Chemical U-Th-Pb geochronology: A precise explicit approximation of the age equation and associated errors

Geochronometria

Gavril Săbău¹ 

[1] Geological Institute of Romania

关键词: U-Th-Pb chemical dating;    age equation;    explicit approximation;   

DOI  :  10.2478/s13386-012-0007-3

学科分类：社会科学、人文和艺术（综合）

来源: Politechnika Slaska * Instytut Fizyki

【 摘 要 】

In a single decaying system, the age determined from the exponential decay law is directly related to its linear Maclaurin approximation. This relationship can be additively extended to several decaying systems resulting in the same daughter element, by using proportionality functions, thus allowing an explicit formulation of the age as a function of element concentrations. The values of the binary proportionality function for the 238U-235U-Pb system and the ternary proportionality function for the 232Th-238U-235U-Pb system were determined by iterations of the exponential decay formula up to 4 Ga, with a step of 10 Ma, for a set of 24 different U/Th ratios. From the iteration data, the expressions of the two functions and the associated coefficients were determined by polynomial regression and mathematical programing on conveniently separated time and compositional intervals.

【 授权许可】

Unknown