Wrinkle ridges are the predominant tectonic structure on the nearside lunar maria. Although lunar wrinkle ridge formation began as early as ∼3.9–4.0 Ga, recent investigations have identified wrinkle ridges in the lunar maria that were tectonically active as recently as the Copernican period of lunar geologic history. Some of those geologically young wrinkle ridges were identified by the presence of dense fields of meter-scale boulders on their scarps and topographic crests. Other investigations have identified recently active lunar wrinkle ridges that lack the ubiquitous presence of boulder fields, thereby rendering the presence of boulder fields ambiguous in the search for ongoing tectonic activity on the Moon. Here we assess boulder populations associated with 1116 wrinkle ridge segments on the lunar maria that are inferred to be recently active (<1.5 Ga) based on their crisp morphologies and crosscutting relationships with small impact craters. We utilize data from the Lunar Reconnaissance Orbiter Mini-RF and Diviner Lunar Radiometer Experiment instruments to assess surface rock populations across these recently active structures. Our results indicate that, where present, meter-scale boulder fields are likely indicators of fault-slip-induced ground acceleration given the short lifespan of lunar surface boulders. However, elevated boulder populations are not observed on all recently active ridges analyzed here. This latter observation supports the notion that wrinkle ridge boulder fields are a nonunique indicator of recent tectonic activity. Furthermore, the spatial distribution of those boulder fields indicates that variable mare protolith properties may play a role in boulder field formation.

中文翻译：

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月球巨石场作为近期构造活动的指标

皱纹脊是月海近侧的主要构造结构。尽管月球皱纹脊的形成早在∼3.9–4.0 Ga时就开始了，但最近的研究发现月海中的皱纹脊早在月球地质历史的哥白尼时期就处于构造活动状态。其中一些地质上年轻的皱纹山脊是通过其陡坡和地形顶部密集的米级巨石区域来识别的。其他研究发现，最近活跃的月球皱纹山脊缺乏无处不在的巨石场，因此在寻找月球上正在进行的构造活动时，巨石场的存在变得模糊不清。在这里，我们评估了与月海 1116 个皱纹脊段相关的巨石群，根据其清晰的形态和与小型撞击坑的横切关系，推断这些巨石最近处于活动状态（<1.5 Ga）。我们利用月球勘测轨道器迷你射频和占卜者月球辐射计实验仪器的数据来评估这些最近活跃的结构的表面岩石数量。我们的结果表明，鉴于月球表面巨石的寿命较短，米级巨石场可能是断层滑动引起的地面加速度的指标。然而，在此处分析的所有最近活跃的山脊上并未观察到巨石数量增加。后一个观察结果支持这样的观点，即皱纹山脊巨石场是近期构造活动的非唯一指标。此外，这些巨石场的空间分布表明，可变的海海原岩特性可能在巨石场的形成中发挥作用。