“死碳”对14C年代测定影响的初步研究

在回顾14C测年技术发展的基础上,指出了影响14C测年精度的各种因素,并初步讨论了"死碳"对14C年代的影响.通过对岩溶区"死碳"的成因分析以及对碳酸盐样品的14C年代学研究,认为酸的来源不同,是造成岩溶区样品14C年代偏老的原因;局部环境中"死碳"释放是造成水生样品14C表观年龄偏老的主要原因.由于影响岩溶区样品14C年龄的因素是多方面的,目前尚无有效的校正办法.为此,作者在讨论了洞穴碳酸盐样品年代的可靠性及影响因素的基础上,提出了用交叉对比定年的方法解决"死碳"对14C测年的影响问题和在岩溶地区谨慎使用14C年龄的建议.

STUDY ON THE AFFECTION OF DEAD CARBON TO 14C DATING

Based on the advance of ~(14)C dating technology, the factors that will affect the accuracy of ~(14)C dating are pointed out and the affection of the dead C to ~(14)C dating is discussed preliminarily in this paper. Through analyzing the cause of formation of dead carbon in karst area and ~(14)C chronology in carbonate samples, it is believed that the ~(14)C age of the samples in karst area is older than the actual age,which is caused by the difference of the acid formation, and that the apparent age of the aquatic samples is older than the actual age,which is caused mainly by the releasing of dead carbon at local area. As many reasons affect the ~(14)C age of the samples in karst area, there is no way to revise the deviation at present. After many years' study on ~(14)C dating to cave carbonate samples in karst area, the authors bring forward crossing dating to solve the problem and suggest that it is necessary to be careful to use ~(14)C age of this kind of sample.