月陆地区次级撞击坑特征及年龄统计方法

通过撞击坑的大小频率计算月表的地质年龄是一种行之有效的方法，包括累积分布法和相对分布法。其中累计分布法在已知撞击坑直径范围的基础上，可分为3种年代函数计算月表的地层单元，分别是Melosh 和 Vickery 1989 (直径大于4 km 撞击坑), Neukum 1983(直径大于1 km撞击坑)和李坤等2012(直径小于1 km 撞击坑)。应用高分辨率影像SELENE TC(10m/pixel)数据，完成了Apollo 14及Apollo 16登月区域地层单元的解译，并应用撞击坑直径频率统计方法获取同一地层单元的形成年龄。通过与Apollo登月区域样品同位素年龄对照，得出Neukum 1983(直径大于1 km撞击坑)相对于其他几种方法更加准确，同时分析了撞击坑的退化、次级撞击坑影响等相关问题。

Crater sizefrequency distribution measurements and the secondary craters features of lunar high lands

Crater sizefrequency distribution is a powerful method for estimating the age of a planet’s surface, including the cumulative sizefrequency distribution method and the relative sizefrequency distribution one. According to the diameter range of craters, three chronology functional expressions are available for calculating the geologic age of stratigraphic units, including Melosh and Vickery 1989 (＞4 km craters), Neukum 1983(＞1 km craters), and LI Kun et al 2012(＜1 km craters). The SELENE TC data are used to interpret the Apollo 14 and Apollo 16 landing sites areas owing to their high spatial resolution (10 m/pixel). Thus, a crater numbering criteria and new chronology functional expressions are built by the real isotope ages surrounding Apollo 14 and Apollo 16 landing sites areas. By comparison, it shows that the algorithm with larger than 1 km craters by Neukum 1983, performs better than the others. The influences of age uncertainty, degradation and secondary impact craters have been analyzed.