海洋沉积物14C测年数据整合与校正问题探讨

随着放射性碳(14C)测年技术的发展,海洋沉积物年代学已成为研究古环境和古气候变化的重要手段。文章从14C测年数据整合角度,辨析和厘定了放射性碳测年有关术语及相互关系,探讨了数据校正的关键环节,制定了14C测年数据整合格式。测年数据整合格式应包括站位信息、样品测试信息、测年方法信息和校正方法信息等,其中惯用年龄是核心要素,而校正方法选择及与之相关的参数的使用是获得正确年龄的关键。采用CALIB7.0对选取的24个不同时期、不同实验室样本数据进行了统一校正,整合前后结果对比分析表明,软件不同版本或不同方式校正结果有数十年至一千多年的差异。14C日历校正年龄与惯用年龄大小、标准校正曲线、校正软件以及海洋储库年龄(R(t))或区域海洋储库校正值(ΔR)有关,建议资料整合时在惯用年龄基础上选择适合的校正软件重新对数据进行统一校正。同时,应加强我国近海海洋放射性碳储库年龄的研究,为测年数据校正提供更为准确的校正参数。

A DISCUSSION OF MARINE SEDIMENTS 14C DATA INTEGRATION AND CORRECTION

With the development of radiocarbon(14C) dating technique, marine sediment chronology has become one of the major methods for researching the paleoclimate and paleoenvironment change.From the perspective of 14C data integration, this paper determined the radiocarbon dating terms and their correlated relations, and discussed the key steps of 14C data correction, and this paper made the 14C dating data standard format, which would benefit to the normalization of 14C dating results.The format should contain information on stations, samples test, dating and correlation techniques et al., among which the conventional age is the core factor and the choice of correlation approach and corresponding parameters is key to obtaining correct ages.24 typical data from different periods and different laboratories were selected to be calibrated by CALIB 7.0.The comparison and analysis of results before and after the integration showed that there were differences of decades to one thousand years among the results from different versions of software or different ways of calibration.The 14C calibrated age was related to the conventional 14C age, standard calibration curve, calibration program and radiocarbon marine reservoir age(R(t)) or regional marine reservoir correction value(ΔR).We suggest that while performing data integration, suited correction program should be selected to recalibrate the data uniformly on the basis of conventional ages.Meanwhile, the research on radiocarbon marine reservoir data from nearshore and offshore area in China should be strengthened, which would provide more accurate parameters for 14C dating correction.