Pb-loss-aware Eruption/Deposition Age Estimation

C. Brenhin Keller

Geochronology Discussions (preprint, not yet peer reviewed), 2023:

Code and Data    

Interpreting overdispersed crystallization and closure age spectra has become a problem of significant import in high-precision geochronology. While Bayesian eruption age estimation appears to provide one promising avenue for the statistical interpretation of such dispersed datasets, existing methods critically hinge on an assumption of fully closed-system behavior after the time of eruption. However, given the presence of two independent decay systems with distinct responses to open-system behavior, the U/Pb system provides in principle the possibility of quantifying and potentially even constraining the timing of Pb-loss. Here we present a method for Pb-loss-aware eruption age estimation, that explicitly models not only the duration of crystallization but also the timing and magnitude of Pb-loss given accurate 206Pb/238U and 207Pb/235U isotopic ratios and covariances, leading to eruption age estimates that are potentially robust to post-eruptive Pb-loss. Further applications to detrital zircon data are considered.

Suggested citation:
Keller, C.B. “Pb-loss-aware Eruption/Deposition Age Estimation.” Geochronology Discussions 2023 (2023): 1-13.