In the aeolian-dominated conditions of modern Mars, wind-driven sediment deposition and erosion produce a wide range of enigmatic landforms on the planet's surface. In this work, we explore a widespread occurrence of paleodunes on the surface of Mars. These fossilized bedforms preserve morphologies consistent with transverse dunes, implying an approximately unimodal ancient sediment transport azimuth and abundant sediment supply. These bedforms have previously been interpreted as layered dust deposits, and their bland, dust-like reflectance spectra are consistent with volcanic ash. Additionally, these paleodunes have undergone induration and have been significantly eroded by recent winds, causing a superimposed yardang-like erosional texture on the older dune morphology. We propose that these unusual bedforms most likely occurred as wind-mobilized pyroclastics that welded or were cemented in place after deposition and have since eroded into a field of hybrid paleobedform/proto-yardangs.

在现代火星的风沙主导条件下，风驱动的沉积物沉积和侵蚀在行星表面产生了各种各样的神秘地貌。在这项工作中，我们探索了火星表面古生物的广泛存在。这些化石床形保留了与横向沙丘相一致的形态，这意味着大约单峰的古代沉积物输送方位和丰富的沉积物供应。这些床形以前曾被解释为分层的粉尘沉积物，其平淡的粉尘状反射光谱与火山灰一致。此外，这些古龟已经硬化，并受到新近风的侵蚀，从而在较早的沙丘形态上形成了像堆场一样的侵蚀性侵蚀纹理。