Articles | Volume 1, issue 1
Research article
26 Sep 2019
Research article |  | 26 Sep 2019

Resolving the effects of 2-D versus 3-D grain measurements on apatite (U–Th) ∕ He age data and reproducibility

Emily H. G. Cooperdock, Richard A. Ketcham, and Daniel F. Stockli

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Cited articles

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Bargnesi, E. A., Stockli, D. F., Hourigan, J. K., and Hager, C.: Improved accuracy of zircon (U – Th)/ He ages by rectifying parent nuclide zonation with practical methods, Chem. Geol. 426, 158–169,, 2016. 
Beucher, R., Brown, R. W., Roper, S. Stuart, F., and Persano, C.: Natural age dispersion arising from the analysis of broken cystals: Part II. Practical application to apatite (U-Th)  He thermochronometry, Geochim. Cosmochim. Ac., 120, 395–416,, 2013. 
Blott, S. J. and Pye, K.: Particle shape: a review and new methods of characterization and classification, Sedimentology, 55, 31–63,, 2008. 
Brown, R. W., Beucher, R., Roper, S. Persano, C., Stuart, F., and Fitzgerald, P.: Natural age dispersion arising from the analysis of broken crystals. Part I: Theoretical basis and implications for the apatite (U-Th)  He thermochronometer, Geochim. Cosmochim. Ac., 122, 478–497,, 2013. 
Short summary
(U–Th) / He chronometry relies on accurate grain-specific size and shape measurements. Using > 100 apatite grains to compare assumed 2-D versus true 3-D grain shapes measured by a microscope and X-ray computed tomography, respectively, we find that volume and surface area both differ by ~ 25 % between the two techniques and directly affect mass and concentration measurements. But we found a very small effect on the FT correction (2 %) and no discernible impact on mean sample age or dispersion.