近日，美国加州理工学院Abdallah S. Zaki团队报道了识别早期火星海洋的地形特征。相关论文于2026年4月15日发表在《自然》杂志上。

对火星上海岸线的全球性解读表明，火星曾拥有一个覆盖其表面三分之一的早期海洋。然而，这些海岸线的高程偏离等势面达数公里，这对此解读提出了挑战。

研究组探究一个曾经拥有海洋的行星是否应留下可识别的海岸线。他们表明，在地球上，全球性海洋最显著的地形特征并非海岸线，而是一个由海岸平原和大陆架组成的低坡度、低曲率值带状区域，其高程范围为-410米至-15米。将类似的分析应用于火星表面时，研究组观察到一个高程约在-1,800米至-3,800米之间的相对平坦带，这可能代表了一个部分保存下来的火星海岸架。

尽管其他过程（如熔岩流）可以解释局部的平坦区域，但海岸架能够最佳地解释环绕全球的平坦地形带，此外，在假定的海岸架区域内还观测到了河流三角洲沉积、海岸沉积、厚层状岩石序列以及水蚀变矿物。该研究结果支持火星上存在古代海洋，并表明地形架可能比海岸线更能指示长期存在的海洋。

附：英文原文

Title: Identifying the topographic signature of early Martian oceans

Author: Zaki, Abdallah S., Lamb, Michael P.

Issue&Volume: 2026-04-15

Abstract: Planet-wide interpretations of shorelines suggest that Mars once hosted an early ocean covering one-third of its surface1,2,3,4,5,6,7,8,9. However, the elevations of these shorelines deviate from an equipotential surface by several kilometres, challenging that interpretation3,7,10,11,12. Here we investigate whether a planet that once hosted an ocean should be expected to leave discernible shorelines. We show that on Earth, the most prominent topographic signature of a global ocean is not a shoreline. Rather, it is a band of low slope and curvature values that comprises coastal plains and the continental shelf, with an elevation range of 410m to 15m. When applying a similar analysis to the Martian surface, we observe a comparably flat zone between approximately –1,800m and –3,800m elevation, potentially marking a partially preserved Martian coastal shelf. Although other processes, such as lava flows13, might explain flat regions locally, a coastal shelf best explains the circumglobal band of flat topography, in addition to river delta deposits4,14,15,16,17, coastal deposits18, thick sequences of layered rock19,20 and aqueously altered minerals20,21, all observed within the putative coastal shelf zone. Our results support the presence of an ancient ocean on Mars and indicate that topographic shelves rather than shorelines may be better indicators of long-lived oceans.

DOI: 10.1038/s41586-026-10381-2

Source: https://www.nature.com/articles/s41586-026-10381-2