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

摘要

Calculations, according to some open-system models, point out that while a statistically significant discrepancy between the results of two U-series methods, ~(230)Th/~(234)U and ~(227)Th/~(230)Th (or ~(231)Pa/~(235)U), 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 geo-chemical 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.