Mars Reconnaissance Orbiter and Opportunity observations of the Burns formation: Crater hopping at Meridiani Planum
Mars Reconnaissance Orbiter and Opportunity observations of the Burns formation: Crater hopping at Meridiani Planum
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DOI：
10.1002/2014je004686
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发表时间：
2015-03-01
影响因子：
4.8
通讯作者：
Wray, J. J.
中科院分区：
文献类型：
--
作者：
Arvidson, R. E.;Bell, J. F., III;Wray, J. J.
用于火星高光谱（1.0-2.65 μ m）的紧凑型侦察成像光谱仪沿着轨道进行过采样观测，覆盖维多利亚、圣玛丽亚、奋进号和艾达陨石坑，处理到6米/像素，并与机遇号观测结果结合使用，探测和绘制伯恩斯地层中水合硫酸镁和硫酸钙矿物。最强的光谱吸收特征被发现与相对年轻和新鲜的露头（Ada）或优先被盛行风冲刷的灰尘、土壤和涂层有关。在维多利亚和圣玛丽亚，被冲刷的区域位于东南边缘和墙壁上，与风吹沙从火山口延伸出来的两侧相对。在奋进号上，吸收最深的是植物学湾，这是一个隐蔽的边缘部分，表现出高热惯量，广泛的露头，被解释为一个增强的风冲刷区域，向上延伸出陨石坑。艾达、维多利亚和圣玛丽亚的露头暴露了保存完好的伯恩斯地层的上部，并显示了钾辉石存在的光谱证据。相比之下，石膏在植物湾暴露的光谱中是普遍存在的。石膏是一种相对难溶的蒸发矿物，据解释，它是在靠近诺亚亚地壳接触处形成的，因为上升的地下水使盐水接近并进入地表，要么是直接沉淀，要么是在后来的成岩作用中形成的。在这两种情况下，当水环境演变为非常干旱的条件时，假设该剖面顶部的钾辉石的存在反映了蒸发浓缩盐水的降水或多水合硫酸盐的脱水。
Compact Reconnaissance Imaging Spectrometer for Mars hyperspectral (1.0-2.65 mu m) along-track oversampled observations covering Victoria, Santa Maria, Endeavour, and Ada craters were processed to 6m/pixel and used in combination with Opportunity observations to detect and map hydrated Mg and Ca sulfate minerals in the Burns formation. The strongest spectral absorption features were found to be associated with outcrops that are relatively young and fresh (Ada) or preferentially scoured of dust, soil, and coatings by prevailing winds. At Victoria and Santa Maria, the scoured areas are on the southeastern rims and walls, opposite to the sides where wind-blown sands extend out of the craters. At Endeavour, the deepest absorptions are in Botany Bay, a subdued and buried rim segment that exhibits high thermal inertias, extensive outcrops, and is interpreted to be a region of enhanced wind scour extending up and out of the crater. Ada, Victoria, and Santa Maria outcrops expose the upper portion of the preserved Burns formation and show spectral evidence for the presence of kieserite. In contrast, gypsum is pervasive spectrally in the Botany Bay exposures. Gypsum, a relatively insoluble evaporative mineral, is interpreted to have formed close to the contact with the Noachian crust as rising groundwaters brought brines close to and onto the surface, either as a direct precipitate or during later diagenesis. The presence of kieserite at the top of the section is hypothesized to reflect precipitation from evaporatively concentrated brines or dehydration of polyhydrated sulfates, in both scenarios as the aqueous environment evolved to very arid conditions.