池田 晃子 Ikeda Akiko 後藤 晶子 Goto Akiko 小田 寛貴 Oda Hirotaka 南 雅代 Minami Masayo 上久保 寛 Kamikubo Hiroshi 梶塚 泉 Kajizuka Izumi 足立 香織 Adachi Kaori 壺井 基裕 Tsuboi Motohiro 常磐 哲也 Tokiwa Tetsuya 太田 友子 Oota Tomoko 西田 真砂美 Nishida Masami 江坂 直子 Esaka Naoko 田中 敦子 Tanaka Atsuko 森 忍 Mori Shinobu ダンクリー ダニエル Dunkley Daniel J. クシャク モニカ Kusiak Monika A. 鈴木 里子 Suzuki Satoko 丹生 越子 Niu Etsuko 中崎 峰子 Nakazaki Mineko 仙田 量子 Senda Ryoko 金川 和世 Kanagawa Kazuyo 熊沢 裕代 Kumazawa Hiroyo

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.19, pp.26-38, 2008-03

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Umi is located along the Kamimura River within the Kamiyahagi area of southeastern Ena City, Gifu Prefecture. The name 'Umi' means sea or large lake; however, there are no lakes in the mountainous Kamiyahagi area. The Tokai Gou (torrential rain) flood of September 11-12, 2000 destroyed embankments along the river, and exposed sedimentary layers that are typical of a lacustrine depositional setting. This confirms the existence of a paleo-lake from which the name Umi originated. The ^<14>C ages, ranging from 280±37 to 345±25 BP, appear to be contemporaneous with Tensho Earthquake that occurred in central Japan on January 18, 1586.

著者

椋本 ひかり 南 雅代 中村 俊夫 Mukumoto Hikari Minami Masayo Nakamura Toshio

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

no.26, pp.96-101, 2015-03

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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

著者

椋本 ひかり 南 雅代 若木 重行 中村 俊夫 Mukumoto Hikari Minami Masayo Wakaki Shigeyuki Nakamura Toshio

出版者

名古屋大学宇宙地球環境研究所年代測定研究部

雑誌

名古屋大学年代測定研究

巻号頁・発行日

no.1, pp.102-107, 2017-03-31

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Bones exposed to temperatures of more than 600℃ become to possess the high crystallinity of apatite, which protects them against easy contamination. This property now makes it possible to use the carbonate hydroxyapatite (CHa), an inorganic component of bone, for the 14C dating of cremated bones. Other chemical characteristics, such as Sr/Ca and δ88Sr, indicators of trophic levels and/or dietary preferences, are also expected to be preserved in cremated bones. This study was conducted to examine whether the CHa in cremated bones can provide accurate 14C dates and reliable information on diet. Cremated bone fragments from an urn at the Jisho-in Temple in Nara Prefecture, Japan were used as the sample. These bones are thought to be the remains of Jokei, a Buddhist monk (AD 1155–1213). The CHa in two fragments, which have high crystallinity, was determined to have a 14C date of 1040–1220 cal AD (±2σ), a date similar with the presumed age. The log(Sr/Ca) and δ88Sr values obtained from the bone CHa were –2.79 and from –0.140 to –0.125, respectively, values similar to those of herbivores (log(Sr/Ca)= –3.0~–2.5; Balter et al., 2002, δ88Sr =–0.30±0.17‰; Tütken et al., 2015). This finding is consistent with Jokei's dietary custom of not eating meat. The results of this study demonstrate the effectiveness of using CHa in cremated bones for the 14C dating of bones and dietary analysis.最近の研究により、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(Carbonate Hydroxyapatite: CHa)を用いた14C年代測定の有効性が実証された(Lanting et al., 2001; Zazzo et al., 2011)。CHaは、高温(>600℃)で加熱されると結晶化が進み埋没後に続成作用の影響を受けにくくなることがその理由として挙げられる。そのため、結晶性の高いCHaを含む火葬骨は、生体由来の化学成分を保持でき、栄養段階の指標であるSr/Ca値やδ88Sr値などを分析することにより、14C年代だけでなく食性に関する情報も復元できることが期待できる。そこで、本研究では、仏教徒「貞慶」(AD1155-1213)の遺骨とされる火葬骨のSr/Ca値及びδ88Sr値の分析を行い、貞慶が菜食であったことを実証できるかどうかを検討した。結晶性の高い火葬骨のCHaから得られた14C年代値は貞慶の没年(1213年)と矛盾しない結果であった。さらに、log(Sr/Ca)値は-2.79、δ88Sr値は-0.14~-0.13であり、いずれも草食動物の値(log(Sr/Ca)=-3.0~-2.5; Balter et al., 2002、δ88Sr値=-0.47~-0.13; Tütken et al., 2015))の範囲であった。この結果は、貞慶が菜食主義であったことを示すものであり、考古学的な見解と一致している。これらの結果から、高温で加熱され、結晶性が高い火葬骨CHaは、生体由来のSr/Ca値及びδ88Sr値を保持しており、年代に関する情報だけでなく生前の食習慣を探るのにも有効であることが明らかになった。本研究は、日本学術振興会科学研究費補助金挑戦的萌芽研究[骨の炭酸ヒドロキシアパタイトを用いた炭素14年代測定の試み」(代表者:南雅代、課題番号26560144)の助成を受けて行なわれました。

