Work

Evaluating 14 C and 14 C / 10 Be terrestrial age dating systems for meteorites using experimental data and model calculations

Year: 2025

Type: article

Abstract: This study presents a refined approach to determine 14 C saturation activities and 14 C/ 10 Be saturation activity ratios in chondritic meteorites with the goal to improve terrestrial age dating. By combining new model calculations for 10 Be, 14 C, and cosmogenic ( 22 Ne/ 21 Ne) cos , along with experimental data from 17 freshly fallen chondrites, we established reliable correlations for 14 C production rates and 14 C/ 10 Be production rate ratios as a function of ( 22 Ne/ 21 Ne) cos . The experimental data agree with the model calculations, and they fully confirm that 14 C production rates and 14 C/ 10 Be production rate ratios depend on shielding. Constrained correlations describe the experimental data for all shielding conditions and all ordinary chondrites mostly within the uncertainties given by the model. The new correlations therefore provide a significant improvement compared to the earlier approaches, in which average meteorite‐type‐dependent 14 C production rates and average 14 C/ 10 Be production rate ratios were assumed. Ignoring the shielding dependence introduces a size‐dependent bias into the terrestrial age database. This study enables the determination of shielding‐corrected 14 C saturation activities and 14 C/ 10 Be production rate ratios to calculate shielding‐corrected terrestrial ages for meteorites reducing or eliminating a size bias in the database. In addition, this novel approach enables to give reliable uncertainty estimates of within 15% for the 14 C and 14 C‐ 10 Be terrestrial ages.

Source: Meteoritics and Planetary Science

DOI: 10.1111/maps.14355