Articles | Volume 7, issue 4
https://doi.org/10.5194/gchron-7-459-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gchron-7-459-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
10 Oct 2025
Research article |
| 10 Oct 2025
| 10 Oct 2025
Carbonate 206Pb ∕ 238U problems and potential 207Pb ∕ 235U fixes
Dept. of Earth Sciences, University College London, London, WC1E 6BT, UK
Noah McLean
Dept. of Geology, University of Kansas, Lawrence, KS 66045, United States
Anton Vaks
Geological Survey of Israel, 9692100 Jerusalem, Israel
Tzahi Golan
Geological Survey of Israel, 9692100 Jerusalem, Israel
Sebastian F. M. Breitenbach
Dept. of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
Randall Parrish
Dept. of Geography and Geosciences, University of Portsmouth, Portsmouth, PO1 3QL, UK
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Manuscript not accepted for further review
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A novel technique for the uranium–lead dating of geologically young carbonates is described and tested. The technique expands our ability to date geological events such as fault movements and past climate records.
Cited articles
Albarède, F.: Introduction to Geochemical Modeling, Cambridge University Press, https://doi.org/10.1017/CBO9780511622960, 1995. a, b
Bateman, H.: The solution of a system of differential equations occurring in the theory of radio-active transformations, Proc. Cambridge Phil. Soc., 15, 423–427, 1908. a
Cheng, H., Edwards, R. L., Shen, C.-C., Polyak, V. J., Asmerom, Y., Woodhead, J., Hellstrom, J., Wang, Y., Kong, X., Spötl, C., Wang, X., and Calvin Alexander, E.: Improvements in 230Th dating, 230Th and 234U half-life values, and U–Th isotopic measurements by multi-collector inductively coupled plasma mass spectrometry, Earth Planet. Sc. Lett., 371, 82–91, 2013. a
Danišík, M., Schmitt, A. K., Stockli, D. F., Lovera, O. M., Dunkl, I., and Evans, N. J.: Application of combined U-Th-disequilibrium/U-Pb and (U-Th)/He zircon dating to tephrochronology, Quat. Geochronol., 40, 23–32, 2017. a
Farley, K., Kohn, B., and Pillans, B.: The effects of secular disequilibrium on (U–Th)/He systematics and dating of Quaternary volcanic zircon and apatite, Earth Planet. Sc. Lett., 201, 117–125, 2002. a
Fleischer, R. L.: Alpha-recoil damage and solution effects in minerals: uranium isotopic disequilibrium and radon release, Geochim. Cosmochim. Ac., 46, 2191–2201, 1982. a
Horstwood, M. S., Košler, J., Gehrels, G., Jackson, S. E., McLean, N. M., Paton, C., Pearson, N. J., Sircombe, K., Sylvester, P., Vermeesch, P., Bowring, J. F., Condon, D. J., and Schoene, B.: Community-Derived Standards for LA-ICP-MS U-(Th-)Pb Geochronology – Uncertainty Propagation, Age Interpretation and Data Reporting, Geostand. Geoanal. Res., 40, 311–332, 2016. a
Jaffey, A., Flynn, K., Glendenin, L., Bentley, W., and Essling, A.: Precision measurement of half-lives and specific activities of 235U and 238U, Phys. Rev. C, 4, 1889–1906, 1971. a
Kaufman, A. and Broecker, W.: Comparison of Th230 and C14 ages for carbonate materials from Lakes Lahontan and Bonneville, J. Geophys. Res., 70, 4039–4054, 1965. a
Le Roux, L. J. and Glendenin, L. E.: Half-life of 232Th, Proceedings of the National Meeting on Nuclear Energy, Pretoria, South Africa, 5–8 April 1963, https://lccn.loc.gov/89460516 (last access: 8 October 2025), 1963. a
Ludwig, K. R.: Effect of initial radioactive-daughter disequilibrium on U-Pb isotope apparent ages of young minerals, J. Res. US Geol. Surv., 5, 663–667, 1977. a
Ludwig, K. R.: On the treatment of concordant uranium-lead ages, Geochim. Cosmochim. Ac., 62, 665–676, https://doi.org/10.1016/S0016-7037(98)00059-3, 1998. a, b, c
