Visible/short‐wave infrared spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show absorptions attributed to hematite at Vera Rubin ridge (VRR), a topographic feature on northwest Mt. Sharp. The goals of this study are to determine why absorptions caused by ferric iron are strongly visible from orbit at VRR and to improve interpretation of CRISM data throughout lower Mt. Sharp. These goals are achieved by analyzing coordinated CRISM and in situ spectral data along the Curiosity Mars rover's traverse. VRR bedrock within areas that have the deepest ferric absorptions in CRISM data also has the deepest ferric absorptions measured in situ. This suggests strong ferric absorptions are visible from orbit at VRR because of the unique spectral properties of VRR bedrock. Dust and mixing with basaltic sand additionally inhibit the ability to measure ferric absorptions in bedrock stratigraphically below VRR from orbit. There are two implications of these findings: (1) Ferric absorptions in CRISM data initially dismissed as noise could be real, and ferric phases are more widespread in lower Mt. Sharp than previously reported. (2) Patches with the deepest ferric absorptions in CRISM data are, like VRR, reflective of deeper absorptions in the bedrock. One model to explain this spectral variability is late‐stage diagenetic fluids that changed the grain size of ferric phases, deepening absorptions. Curiosity's experience highlights the strengths of using CRISM data for spectral absorptions and associated mineral detections and the caveats in using these data for geologic interpretations and strategic path planning tools.

中文翻译：

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夏普山和维拉鲁宾山脊上氧化铁的协同地面和轨道观测


来自火星紧凑侦察成像光谱仪 (CRISM) 的可见光/短波红外光谱数据显示，维拉鲁宾山脊 (VRR) 的赤铁矿吸收，这是夏普山西北部的一个地形特征。这项研究的目的是确定为什么三价铁引起的吸收在 VRR 轨道上清晰可见，并改进对整个夏普山下部 CRISM 数据的解释。这些目标是通过分析协调的 CRISM 和好奇号火星探测器沿线的原位光谱数据来实现的。 CRISM 数据中铁吸收最深区域内的 VRR 基岩也具有原位测量的最深铁吸收。这表明由于 VRR 基岩独特的光谱特性，从 VRR 轨道上可以看到强烈的铁吸收。灰尘以及与玄武岩砂的混合还会抑制从轨道测量 VRR 以下基岩地层中铁吸收的能力。这些发现有两个含义：(1) CRISM 数据中的三价铁吸收最初被忽略，因为噪声可能是真实的，并且三价铁相在夏普山下部比以前报道的更广泛。 (2) CRISM 数据中铁吸收最深的斑块（如 VRR）反映了基岩中更深的吸收。解释这种光谱变化的一个模型是晚期成岩流体，它改变了铁相的晶粒尺寸，加深了吸收。好奇号的经验凸显了使用 CRISM 数据进行光谱吸收和相关矿物检测的优势，以及使用这些数据进行地质解释和战略路径规划工具的注意事项。