Lunar Mare Soils: Space weathering and the major effects of surface‐correlated nanophase Fe

Taylor, L. A.; Pieters, C. M.; Keller, L. P.; Morris, R. V.; McKay, D. S.

doi:10.1029/2000je001402

Cited by 297 publications

(284 citation statements)

References 20 publications

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“…Qualitatively, our pyroxene map is also similar to the sum of low-Ca pyroxene and clinopyroxene derived by (Lemelin et al, 2016), but the summed pyroxene fractions of (Lemelin et al, 2016) in the nearside maria correspond to 60% and more. In contrast, the laboratory analyses of (Taylor et al, 2001) of lunar mare samples have shown that the total pyroxene content of these samples is always less than 34% and in many cases below 20%.…”

Section: Resultsmentioning

confidence: 98%

“…Only the 20-45 µm grain size fraction was taken into account. This data set is well suited for spectral unmixing on large scales because it consists of soil sample spectra exhibiting similar spaceweathering effects as remotely sensed spectra of the lunar soil (Taylor et al, 2001).…”

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

“…The obtained endmember fractions were normalized to a sum of 1. The LSCC compositional laboratory analyses state the modal abundances of a variety of mineral species for all 19 samples used as spectral endmembers (Taylor et al, 2001, Taylor et al, 2010. These data allow for a conversion from endmember fractions into mineral fractions.…”

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

“…To each of the 64 cluster prototype spectra the MPBIL-based spectral unmixing algorithm with a population size of npop = 20 was applied, yielding 64 cluster-specific sets of endmembers. As a catalogue of potential endmembers for spectral unmixing, the set of 19 laboratory spectra of lunar mare and highland samples provided by the Lunar Soil Characterization Consortium (LSCC) (Taylor et al, 2001, Taylor et al, 2010 was used. Only the 20-45 µm grain size fraction was taken into account.…”

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

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Spectral Unmixing Based Construction of Lunar Mineral Abundance Maps

Bernhardt

Grumpe

Wöhler

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:In this study we apply a nonlinear spectral unmixing algorithm to a nearly global lunar spectral reflectance mosaic derived from hyperspectral image data acquired by the Moon Mineralogy Mapper (M 3 ) instrument. Corrections for topographic effects and for thermal emission were performed. A set of 19 laboratory-based reflectance spectra of lunar samples published by the Lunar Soil Characterization Consortium (LSCC) were used as a catalog of potential endmember spectra. For a given spectrum, the multi-population population-based incremental learning (MPBIL) algorithm was used to determine the subset of endmembers actually contained in it. However, as the MPBIL algorithm is computationally expensive, it cannot be applied to all pixels of the reflectance mosaic. Hence, the reflectance mosaic was clustered into a set of 64 prototype spectra, and the MPBIL algorithm was applied to each prototype spectrum. Each pixel of the mosaic was assigned to the most similar prototype, and the set of endmembers previously determined for that prototype was used for pixel-wise nonlinear spectral unmixing using the Hapke model, implemented as linear unmixing of the singlescattering albedo spectrum. This procedure yields maps of the fractional abundances of the 19 endmembers. Based on the known modal abundances of a variety of mineral species in the LSCC samples, a conversion from endmember abundances to mineral abundances was performed. We present maps of the fractional abundances of plagioclase, pyroxene and olivine and compare our results with previously published lunar mineral abundance maps.

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Section: Resultsmentioning

confidence: 98%

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

Section: Construction Of Nearly Global Lunar Mineral Abundance Mapsmentioning

confidence: 99%

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Spectral Unmixing Based Construction of Lunar Mineral Abundance Maps

Bernhardt

Grumpe

Wöhler

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…However, it remained for Pieters et al (27,28) to characterize the effects of the np-Fe 0 , especially in the smallest-size fraction, on the optical properties of lunar soil. The results of the Lunar Soil Characterization Consortium, a group of lunar scientists concentrating on the physical and chemical properties of lunar soils, have provided considerable data that relate the calibration of the spectra of the soils to the ground truth of what is actually in the soils for application to the methods of remote compositional analysis (24,28,29).…”

Section: Formation Of Nano-phase Metallic Fementioning

confidence: 99%

Space weathering on airless planetary bodies: Clues from the lunar mineral hapkeite

Anand

Taylor

Назаров

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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119

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Physical and chemical reactions occurring as a result of the highvelocity impacts of meteorites and micrometeorites and of cosmic rays and solar-wind particles are major causes of space weathering on airless planetary bodies, such as the Moon, Mercury, and asteroids. These weathering processes are responsible for the formation of their regolith and soil. We report here the natural occurrence of the mineral hapkeite, a Fe 2Si phase, and other associated Fe-Si phases (iron-silicides) in a regolith breccia clast of a lunar highland meteorite. These Fe-Si phases are considered to be a direct product of impact-induced, vapor-phase deposition in the lunar soil, all part of space weathering. We have used an in situ synchrotron energy-dispersive, single-crystal x-ray diffraction technique to confirm the crystal structure of hapkeite as similar to the structure of synthetic Fe 2Si. This mineral, hapkeite, is named after Bruce Hapke of the University of Pittsburgh, who predicted the presence and importance of vapor-deposited coatings on lunar soil grains some 30 years ago. We propose that this mineral and other Fe-Si phases are probably more common in the lunar regolith than previously thought and are directly related to the formation of vapor-deposited, nanophase elemental iron in the lunar soils.

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Characterization of space weathering from Lunar Reconnaissance Orbiter Camera ultraviolet observations of the Moon

Denevi

Robinson

Boyd

et al. 2014

J. Geophys. Res. Planets

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We investigate the effects of space weathering at ultraviolet wavelengths using a near-global seven-band (321-689 nm) mosaic from the Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC). We confirm that for moderate-to high-iron compositions (≳ 5 wt % FeO), the steeply positive UV slope at wavelengths <415 nm shallows with increasing exposure to space weathering. We measure these differences in LROC WAC data as variations in the 321/415 nm ratio, which has low values for fresh craters in the mare and moderate-iron highlands. For low-iron highland compositions, the break in slope occurs at shorter wavelengths, and it is instead the 321/360 nm ratio that increases with exposure to the space-weathering environment, whereas the 321/415 nm ratio appears to be largely controlled by the degree of shock experienced during the impact. The effects of shock may be more important at highland craters because modest shock pressures result in the solid-state transformation of plagioclase to its glass equivalent, maskelynite, and can help distinguish between primary shocked ejecta and locally exposed fresh material in rays. While all of the "fresh" craters we examined have UV spectral properties consistent with substantial alteration due to space weathering, the UV spectra of lunar swirls (magnetically shielded from the solar wind) are consistent with exposure of immature, crystalline material. Together these results suggest that lunar space weathering is dominated by the solar wind and "saturates" in the UV at I s /FeO values of 40 (submature).

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Lunar Mare Soils: Space weathering and the major effects of surface‐correlated nanophase Fe

Cited by 297 publications

References 20 publications

Spectral Unmixing Based Construction of Lunar Mineral Abundance Maps

Spectral Unmixing Based Construction of Lunar Mineral Abundance Maps

Space weathering on airless planetary bodies: Clues from the lunar mineral hapkeite

Characterization of space weathering from Lunar Reconnaissance Orbiter Camera ultraviolet observations of the Moon

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