Ludwig, K. R.: Mathematical–statistical treatment of data and errors for 230Th
Nuriel, P., Wotzlaw, J.-F., Ovtcharova, M., Vaks, A., Stremtan, C., Šala, M., Roberts, N. M. W., and Kylander-Clark, A. R. C.: The use of ASH-15 flowstone as a matrix-matched reference material for laser-ablation U–Pb geochronology of calcite, Geochronology, 3, 35–47, https://doi.org/10.5194/gchron-3-35-2021, 2021. a, b, c
Pollard, T., Woodhead, J., Hellstrom, J., Engel, J., Powell, R., and Drysdale, R.: DQPB: software for calculating disequilibrium U–Pb ages, Geochronology, 5, 181–196, https://doi.org/10.5194/gchron-5-181-2023, 2023. a, b, c, d
Porcelli, D. and Swarzenski, P. W.: The behavior of U-and Th-series nuclides in groundwater, Rev. Mineral. Geochem., 52, 317–361, 2003. a
Roberts, N. M. W., Drost, K., Horstwood, M. S. A., Condon, D. J., Chew, D., Drake, H., Milodowski, A. E., McLean, N. M., Smye, A. J., Walker, R. J., Haslam, R., Hodson, K., Imber, J., Beaudoin, N., and Lee, J. K.: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb carbonate geochronology: strategies, progress, and limitations, Geochronology, 2, 33–61, https://doi.org/10.5194/gchron-2-33-2020, 2020. a
Smith, P. E. and Farquhar, R. M.: Direct dating of Phanerozoic sediments by the 238U–206Pb method, Nature, 341, 518–521, 1989. a
Vaks, A., Bar-Matthews, M., Matthews, A., Ayalon, A., and Frumkin, A.: Middle-Late Quaternary paleoclimate of northern margins of the Saharan-Arabian Desert: reconstruction from speleothems of Negev Desert, Israel, Quaternary Sci. Rev., 29, 2647–2662, 2010. a
Vaks, A., Woodhead, J., Bar-Matthews, M., Ayalon, A., Cliff, R., Zilberman, T., Matthews, A., and Frumkin, A.: Pliocene–Pleistocene climate of the northern margin of Saharan–Arabian Desert recorded in speleothems from the Negev Desert, Israel, Earth Planet. Sc. Lett., 368, 88–100, 2013b. a
Vermeesch, P.: Unifying the U–Pb and Th–Pb methods: joint isochron regression and common Pb correction, Geochronology, 2, 119–131, https://doi.org/10.5194/gchron-2-119-2020, 2020. a, b, c
Vermeesch, P.: Errorchrons and anchored isochrons in IsoplotR, Geochronology, 6, 397–407, https://doi.org/10.5194/gchron-6-397-2024, 2024. a, b
Vermeesch, P.: Data and code for “Carbonate
Vermeesch, P., Hopley, P., Roberts, N., and Parrish, R.: Geochronology of Taung and other southern African australopiths, in: One hundred years of Australopithecus africanus, edited by Wood, B. A., Grine, F. E., and Smith, H. B., Springer, Chap. 4, EarthArXiv, https://doi.org/10.31223/X5DB43, 2025. a, b
Walker, J., Cliff, R. A., and Latham, A. G.: U–Pb isotopic age of the StW 573 hominid from Sterkfontein, South Africa, Science, 314, 1592–1594, 2006. a
Woodhead, J., Hellstrom, J., Maas, R., Drysdale, R., Zanchetta, G., Devine, P., and Taylor, E.: U–Pb geochronology of speleothems by MC-ICPMS, Quat. Geochronol., 1, 208–221, 2006. a
Zhou, J., Lundstrom, C. C., Fouke, B., Panno, S., Hackley, K., and Curry, B.: Geochemistry of speleothem records from southern Illinois: Development of (234U)
Short summary
U–Pb dating of cave sediments has provided important new time constraints on the evolution of cave-dwelling organisms (including early humans) and of Earth's climate during the past 5 Myr. This paper shows that the most common type of U–Pb dating, which uses 238U and 206Pb, can be inaccurate beyond ca. 2 Myr ago. It proposes an alternative type of U–Pb dating, using 235U and 207Pb, as a more accurate alternative.
U–Pb dating of cave sediments has provided important new time constraints on the evolution of...