著者

佐野 貴司 Sano Takashi 和田 秀樹 Wada Hideki 海野 進 Unimo Susumu 中村 俊夫 Nakamura Toshio

出版者

名古屋大学年代測定資料研究センター 天然放射性元素測定小委員会

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.3, pp.67-75, 1992-03

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We obtained radiocarbon datings of 29,209±554 yrBP. for shell sample from Pukaki and 30,230±413 yrBP. for that from Motukorea in the Auckland Volcanoes, New Zealand. When we supply the ages of indivisual volcanoes and compositional change with time, it can be possible to elucidate the magma system of the Auckland Volcanic Field.

著者

渡邊 隆広 WATANABE Takahiro 奈良岡 浩 NARAOKA Hiroshi 西村 弥亜 NISHIMURA Mitsugu 中村 俊夫 NAKAMURA Toshio 仙田 量子 SENDA Ryoko 河合 崇欣 KAWAI Takayoshi

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.15, pp.199-205, 2004-03 (Released:2010-06-03)

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タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 2003 (平成15)年度

著者

中村 俊夫 宇田津 徹朗 田崎 博之 外山 秀一 杉山 真二 松田 隆二 Nakamura Toshio Udatsu Tetsuro Tazaki Hiroyuki Toyama Shuichi Sugiyama Shinji Matsuda Ryuji

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.24, pp.123-132, 2013-03

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To measure 14C age directly on plant opal itself with accelerator mass spectrometry (AMS), we have extracted carbon contained in plant-opal samples separated from modern lining plants as well as ancient soil deposits at archeological sites, in particular, rice field remains. Carbon dioxide was separated and collected from plant-opal samples by using a radio-frequency furnace (HF-1O, Leco Corporation) which is used successfully to extract carbon in the metal iron. Carbon content of plant opal is not clearly known, and yields of CO2 from p1ant-opal samples were very low (<0.1%) in our experiment Nagoya University AMS 14C dating laboratory. We have conducted CO2 extraction for 15 samples, and we can get enough CO2 from only three samples to perform 14C dating even with AMS. The obtained 14C ages were a few thousand years older than expectations on the basis of archeological aspects. Even more, plant-opal samples extracted from modern living plants showed 14C ages as old as 3-6 ka BP. This implies that carbon in plant opal is not derived from carbon incorporated into the plants by photosynthesis. More studies are required to apply routinely 14C dating of plant-opal material.

