Zircon crystals frequently comprise discrete growth zones, each of which may preserve temporal information on different geological processes. However, discrete growth domains can be below the spatial resolution of the applied analytical technique, resulting in composite isotopic ratios when mixed during sampling. Here, we develop a technique to rapidly extract meaningful core model ages, including propagated uncertainties, from core–rim mixtures when the rim age is constrained. A Python-based program with a graphical user interface is provided to facilitate easy application of this approach. We demonstrate the efficacy of this procedure on a detrital sample from the East Greenland Caledonides, where >90% of analyses were unavoidable core–rim mixtures. Metamorphic rim analyses yield a ²⁰⁶Pb/²³⁸U age of 418 ± 7 Ma (2σ), overlapping within error of the crystallization age of nearby granitoids (426 ± 1 Ma; 2σ). Using this rim age, we recover dates of detrital cores from core–rim mixtures. Model assumptions include original core concordance and a lack of isotopic disturbance at any time other than the rim age, but such assumptions can be validated and a metric of model reliability is provided. Reconstructed detrital core age populations are statistically indistinguishable from those of nearby equivalent metasedimentary rocks. We caution against the use of this technique without checking the appropriateness of the underlying assumptions but provide chemical means to evaluate the assumptions (e.g., alpha dose). The unmixing approach provides a mechanism to determine core ages from core–rim mixtures to recover additional information for addressing geological questions.

锆石晶体通常包含不连续的生长带，每个生长带可以保存有关不同地质过程的时间信息。但是，离散的生长域可能低于所应用分析技术的空间分辨率，导致在采样过程中混合时的复合同位素比率。在这里，我们开发了一种技术，可以在限制轮辋年龄的情况下，从轮辋-边缘混合物中快速提取有意义的核心模型年龄，包括传播的不确定性。提供了带有图形用户界面的基于Python的程序，以简化此方法的应用。我们证明了该方法对东格陵兰东部喀里多尼德斯碎屑样品的有效性，其中超过90％的分析是不可避免的岩心-岩浆混合物。变质边缘分析得出²⁰⁶ Pb / ²³⁸U年龄为418±7 Ma（2σ），在附近花岗岩的结晶年龄误差（426±1 Ma;2σ）内重叠。使用这个边缘年龄，我们从岩心-边缘混合物中恢复碎屑岩心的日期。模型假设包括原始核心一致性以及除边缘年龄以外的任何时间都没有同位素扰动，但是可以验证这些假设并提供模型可靠性的度量。从统计上看，重建的碎屑岩芯年龄种群与附近的同沉积沉积岩没有区别。我们警告不要使用此技术，而无需检查基础假设的适当性，但要提供化学手段来评估这些假设（例如，α剂量）。