The European Space Agency and Roscosmos' ExoMars rover mission, which is planned to land in the Oxia Planum region, will be dedicated to exobiology studies at the surface and subsurface of Mars. Oxia Planum is a clay-bearing site that has preserved evidence of long-term interaction with water during the Noachian era. Fe/Mg-rich phyllosilicates have previously been shown to occur extensively throughout the landing area. Here, we analyze data from the High Resolution Imaging Science Experiment (HiRISE) and from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instruments onboard NASA's Mars Reconnaissance Orbiter and the Colour and Stereo Surface Imaging System (CaSSIS) onboard ESA's Trace Gas Orbiter to characterize, at a high spatial resolution, the morphological and spectral variability of Oxia Planum's surface deposits. Two main types of bedrocks are identified within the clay-bearing, fractured unit observed throughout the landing site: (1) an orange type in HiRISE correlated with the strongest detections of secondary minerals (dominated by Fe/Mg-rich clay minerals) with, in some locations, an additional spectral absorption near 2.5 μm, suggesting the mixture with an additional mineral, plausibly carbonate or another type of clay mineral; (2) a more bluish bedrock associated with weaker detections of secondary minerals, which exhibits at certain locations a ∼1 μm broad absorption feature consistent with olivine. Coanalysis of the same terrains with the recently acquired CaSSIS images confirms the variability in the color and spectral properties of the fractured unit. Of interest for the ExoMars mission, both types of bedrocks are extensively outcropping in the Oxia Planum region, and the one corresponding to the most intense spectral signals of clay minerals (the primary scientific target) is well exposed within the landing area, including near its center.

中文翻译：

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ExoMars 着陆点 Oxia Planum 含粘土单元的形态和光谱多样性

欧洲航天局和 Roscosmos 的 ExoMars 漫游车任务计划降落在 Oxia Planum 地区，将致力于火星表面和地下的外生生物学研究。Oxia Planum 是一个含粘土的遗址，保留了诺亚时代与水长期相互作用的证据。先前已证明富含铁/镁的页硅酸盐在整个着陆区广泛存在。在这里，我们分析了来自高分辨率成像科学实验 (HiRISE) 和来自美国宇航局火星侦察轨道器上的紧凑型火星侦察成像光谱仪 (CRISM) 以及欧空局微量气体轨道器上的彩色和立体表面成像系统 (CaSSIS) 的数据，以以高空间分辨率表征 Oxia Planum 的形态和光谱变异性 s 表面沉积物。在整个着陆点观察到的含粘土的断裂单元内确定了两种主要类型的基岩：（1）HiRISE 中的橙色类型与次生矿物（以富含铁/镁的粘土矿物为主）的最强检测相关，在某些位置，额外的光谱吸收接近 2.5 μm，表明与其他矿物（可能是碳酸盐或其他类型的粘土矿物）的混合物；(2) 更蓝的基岩与较弱的次生矿物检测相关，在某些位置表现出与橄榄石一致的~1μm 宽吸收特征。对相同地形与最近获得的 CaSSIS 图像进行的共同分析证实了破裂单元的颜色和光谱特性的可变性。对 ExoMars 任务感兴趣，