著者

南 雅代 Minami Masayo 中村 俊夫 Nakamura Toshio 平田 和明 Hirata Kazuaki 長岡 朋人 Nagaoka Tomohito 鵜澤 和宏 Hoshino Keigo

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.18, pp.134-143, 2007-03

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During the past several decades, many medieval skeletons were excavated from archaeological sites in the Yuigahama area, Kamakura, Japan. The excavations yielded more than 5,000 individuals in varying states of preservation from the Zaimokuza, Seiyokan, Yuigahama-minami and Chusei Shudan Bochi sites. Medieval Kamakura was an ancient capital of the Kamakura Shogunate, and a lot of people lived in Kamakura with high population density. The human skeletons excavated from the Zaimokuza site are reported to be humans dead by competition at the end of the Kamakura Shogunate, but a detailed study on dating of the human skeletons has not made yet. In this study, we measured ^<14>C ages, together with carbon and nitrogen isotope ratios, of human skeletal remains excavated from the Yuigahama-minami site and Chusei Shudan Bochi site. The δ^<13>C and δ^<15>N were not different between human skeletal samples of both sites, while the ^<14>C ages were different between them: The human bones of the Yuigahama-minami site are 100 year younger than those of the medieval collective-cemetery site. All of ages of human skeletons from both of the sites are older than the latest Kamakura period. The δ^<13>C and δ^<15>N values of the medieval Kamakura people are higher than those of terrestrial mammals, indicating that they exploited some amount of marine fish and/or mammals with higher δ^<13>C and δ^<15>N as protein sources. Therefore, the ^<14>C ages obtained for human skeletons could be order than the true ages. ^<87>Sr/^<86>Sr isotopic ratios of human skeletons of the Yuigahama-minami site tend to be higher than those of the Chusei Shudan Bochi site. Soils, plants and animals feeding on them in a given locality have ^<87>Sr/^<86>Sr values that generally mirror underlying bedrock composition, and thus ^<87>Sr/^<86>Sr ratios of human skeletons are useful tools for assessing migration in prehistory. The result obtained in this study suggests that Yuigahama-minami humans and Chusei Shudan Bochi humas lived in different areas. More skeleton samples should be analyzed for determining detailed ^<14>C ages of humans excavated from the Yuigahama sites, and for estimating migration of prehistory of the medieval Kamakura humans.

著者

宮原 ひろ子 Miyahara Hiroko 毛受 弘彰 Menjo Hiroaki 桑名 宏輔 Kuwana Kousuke 増田 公明 Masuda Kimiaki 村木 綏 Muraki Yasushi 中村 俊夫 Nakamura Toshio

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.16, pp.57-64, 2005-03

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This paper presents the variation of solar activity during the Maunder Minimum (1645-1715 AD) deducted from radiocarbon content in tree-rings. Radiocarbon is produced by the galactic cosmic rays, which are modulated by the solar wind and the interplanetary magnetic field in the heliosphere. The production rate of radiocarbon, therefore, reflects the state of solar magnetic activity. Most distinct index of solar magnetic activity it the group sunspot number. The variations of sunspot number have shown clear cyclicity since the 18^<th> century with average length being about eleven years. The sunspots, however, have once almost disappeared during the period of 1645-1715 AD due to extraordinary weakening of solar activity. This period has been called as the Maunder Minimum. There is no remarkable cyclicity in the sunspot variations. We, therefore, investigated the cyclicity of radiocarbon content in tree rings from the Maunder Minimum in order to clarify the characteristics of solar activity during this period. We compared two radiocarbon records obtained newly by our group and by Stuiver et al. The results of frequency analyses have shown that solar magnetic reversals had maintained through the Maunder Minimum and that the length of the "eleven-year" cycle was stretched to 13-15 years.

著者

中村 俊夫 太田 友子 山田 哲也 Nakamura Toshio Ohta Tomoko Yamada Tetsuya

出版者

名古屋大学年代測定資料研究センター

雑誌

名古屋大学加速器質量分析計業績報告書

巻号頁・発行日

vol.26, pp.150-155, 2015-03

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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