放射性碳素测定年代报告（四一）

The present report publishes the chronological data of 26 specimens dated by the 14C Laboratory of the Center for Scientific Archaeology, IA, CASS and Xi＇ an Accelerator Mass Spectrometry （AMS） Center, Institute of Earth Environment, Chinese Academy of Sciences （CAS）, from 2011 to 2013. These data were calculated with the half life of 14C as 5568 years; the program for calibrating the data was the OxCal3.10 version and the margins of error of the dates were ± 1 6 and ± 2 6, the probability distributions of the dates corresponding to which were 68.2% and 95.4%, respectively. The data were all calibrated with the data of δ 13C. These specimens came from Xichengyi Site in Zhangye City, Gansu Province.