エジプトの西方砂漠に位置するハルガ・オアシスの窪地における利用水の14C年代

Beside the main research program of "Introduction of information technology into investigation of archeological site-El-Zayyan site in Egypt", the other program concerning water resources of oases in the western Egyptian desert was started at the time of the main program opening. According to the IFAO (International Federation for Artificial Organs) organization in Cairo, Egypt, archeological samples collected in Egypt are strictly prohibited to take out from Egypt for 14C dating. Radiocarbon dating program of Egyptian archeological samples in our research should be changed. Instead of archeological samples, we selected water samples, such as water for deep well, tap water, water for irrigation, and pet bottle water as well, to investigate how the water resources of oases in the Egyptian desert are composed. We conducted 14C dating on 12 water samples collected from Kharga oasis, Egypt, in 2007 and 2008. Such water samples as tap water, water for irrigation, which originate in the deep wells, showed 14C ages as old as 27,000 to 35,000 BP. Except for pet bottle water that was brought into the oasis areas from outside worlds, all water samples for living daily life are originated in deep well water. This tendency of using the water resources supplied from nearby areas is almost consistent with the water resource analysis in the Raqqa city, Syria, where the Euphrates river runs through the Raqqa city, and water from the Euphrates river is used mostly in the Raqqa area for daily life. For estimation of the time span for water flow from top area of Mt. Fuji to its foot, water sample was collected from the spring located at Oshino-hakkai area, Oshino, Minamitsuru, Yamanashi Prefecture, Japan. 14C age of dissolved inorganic carbon from the water sample that gushed out at the foot of Mt. Fuji was dated as 1129 ± 28 BP (NUTA2-14859), although the residence time of underground water that is flowing down on Mt. Fuji slopes has been estimated as a few tens of years, based on geological and geochemical analyses of the surface layers of Mt. Fuji and the water pass through the layers.