Submarine cyclic steps have a significant impact on the evolution of the ocean floor on Earth. These upper-flow regime bedforms should be even more common in Martian reduced-gravity environments. We postulate that, if early Mars had an ocean, cyclic steps would have formed on Martian deltas spreading along the putative ancient shorelines in the northern plains. The main challenge to identifying submarine cyclic steps on Mars is geologic activity, in particular impacts, volcanism, and aeolian erosion, which have erased or modify much of the geomorphic evidence. Even though many Martian deltaic deposits do not bear much resemblance to the original depositional surfaces, we hypothesize that cementation and consolidation of marine sediments had facilitated the preservation of at least some Martian cyclic steps on deltaic deposits. We combine data from several orbital missions at Mars with a literature review and numerical analysis to inspect bedforms near the foreset-bottomset transition of 17 documented deltaic deposits. The most promising piece of evidence for Martian submarine cyclic steps is a linear series of rhythmic long-wavelength bedforms within a channel incised into the upper delta front of the Aeolis Mensae Delta. These bedforms are remarkably similar to their counterparts observed in channels on deltas and deep-water fans on Earth. Moreover, we speculate that two fields of cyclic steps, likely emanating from a crater upstream of the Aeolis Mensae Delta, are a potential example of contemporary cyclic steps and attest to the sporadic presence of flowing water on present-day Mars.

中文翻译：

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火星上的水：红色星球上是否存在海底循环步骤？

海底循环步骤对地球海底的演变有重大影响。这些高流态床形在火星重力降低的环境中应该更为常见。我们假设，如果早期的火星有海洋，则将在北部平原假定的古老海岸线上扩散的火星三角洲上形成周期性的台阶。识别火星上海底循环步骤的主要挑战是地质活动，尤其是撞击，火山活动和风蚀，这些活动已经抹去或修饰了许多地貌证据。即使许多火星三角洲沉积物与原始沉积面没有太大相似之处，我们仍认为海洋沉积物的胶结和固结已经促进了三角洲沉积物中至少一些火星循环步骤的保存。我们将来自火星的几个轨道飞行任务的数据与文献综述和数值分析相结合，以检查17个有记录的三角洲沉积的前底部向底部过渡附近的地层。火星海底循环步骤最有前途的证据是在切入风神三角洲上三角洲前缘的河道内的一系列有节奏的长波床形。这些床形与在三角洲和地球上深水扇形通道中观察到的床形极为相似。此外，我们推测，可能来自风神Mensae三角洲上游火山口的两个循环阶梯场是当代循环阶梯的潜在例子，并证明了当今火星上零星存在流动的水。火星海底循环步骤最有前途的证据是在切入风神三角洲上三角洲前缘的河道内的一系列有节奏的长波床形。这些床形与在三角洲和地球上深水扇形通道中观察到的床形极为相似。此外，我们推测，可能来自风神Mensae三角洲上游火山口的两个循环阶梯场是当代循环阶梯的潜在例子，并证明了当今火星上零星存在流动的水。火星海底循环步骤最有前途的证据是在切入风神三角洲上三角洲前缘的河道内的一系列有节奏的长波床形。这些床形与在三角洲和地球上深水扇形通道中观察到的床形极为相似。此外，我们推测，可能来自风神Mensae三角洲上游火山口的两个循环阶梯场是当代循环阶梯的潜在例子，并证明了当今火星上零星存在流动的水。这些床形与在三角洲和地球上深水扇形通道中观察到的床形极为相似。此外，我们推测，可能来自风神Mensae三角洲上游火山口的两个循环阶梯场是当代循环阶梯的潜在例子，并证明了当今火星上零星存在流动的水。这些床形与在三角洲和地球上深水扇形通道中观察到的床形极为相似。此外，我们推测，可能来自风神Mensae三角洲上游火山口的两个循环阶梯场是当代循环阶梯的潜在例子，并证明了当今火星上零星存在流动的水。