Abstract Recent research has demonstrated the importance of understanding alpha radiation damage in zircon in order to effectively interpret the thermochronologic significance of (U-Th)/He dates and to appropriately select laser ablation U/Pb reference standards. Direct measurements of alpha radiation damage in zircon are most easily done by using Raman spectral response as a proxy. Current Raman microscopes provide the opportunity to quantify not just a crystal's bulk radiation damage, but to map intracrystalline variations in radiation damage related to radionuclide zoning. Here we illustrate the procedure through a detailed study of zoned Proterozoic zircon crystals from the Adirondack Mountains of New York state. Although previous Raman studies have focused on the response of the v3(SiO4) stretching band (1008 cm−1) to radiation damage, we demonstrate that the internal v2(SiO4) bending band (439 cm−1) and the external Eg band (357 cm−1) are in some cases more useful – and in the case of the Eg band more responsive – proxies. We present curves that permit α dose estimates to be made from Eg and v2 band widths over a range of ~2 × 1017 to 1.8 × 1018 α/g. We then illustrate how these radiation damage maps can be used to visualize and interrogate intracrystalline variations in any damage-dependent material property in zircon, using helium diffusivity as an example, and discuss the implications for (U-Th)/He and U/Pb chronology of ancient, zoned zircon.

中文翻译：

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使用拉曼光谱绘制锆石中的辐射损伤分区：对锆石年代学的影响

Abstract Recent research has demonstrated the importance of understanding alpha radiation damage in zircon in order to effectively interpret the thermochronologic significance of (U-Th)/He dates and to appropriately select laser ablation U/Pb reference standards. 通过使用拉曼光谱响应作为代理，最容易直接测量锆石中的 α 辐射损伤。当前的拉曼显微镜不仅可以量化晶体的整体辐射损伤，还可以绘制与放射性核素分区相关的辐射损伤的晶内变化图。在这里，我们通过对来自纽约州阿迪朗达克山脉的分区元古代锆石晶体的详细研究来说明该过程。尽管之前的拉曼研究集中在 v3(SiO4) 伸缩带 (1008 cm-1) 对辐射损伤的响应上，我们证明了内部 v2(SiO4) 弯曲带 (439 cm-1) 和外部 Eg 带 (357 cm-1) 在某些情况下更有用 - 在 Eg 带的情况下更具响应性 - 代理。我们呈现的曲线允许在 ~2 × 1017 至 1.8 × 1018 α/g 的范围内从 Eg 和 v2 带宽进行 α 剂量估计。然后，我们以氦扩散率为例说明这些辐射损伤图如何用于可视化和询问锆石中任何损伤相关材料特性的晶内变化，并讨论对 (U-Th)/He 和 U/Pb 的影响古代分区锆石的年表。我们呈现的曲线允许在 ~2 × 1017 至 1.8 × 1018 α/g 的范围内从 Eg 和 v2 带宽进行 α 剂量估计。然后，我们以氦扩散率为例说明这些辐射损伤图如何用于可视化和询问锆石中任何损伤相关材料特性的晶内变化，并讨论对 (U-Th)/He 和 U/Pb 的影响古代分区锆石的年表。我们呈现的曲线允许在 ~2 × 1017 至 1.8 × 1018 α/g 的范围内从 Eg 和 v2 带宽进行 α 剂量估计。然后，我们以氦扩散率为例说明这些辐射损伤图如何用于可视化和询问锆石中任何损伤相关材料特性的晶内变化，并讨论对 (U-Th)/He 和 U/Pb 的影响古代分区锆石的年表。