U—Series Dating of Fossil Bones：Results from Chinese Sites and Discussions on Its Reliability

Calculations,according to some open-system models,point out that while a statistically significant discrepancy between the results of two U-series methods,^230Th/^234U and ^227Th/^220Th(or ^231Pa/^235U),attests a relatively recent and important uranium migration,concordant dates cannot guarantee closes-system behavior of sample.The results of 20 fossil bones from 10 Chinese sites,19 of which are determined by two U-series methods,are given,Judging from independent age controls,8 out of the 11 concordant age sets are unacceptable,The results in this paper suggest that uranium may cycle into or out of fossil bones,such geochemical events may take place at any time and no known preserving condition may securely protect them from being affected.So for the sitew we have studied,the U-series dating of fossil bones is of limited reliability.

U-series dating of fossil bones: Results from Chinese sites and discussions on its reliability

Calculations, according to some open-system models, point out that while a statistically significant discrepancy between the results of two U-series methods,²³⁰Th/²³⁴U and²²⁷Th/²³⁰Th (or²³¹Pa/²³⁵U), attests a relatively recent and important uranium migration, concordant dates cannot guarantee closed-system behavior of a sample. The results of 20 fossil bones from 10 Chinese sites, 19 of which are determined by two U-series methods, are given. Judging from independent age controls, 8 out of the 11 concordant age sets are unacceptable. The results in this paper suggest that uranium may cycle into or out of fossil bones, such geochemical events may take place at any time and no known preserving condition may securely protect them from being affected. So for the sites we have studied, the U-series dating of fossil bones is of limited reliability. This project was jointly supported by the Chinese National Education Committee and the Science and Technology Committee of Guizhou Province.