@article{oai:nagoya.repo.nii.ac.jp:00016113,
 author = {Miyata, Yoshiki and 宮田, 佳樹},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {Using newly collected data combined with data from previous studies, we compared the measured radiocarbon ages of archaeological samples, which was the pair of the charred seed and molluscan shells, and terrestrial and aquatic animal bones around Lake Biwa, and of pine needles, Phragmites, and molluscan shells, collected in 1966, 1970, 1990 and 2008 at Lake Biwa in Japan, to examine freshwater reservoir effects at Lake Biwa. We also tested for age differences in radiocarbon dating among shell species, tissues and collected locations in the lake, to evaluate the influence for radiocarbon dating of archaeological samples in Lake Biwa. The molluscan shells collected after 1990 were largely unaffected by the nuclear testing that occurred in the 1950s and 1960s, whereas the 1966 and 1970 samples appeared to be affected by it, which make the reservoir ages older than expected. The shells collected after 1990 had radiocarbon ages that were 330-450 l4C years older than those of the coeval atmosphere. The apparent differences in radiocarbon age (about 300 14C years) for the pair of shell fossils and wood samples, and turtles and terrestrial mammals excavated from the same layer of the submerged Awazu shell midden at Lake Biwa suggest that the freshwater reservoir effect also existed in the middle Holocene (the Middle Jomon period, about 5000 years ago). Because the present-day average residence time of Lake Biwa water is less than a decade, its direct influence on the reservoir effect is small, which suggests that anyway old carbon has been supplied into Lake Biwa. To put it more concretely, there is the high possibility that the system as keeping the value of the freshwater reservoir effect in 300-450 14C years (steady state) function in Lake Biwa and then the closed Lake Biwa system has been in dynamic equilibrium state from 1950's up to the present, correspondingly enormous 14C input by atmospheric nuclear testing and its gradually decreasing. Based on the observe radiocarbon age difference between, for example of C. sandai at South Lake, the shell and meat of a shellfish the people living in Awazu submerged archeological site were thought to uptake the meat of C. sandai which were 75 ± 25 14C years younger than the hard shells and be, actually, 360 ± 25 14C years older than coeval atmosphere. When we try to reconstruct the paleodiets and paleoenvironments to use the radiocarbon dating in detail, it is very important to evaluate the radiocarbon age differences caused by shell species, tissues or collected locations and to be clear their influence for radiocarbon dating of archaeological samples., 本研究では､琵琶湖沿岸の粟津湖底第三貝塚から出土した､貝､獣骨や現生琵琶湖産魚貝試料の見かけ上の炭素年代差を見積もり､琵琶湖水に観察される淡水リザーバー効果の大きさの変遷を推定した｡その結果､縄文時代後期から大正までの琵琶湖水の淡水リザーバー効果の大きさに関する実測データはないが､琵琶湖周辺の石灰岩地帯や琵琶湖岸の泥炭層などに由来する古い炭素の影響によって,完新世後期のおよそ5000年間､琵琶湖水中の溶存無機炭素中の炭素14濃度は､300-45014cyrレベルのリザーバー効果を示す一定の値に保たれていた可能性が高いと推定される｡, 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},
 pages = {31--39},
 title = {Development of trace radiocarbon dating and its application : The radiocarbon age differences caused by shell species, tissues or collected locations and their application for reconstruction of paleoenvironment in Lake Biwa, Japan},
 volume = {23},
 year = {2012}
}