Timing of the Brunhes-Matuyama transition constrained by U-series disequilibrium.

ABSTRACT: U-series disequilibrium measurements carried out on thermogenic travertine samples from a 12.6 m-long core and a 10 m-thick section from southeastern Morocco yielded finite ages ranging from 500 ka to the present-day, as well as two clusters determined to be older than 500 ka. The calculation of initial ²³⁴U/²³⁸U activity ratios in all samples younger than 500 ka shows high, reasonably constant values, with an average of 5.172 ± 0.520 (one standard deviation). Assuming that this value prevailed for periods older than 500 ka, we derived ages of up to approximately 1.2 Ma using the initial ²³⁴U excess decay. Our results indicate that the two older clusters have ages of 776 ± 14 ka for samples from between 8 and 10.1 m and 1173 ± 22 ka for deeper samples respe

SUBMITTER: Ghaleb B 

PROVIDER: S-EPMC6465598 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature