锆石U-Pb定年与微量元素分析的地质应用

 锆石U-Pb定年与微量元素同时测定的原位微区分析是目前应用最广泛的地质测年方法之一，对锆石形貌学、内部结构及地球化学特征进行深入研究，是正确理解、解释锆石原位微区分析测年结果的关键。通过锆石的阴极发光图像（CL）、背散射电子图像（BSE），结合锆石的Th/U比值及稀土配分模式曲线特征，可判别不同锆石的成因类型；通过锆石的微量元素分析，可判别锆石寄主岩石的成因类型及形成环境；利用Ti温度计可限定岩体的岩浆源区深度范围，结合锆石寄主岩石类型及寄主岩石中深源包裹体的研究，可进一步推断锆石母岩浆的起源。锆石U-Pb定年与微量元素分析相结合的地质测年方法，已成功地应用于最大沉积地层时代限定、碎屑岩物源分析以及古洋盆演化过程约束等方面，且具有强有力的发展前景。

Zircon U-Pb dating and its trace element analysis applied to geology

Zircon U-Pb dating and trace elements in situ microanalysis is one of the most widely used methods of geological dating. The zircon morphology, internal structure and geochemistry significance in-depth study are the key to properly understanding and interpreting the meaning of in situ microanalysis zircon dating. By zircon cathodoluminescence, backscattered electron images, combined with zircon Th/U ratios and the characteristic of REE distribution patterns, we can determine different types of zircon. Zircon trace elements can reflect genetic types and environment of host rocks. Zircon Ti thermometer may limit the depth of the magma source rock range. Combining zircon host rock types and the study of deep source inclusion in host rocks may further reflect the parent magma origin. Combination of zircon UPb dating and trace elements is an important method that has been successfully applied to determining maximum depositional age, provenance analysis, closure time of the paleo-ocean and so on. There is a strong development prospect for it.