DOI: 10.1029/2018JE005553
Scopus记录号: 2-s2.0-85050491521
论文题名: Dusty Rocks in Gale Crater: Assessing Areal Coverage and Separating Dust and Rock Contributions in APXS Analyses
作者: Schmidt M.E. ; Perrett G.M. ; Bray S.L. ; Bradley N.J. ; Lee R.E. ; Berger J.A. ; Campbell J.L. ; Ly C. ; Squyres S.W. ; Tesselaar D.
刊名: Journal of Geophysical Research: Planets
ISSN: 21699097
出版年: 2018
卷: 123, 期: 7 起始页码: 1649
结束页码: 1673
语种: 英语
英文关键词: Alpha Particle X-ray Spectrometer
; Mars dust
; Mars Hand Lens Imager
; Mars Science Laboratory
; Mars surface geochemistry
英文摘要: A thin, patchy layer of airfall dust covers rock surfaces examined by the Mars Science Lab rover Curiosity and complicates interpretation of textures in Mars Hand Lens Imager images and compositions determined by Alpha Particle X-ray Spectrometer (APXS). Using three image processing methods, we estimate dust coverages for Mars Hand Lens Imager images of APXS targets to Sol 1512. Dust coverages of as is rock targets range from 6% to 77% (±5% to 10% estimated error). Targets brushed by the Dust Removal Tool range to lower coverages than as is targets, but quality depends on surface type; brushed mudstones have the narrowest range and lowest coverages (11–25%), while sandstones vary, ranging to higher coverages (12–58%). Groups of rocks with similar compositions (APXS classes) can have strong correlations between dust coverage and SO3/Cl (up to r = 0.985). Dust can also strongly affect the lightest elements measured (Na to Ca). By comparing paired as is and Dust Removal Tool analyses, using the determined dust coverages, and finding a best fit dust thickness (generally ~10 μm), we model relative contributions of the dust and bedrock to extrapolate dust-free compositions for homogeneous APXS classes. The dust is basaltic with high S and Cl. Dust-free rocks have higher SiO2 and Na2O (up to 6.5 wt% and 0.5 wt% higher, respectively) and lower SO3 and CaO (up to 5.5 wt% and 1.3 wt% lower, respectively) than dusty equivalents. Dust most influences compositions that are very different from average Mars, including the alkali-rich, MgO-poor Jake M class. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113586
Appears in Collections: 气候减缓与适应
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作者单位: Department of Earth Sciences, Brock University, St. Catharines, ON, Canada; Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY, United States; Now at Department of Physics and Computer Science, Now at Wilfrid Laurier University, Waterloo, ON, Canada; Now at Lafarge Aggregates, Mississauga, ON, Canada; Department of Physics, University of Guelph, Guelph, ON, Canada
Recommended Citation:
Schmidt M.E.,Perrett G.M.,Bray S.L.,et al. Dusty Rocks in Gale Crater: Assessing Areal Coverage and Separating Dust and Rock Contributions in APXS Analyses[J]. Journal of Geophysical Research: Planets,2018-01-01,123(7)