Abstract As a semi-enclosed crater basin on the northwest rim of Imbrium basin, Sinus Iridum is a key site to investigate the geological characteristics at the intersection of two basins. For this reason, we focused on model age determination in Sinus Iridum basin using Chang’E−2 high-resolution images coupled with compositional maps from the Clementine data sets, as well as with digital elevation models (DEMs) from the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO). With these datasets we identified different geologic units onto which we performed model age determinations based on crater counting. This systematic analysis of the Sinus Iridum basin shows that the age of the oldest exposed basaltic unit is 3.37 ​Ga (Imbrian age), while the youngest, a mare basalt unit that enters the basin from Imbrium basin, is 1.24 ​Ga (late Eratosthenian). In general, the ages of the geologic units inside the Sinus Iridum basin gradually decrease from the northeast to the southwest, with the only exception of the young units being located in the north-eastern area. We conclude that the crater size-frequency distributions (CSFD) reflect a multi-layer sequence, suggesting multiple resurfacing events inside Sinus Iridum. The model age determinations identify several infilling events of basalts ranging from 3.37 ​Ga to 1.24 ​Ga, which are all derived mare basalt flows from the Imbrium basin.

中文翻译：

---

虹鳟盆地的地质演化

摘要 作为雨海盆地西北缘的半封闭火山口盆地，铱星盆地是研究两盆地交汇处地质特征的重点地点。出于这个原因，我们专注于使用嫦娥-2 高分辨率图像加上来自 Clementine 数据集的成分图以及来自月球轨道器激光高度计的数字高程模型 (DEM) 来确定 Sinus Iridum 盆地的模型年龄(LOLA) 在月球勘测轨道飞行器 (LRO) 上。通过这些数据集，我们确定了不同的地质单元，我们根据陨石坑计数对其进行了模型年龄确定。对虹湾盆地的系统分析表明，最古老的出露玄武岩单元的年龄为 3.37 Ga（雨海纪），而最年轻的玄武岩单元是从雨海盆地进入盆地的，是 1.24 Ga（埃拉托斯特晚期）。总的来说，虹湾盆地内地质单元年龄从东北向西南逐渐递减，只有年轻单元位于东北地区。我们得出结论，陨石坑大小频率分布 (CSFD) 反映了一个多层序列，表明 Sinus Iridum 内部发生了多次重铺事件。模型年龄确定确定了从 3.37 Ga 到 1.24 Ga 的几个玄武岩充填事件，它们都是来自雨海盆地的玄武岩流。我们得出结论，陨石坑大小频率分布 (CSFD) 反映了一个多层序列，表明 Sinus Iridum 内部发生了多次重铺事件。模型年龄确定确定了从 3.37 Ga 到 1.24 Ga 的几个玄武岩充填事件，它们都是来自雨海盆地的玄武岩流。我们得出结论，陨石坑大小频率分布 (CSFD) 反映了一个多层序列，表明 Sinus Iridum 内部发生了多次重铺事件。模型年龄确定确定了从 3.37 Ga 到 1.24 Ga 的几个玄武岩充填事件，它们都是来自雨海盆地的玄武岩流。