The accuracy and validation of geo- and thermochronological dating hinges on the availability of well-characterised age reference materials. The Mesoproterozoic gabbroic anorthosite FC1 from the Duluth Complex, Minnesota is a reference material for zircon U-Pb and a suggested reference material for apatite fission-track dating. We evaluate FC1 as (U-Th)/He reference material, and determine its apatite U-Pb, and zircon and apatite (U-Th)/He age. Our dating results constrain the thermal history of FC1, showing that fast cooling occurred between ~ 1099 and 1040 Ma from ≥ 600 °C to ~ 200 °C. The zircon (U-Th)/He data from air-abraded grains give a robust isochron age of 1037 ± 25 Ma (2s) without overdispersion. The within-grain homogeneity of U and Th, the availability of FC1 zircon, and the absence of radiation-damage effects on the (U-Th)/He age support its use as reference material. Unabraded zircon grains give lower and more dispersed ages, highlighting the usefulness of air abrasion to control for α-ejection in (U-Th)/He dating. Our apatite (U-Th-Sm)/He single-grain ages vary between 180 and 300 Ma. Their wide dispersion argues against the use of FC1 apatite as (U-Th-Sm)/He reference material and makes the interpretation of their low-temperature thermal history complicated.

中文翻译：

---

德卢斯复合物 FC1 磷灰石和锆石：(U-Th)/He 定年的参考材料？

地质年代和热年代测定的准确性和有效性取决于是否有充分表征的年龄参考材料。明尼苏达州德卢斯杂岩的中元古代辉长斜长岩 FC1 是锆石 U-Pb 的参考材料，也是磷灰石裂变径迹测年的建议参考材料。我们将FC1作为(U-Th)/He参考材料进行评价，并测定其磷灰石U-Pb、锆石和磷灰石(U-Th)/He年龄。我们的测年结果限制了 FC1 的热历史，表明从 ≥ 600 °C 到 ~ 200 °C 的快速冷却发生在约 1099 至 1040 Ma 之间。来自空气磨损颗粒的锆石 (U-Th)/He 数据给出了 1037 ± 25 Ma (2 s），没有过度分散。U 和 Th 的晶粒内均匀性、FC1 ​​锆石的可用性以及 (U-Th)/He 年龄不存在辐射损伤效应，支持其用作参考材料。未磨损的锆石颗粒的年龄更低且更分散，凸显了空气磨损在 (U-Th)/He 测年中控制 α 喷射的有用性。我们的磷灰石 (U-Th-Sm)/He 单晶年龄在 180 到 300 Ma 之间变化。它们的广泛分散性不利于使用 FC1 磷灰石作为 (U-Th-Sm)/He 参考材料，并使对其低温热历史的解释变得复杂。