A 54 km diameter Noachian-aged crater in the southern highlands of Mars contains unusually well preserved inverted fluvial channel networks and lacustrine deposits, all of which formed completely inside the crater. This “closed-source drainage basin” (CSDB) crater is distinct from previously documented fluvially breached or groundwater-fed crater basin lakes on Mars. We compare our observations to previously established models of crater degradation, fluvial incision, and topographic inversion on Mars to assess the most likely origins of the water that formed the fluvial and lacustrine features. We favor top-down melting of a cold-based glacier as the source of water in the CSDB crater, which would represent the first examples of proglacial fluvial channels and lakes found on Noachian Mars.

在火星南部高地，直径为54公里的Noachian陨石坑包含异常保存完好的倒流河道网络和湖床沉积物，所有这些都完全形成在陨石坑内部。该“闭源流域盆地”（CSDB）火山口与火星上先前记载的河流破裂或由地下水喂养的火山口盆地湖泊不同。我们将我们的观测结果与先前建立的火星上陨石坑退化，河流切口和地形反转的模型进行了比较，以评估形成河流和湖相特征的水的最可能来源。我们赞成将自上而下的冰川融化，作为CSDB火山口中的水源，这将代表Noachian火星上发现的河床河流河道和湖泊的第一个例子。