High-precision dating of significant geologic phenomena in Post-Glacial age

高精度和高可靠性的放射性碳年代学是提高环境变化、地壳运动和人类进化分辨率的必要条件。这份放射性碳年代学将呈现出后冰期的清晰而精确的时空图像。为了实现这一年代学，并将其结果应用于更广泛的地区，在不同的地质背景下，我们引入了高精度的放射性碳测年与火山灰年代学。在广岛大学苯合成真空线上安装了超低本底液体闪烁β射线计数器。通过对苯的合成过程、同位素分馏过程和标准样品质量的仔细检查，新的放射性碳测年系统已经开始对冰后期的重要样品进行测年。野外对火山岩、古地震、海平面升降等进行了系统的测年样品采集、贯通检验和样品-事件关系研究。

High-precision and high-reliability radiocarbon chronology is necessary to improve the resolution of environmental change, crustal movement, and human evolution. This radiocarbon chronology will present clear and precise space-time images of the Post Glacial period. In order to realize this chronology and to apply the result to more extensive area in different geological context, we introduced high-precision radio carbon dating associated with tephrochronology. An super-low-background liquid scintillation beta-ray counter was installed together with benzene synthesis vacuum line in Hiroshima University. Through careful examination of the procedure of benzene synthesis, of isotopic fractionation, and of the quality of standard samples, the new radiocarbon dating system has begun to date important samples of Post Glacial period. In the field, systematic method for dating sample collection and through examination and sample-event relationship were carried out for tephras, paleoearthquakes, and sea-level fluctuation.