Mineralogy of volcanic rocks in Gusev Crater, Mars: Reconciling Mössbauer, Alpha Particle X‐Ray Spectrometer, and Miniature Thermal Emission Spectrometer spectra
Mineralogy of volcanic rocks in Gusev Crater, Mars: Reconciling Mössbauer, Alpha Particle X‐Ray Spectrometer, and Miniature Thermal Emission Spectrometer spectra
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火星古谢夫陨石坑火山岩的矿物学：调和穆斯堡尔谱、阿尔法粒子 X 射线光谱仪和微型热发射光谱仪光谱
DOI：
10.1029/2007je002970
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发表时间：
2008
影响因子：
--
通讯作者：
A. Yen
中科院分区：
文献类型：
--
作者：
H. McSween;S. Ruff;R. Morris;R. Gellert;G. Klingelhöfer;P. Christensen;T. Mccoy;A. Ghosh;J. Moersch;B. Cohen;A. D. Rogers;C. Schröder;S. Squyres;J. Crisp;A. Yen
[1] 通过将穆斯堡尔子光谱面积建模为矿物重量百分比，并将这些百分比与穆斯堡尔未检测到的无铁矿物（根据阿尔法粒子X射线光谱仪（APXS）化学分析计算出的标准斜长石、磷灰石和铬铁矿）的比例相结合，确定了古谢夫陨石坑中相对未蚀变的火山岩或火山碎屑岩的完整矿物丰度集合。针对这些矿物模式计算出的合成热发射光谱与同一岩石类别测量的微型热发射光谱仪（Mini - TES）光谱进行比较，结果要么高度吻合，要么存在差异，我们将这些差异归因于钠质斜长石成分或未建模的硫酸盐、玻璃或易变辉石。根据APXS数据计算出的橄榄石、辉石和长石的标准成分与矿物成分的光谱限制一致。APXS标准中的橄榄石丰度（取样深度为数十微米）与穆斯堡尔测量的橄榄石比例（取样深度为数百微米）之间的系统性变化支持了在风化岩石表面发生了酸性流体溶解橄榄石这一假设。
[1] Complete sets of mineral abundances for relatively unaltered volcanic or volcaniclastic rocks in Gusev Crater have been determined by modeling Mossbauer subspectral areas as mineral weight percentages, and combining those percentages with the proportions of iron-free minerals not detected by Mossbauer (normative plagioclase, apatite, and chromite, as calculated from Alpha Particle X-Ray Spectrometer (APXS) chemical analyses). Comparisons of synthetic thermal emission spectra calculated for these mineral modes with measured Miniature Thermal Emission Spectrometer (Mini-TES) spectra for the same rock classes show either good agreements or discrepancies that we attribute to sodic plagioclase compositions or unmodeled sulfate, glass, or pigeonite. The normative compositions of olivine, pyroxene, and feldspar calculated from APXS data are consistent with spectroscopic constraints on mineral compositions. Systematic variations between olivine abundances in APXS norms (which sample tens of micrometers depth) and olivine proportions measured by Mossbauer (which sample hundreds of micrometers depth) support the hypothesis that dissolution of olivine by acidic fluids has occurred on weathered rock surfaces.