Sedimentary amorphous and nanocrystalline materials are abundant on Mars, but their formation conditions are poorly understood due in part to instrument limitations and the lack of knowledge about terrestrial sedimentary amorphous and nanocrystalline material compositions and structures. Additionally, it is surprising that the Curiosity rover finds these metastable phases preserved in ancient (3‐4 Gya) rocks in Gale crater. Here, we use X‐ray diffraction and high resolution transmission electron microscopy (HRTEM) to investigate the X‐ray amorphous weathering products found in soils, sediments, and paleosols from Mars‐relevant mafic to intermediate volcanic terrains altered under different climates. The X‐ray amorphous components of our samples are often complex mixtures of amorphous and nanocrystalline materials with compositions that vary at the nanometer‐scale, but are dominated by iron‐oxide, Al₂O₃, and SiO₂, the proportions of which reflect large‐scale weathering conditions, such that those formed in warm and wet climates are deficient in more mobile cations, and those formed under cooler climates reflect restricted cation leaching. We also find high abundances (∼40 wt.%) of X‐ray amorphous weathering products in lithified and diagenetically altered volcanic soils that have been preserved over timescales of ∼10⁷ years. These results have wide‐reaching implications for soil property and paleoclimate investigations on Earth and Mars, and suggest that amorphous and nanocrystalline materials are important, but overlooked components of some sedimentary rocks on Earth. Future investigations are needed to better understand the kinetics behind the transformation from amorphous and nanocrystalline to crystalline materials and the factors that allow their preservation on Earth and Mars.

中文翻译：

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从地球上的镁铁矿到中火山的天然无定形和纳米晶体风化产物的纳米尺度变化：对火星上无定形探测的意义

沉积的非晶态和纳米晶材料在火星上非常丰富，但是由于仪器的局限性以及对陆地沉积非晶态和纳米晶材料的组成和结构的了解不足，人们对它们的形成条件了解甚少。此外，令人惊讶的是，好奇心流动站发现这些亚稳相保留在大风火山口的古代（3-4 Gya）岩石中。在这里，我们使用X射线衍射和高分辨率透射电子显微镜（HRTEM）来研究在不同气候条件下从火星相关的黑手党到中层火山地形的土壤，沉积物和古土壤中发现的X射线无定形风化产物。我们样品的X射线无定形成分通常是无定形和纳米晶材料的复杂混合物，其组成在纳米级上有所不同，但主要由氧化铁，Al ₂ O ₃和SiO _2组成。，其比例反映了大规模的风化条件，例如在温暖和潮湿的气候条件下形成的比例缺乏更多的可移动阳离子，而在较凉爽的气候条件下形成的比例则反映了有限的阳离子浸出。我们还发现，在大约^{10 7}时间范围内保存的，由石化和双磁化蚀变的火山土壤中，X射线无定形风化产物的含量很高（约40 wt。％）。年。这些结果对土壤性质和地球和火星的古气候研究具有深远的意义，并表明无定形和纳米晶体材料是重要的，但却忽略了地球上某些沉积岩的组成部分。需要进行进一步的研究，以更好地理解从无定形和纳米晶体到晶体材料的转变背后的动力学，以及使其在地球和火星上得以保存的因素。