It is now known unambiguously that wind-driven bedform activity is occurring on the surface of Mars today, including early detections of active sand dunes in Meridiani Planum’s Endeavour crater. Many of these reports are only based on a few sets of observations of relatively isolated bedforms and lack regional context. Here, we investigate aeolian activity across central Meridiani Planum and test the hypothesis that dune sites surrounding Endeavour crater are also active and part of region-wide sediment migration driven by northwesterly winds. All 13 dune fields investigated clearly showed evidence for activity and the majority exhibited dune migration (average rates of 0.6 m/Earth-year). Observations indicate substantial geographic and temporal heterogeneity of dune crest fluxes across the area and per site. Locations with multiple time steps indicate dune sand fluxes can vary by a factor of five, providing evidence for short periods of rapid migration followed by near-stagnation. In contrast, measurements at other sites are nearly identical, indicating that some dunes are in a steady-state as they migrate. The observed sediment transport direction was consistent with a regional northeasterly-to-northwesterly wind regime, revealing more variations than were appreciated from earlier, more localized studies. Craters containing shallow, degraded, flat-floored interiors tended to have dunes with high sediment fluxes/activity, whereas local kilometer-scale topographic obstructions (e.g., central peaks, yardangs) were found to be inversely correlated with dune mobility. Finally, the previous, more limited detections of dune activity in Endeavour crater have been shown to be representative of a broader, region-wide pattern of dune motion.

现在已经明确知道，今天的火星表面正在发生风驱动的地床活动，包括在子午线平原的奋进陨石坑中早期发现的活跃沙丘。其中许多报告仅基于对相对孤立的地貌的几组观察，缺乏区域背景。在这里，我们调查了子午线平原中部的风沙活动，并检验了这样的假设：奋进火山口周围的沙丘地点也很活跃，并且是西北风驱动的区域范围内沉积物迁移的一部分。调查的所有 13 个沙丘场都清楚地显示出活动的证据，并且大多数都表现出沙丘迁移（平均速率为 0.6 m/地球年）。观察表明，整个地区和每个地点的沙丘顶部通量存在显着的地理和时间异质性。具有多个时间步长的位置表明沙丘沙通量可能变化五倍，这为短期快速迁移随后近乎停滞提供了证据。相比之下，其他地点的测量结果几乎相同，这表明一些沙丘在迁移时处于稳定状态。观测到的沉积物输送方向与区域性东北风到西北风态一致，揭示了比早期、更局部的研究所认识到的更多变化。含有浅层、退化、平坦内部的陨石坑往往具有高沉积物通量/活动性的沙丘，而局部公里级地形障碍物（例如，中央山峰、雅丹）被发现与沙丘流动性呈负相关。最后，之前对奋进陨石坑沙丘活动的更有限的检测已被证明代表了更广泛的、全区域的沙丘运动模式。