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We, the members of the Division for Chronological Research at the Institute for Space-Earth Environmental Research at Nagoya University, held a regional contribution program for the higher grade elementary school students on August 3–4, 2017: “Investigation of natural and environmental history in the Tokai region”. Twenty-seven students observed natural samples to experience earth and archaeological sciences. The first day began with lectures on tephra chronology and dendrochronology. After the lecture, the students took part in several hands-on experiments by using tephra and annual tree rings. On the second day they travelled to Shizuoka by bus and visited the Museum of Natural and Environmental History, Shizuoka to study natural and environmental history in the Tokai region. Later in the day they went to Miho no Matsubara to observe the states of coastal erosion and pine wilt disease. Finally, they went to Nihondaira to study about a movement of the earth’s crust. The program ended a success. The post-program questionnaire shows that the participants enjoyed the program and learned many new things., 宇宙地球環境研究所年代測定研究部は，静岡県ふじのくに地球環境史ミュージアムの山田和芳教授，菅原大助准教授，静岡大学理学部の北村晃寿教授と協力し，平成29年8月3日（木）と4日（金）の2日間にわたり，小学高学年生27名を対象とした夏休み体験学習「東海の地球環境史を学ぼう」を行いました．教室での講義だけでは得られ難い実体験の機会は，子どもたちの科学への興味や関心をより高めるきっかけになり，本体験学習の目的は十分達成できたと考えられる．

An AMS system (Model 4130-AMS) dedicated to 14C measurements, built by High Voltage Engineering (HVE), B.V., the Netherlands, was delivered to Nagoya University in 1996/97. Acceptance tests of its performance on carbon-isotope-ratio measurements were completed in January of 1999, and routine measurements began in mid-2000. The number of targets measured was 330, 1430, 2077, 1003, 1,979, 1679, 1772, 1115, 1339, 866, 1300, 1701, 1449, 1634, 1351, 1741, 1156, 466 and 900 in each year from 1999 to 2017, respectively, and total number of targets measured by the end of December 2017 is 25,287. We briefly describe the maintenance processes of the AMS system in the year of 2017. The Tandetron AMS system at Nagoya University has encountered several problems in 2017. They are; (1) two big sparks seriously damaged the solid state RF driver for the high voltage generation, and the AMS system could not supply the high voltage of 2.5 MV used for 14C measurements. We replaced a damaged coil at the final part of the high-voltage power supply unit with a new coil; (2) a power supply unit for loading electrical current to correctly adjust the current for the recombinator magnet was in trouble. A resistance unit located at the end of current supply circuit was burnt out. We replaced it to a new one; (3) after a high-voltage spark, we could not apply high voltage to the accelerator. A control circuit board of supplying high voltage was checked and it was found out that the electrical board B-5-41-205-0001 was out of work. We replace the board to one repaired previously; (4) During the usual measurement of a graphite target, 12C3+, 13C3+ and 14C3+ decreased gradually in the last half of its measurement time of 30 minutes. The plus ion beam intensity of 13C3+ decreased from 200nA to 5nA in ten minutes, without any changes on its target current (corresponding to 13C- current). We first checked all the parameter values of the power supplies to the AMS system, but we could not find any changes from their nominal values. We finally concluded that something wrong has happened inside the accelerator tank, and decided to open the tank after 5 years of previously opening the tank. Owing to these problems, we can process only 900 graphite targets in 2017. In 2017, we also have carried out some application programs of 14C measurements at Nagoya University. Some of the results are included in this Proceedings volume.

Burned bones may not provide accurate 14C dating because of no remain of collagen, an organic fraction in bone, suffered from heating. It is a very crucial assignment to enable burned bone to be 14C-dated. The purpose of this study is to test the reliability of 14C dating of carbonate hydroxyapatite (CHa), an inorganic fraction in bone, by using some burned bones from archaeological sites. The samples tested are five burned bones with gray to black colors of known-age collected from the Göytepe and Damjili Cave archeological sites in Azerbaijan. The XRD patterns of the bones showed that they had not suffered from the heat of >600ºC, and that they have low crystallinity of apatite. The 14C dates of the Göytepe and Damjili Cave bones were younger than the dates obtained by charred materials excavated from the same layer for 400 years and 1000–1700 years, respectively. The results indicate that the bones burned at the low temperature (, 遺跡に埋没している被熱骨に対し，炭酸ヒドロキシアパタイトを用いて信頼性のある14C年代測定が可能であるかを検証した．用いた試料は，アゼルバイジャンのギョイテペ遺跡とダムジリ洞窟遺跡から出土した被熱動物骨7点である．これらの骨試料の炭酸ヒドロキシアパタイトの14C年代は，同層から得られた炭化植物片の年代よりも，ギョイテペ遺跡においては400年，ダムジリ洞窟遺跡においては1000-1700年程度若くなった.XRDパターン結果から，二次的に付着した炭酸塩は，試料の酢酸処理によって除去されていると考えられ，若くなった原因は，炭酸ヒドロキシアパタイト結晶内に入り込んだ汚染炭素によるものと考えられる．ギョイテペ遺跡とダムジリ洞窟遺跡遺跡による年代差は，ギョイテペ遺跡の周辺は火成岩が，ダムジリ洞窟の周辺は石灰岩が分布していて土壌環境が異なっていたためと考えられる．今後さらに，埋没環境，被熱温度が異なる骨試料に対し，炭酸ヒドロキシアパタイトを用いて信頼性のある14C年代を得るための検討を行なっていく必要がある．