Spectral mineralogy of terrestrial planets: scanning their surfaces remotely

1989 ◽  
Vol 53 (370) ◽  
pp. 135-151 ◽  
Author(s):  
Roger G. Burns
Keyword(s):  
Near Infrared ◽  
Surface Composition ◽  
Reflectance Spectra ◽  
Terrestrial Planets ◽  
The Moon ◽  
Spectral Measurements ◽  
Absorption Bands ◽  
Bearing Materials ◽  
Solar System Bodies ◽  
Surface Mineralogy

AbstractSpectral measurements of sunlight reflected from planetary surfaces, when correlated with experimental visible-near-infrared spectra of rock-forming minerals, are being used to detect transition metal cations, to identify constituent minerals, and to determine modal mineralogies of regoliths on terrestrial planets. Such remote-sensed reflectance spectra measured through earth-based telescopes may have absorption bands in the one micron and two micron wavelength regions which originate from crystal field transitions within Fe2+ ions. Pyroxenes with Fe2+ in M2 positions dominate the spectra, and the resulting 1 μm versus 2 µm spectral determinative curve is used to identify compositions and structure-types of pyroxenes on surfaces of the Moon, Mercury, and asteroids, after correcting for experimentally-determined temperature-shifts of peak positions. Olivines and Fe2+-bearing plagioclase feldspars also give diagnostic peaks in the 1 µm region, while tetrahedral Fe2+ in glasses absorb in the 2 µm region as well. Opaque ilmenite, spinel and metallic iron phases mask all of these Fe2+ spectral features. Laboratory studies of mixed-mineral assemblages enable coexisting Fe2+ phases to be identified in remote-sensed reflectance spectra of regoliths. Thus, noritic rocks in the lunar highlands, troctolites in central peaks of impact craters such as Copernicus, and high-Ti and low-Ti mare basalts have been mapped on the Moon's surface by telescopic reflectance spectroscopy. The Venusian atmosphere prevents remote-sensed spectral measurements of its surface mineralogy, while atmospheric CO2 and ferric-bearing materials in the regolith on Mars interfere with pyroxene characterization in bright- and dark-region spectra. Reflectance spectral measurements of several meteorite types, including specimens from Antarctica, are consistent with a lunar highland origin for achondrite ALHA 81005 and a martian origin for shergottite EETA 79001, although source regions may not be outermost surfaces of the Moon and Mars. Correlations with asteroid reflectance spectra suggest that Vesta is the source of basaltic achondrites, while wide ranges of olivine/pyroxene ratios are inconsistent with an ordinary-chondrite surface composition of many asteroids. Visible-near-infrared spectrometers are destined for instrument payloads in future spacecraft missions to neighbouring solar system bodies.

scholarly journals Effect of Lunar Complex Illumination on In Situ Measurements Obtained Using Visible and Near-Infrared Imaging Spectrometer of Chang’E-4

2021 ◽  
Vol 13 (12) ◽  
pp. 2359
Author(s):  
Jiafei Xu ◽  
Meizhu Wang ◽  
Rong Wang ◽  
Qi Feng ◽  
Honglei Lin ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Specular Reflection ◽  
In Situ Measurements ◽  
The Moon ◽  
Spectral Measurements ◽  
Near Infrared Imaging ◽  
Imaging Spectrometer

In-situ measurements of the spectral information on the lunar surface are of significance to study the geological evolution of the Moon. China’s Chang’E-4 (CE-4) Yutu-2 rover has conducted several in-situ spectral explorations on the Moon. The visible and near-infrared imaging spectrometer (VNIS) onboard the rover has acquired a series of in-situ spectra of the regolith at the landing site. In general, the mineralogical research of the lunar surface relies on the accuracy of the in-situ data. However, the spectral measurements of the Yutu-2 rover may be affected by shadows and stray illumination. In this study, we analyzed 106 CE-4 VNIS spectra acquired in the first 24 lunar days of the mission and noted that six of these spectra were affected by the shadows of the rover. Therefore, a method was established to correct the effects of the rover shadow on the spectral measurements. After shadow correction, the FeO content in the affected area is corrected to 14.46 wt.%, which was similar to the result calculated in the normal regolith. Furthermore, according to the visible images, certain areas of the explored sites were noted to be unusually bright. Considering the reflectance, geometric information, and shining patterns of the multi-layer insulation (MLI), we examined the influence of the specular reflection of the MLI on the bright spot regionsd , and found that the five sets of data were likely not affected by the specular reflection of the MLI. The results indicated that the complex illumination considerably influences the in situ spectral data. This study can provide a basis to analyze the VNIS scientific data and help enhance the accuracy of interpretation of the composition at CE-4 landing sites.

Vestoid surface composition from analysis of faint absorption bands in visible reflectance spectra

Icarus ◽  
2008 ◽  
Vol 195 (2) ◽  
pp. 649-662 ◽  
Author(s):  
D.I. Shestopalov ◽  
L.A. McFadden ◽  
L.F. Golubeva ◽  
V.M. Khomenko ◽  
L.O. Gasanova
Keyword(s):  
Surface Composition ◽  
Reflectance Spectra ◽  
Absorption Bands ◽  
Visible Reflectance

The effects of graphite and particles size on reflectance spectra of silicates

2021 ◽  
Author(s):  
Enrico Bruschini ◽  
Cristian Carli ◽  
Fabrizio Capaccioni ◽  
Mathieu Vincendon ◽  
Anne-Cécile Buellet ◽  
...  
Keyword(s):  
Near Infrared ◽  
Weight Ratio ◽  
Remote Sensing Data ◽  
Reflectance Spectra ◽  
Strong Impact ◽  
Absorption Bands ◽  
Graphite Content ◽  
History Of ◽  
The One ◽  
Silicate Materials

<p>Mercury is characterized by a globally low reflectance associated with remarkably low iron contents. Among several proposed hypothesis, to date, the most convincing explanation of the low reflectance of Mercury invokes mixing of an ancient graphite-rich crust with overlying volcanic materials via impact processes and/or assimilation of carbon into rising magmas during secondary crustal formation (e.g. Peplowski et al.2016). Even though until now graphite has not been directly observed, there are strong evidences suggesting its presence on Mercury’s surface (e.g. Denevi et al.2009; Peplowski et al.2011). The actual presence of graphite within Mercury soil may have several implications, e.g. on the late accretion history of Mercury (Hyodo et al.2021; Murchie et al.2015) or on hollow formation (Blewett et al.2016). Moreover, silicates are often associated to carbon phases in some achondrites (e.g. ureilite, Nestola et al.2020, and references therein). Evaluating in a systematic way the effect of graphite on visible and near-infrared spectroscopy of mafic mineral absorptions is thus of interest to improve our understanding of Mercury remote sensing data, and to make progress in our capability to associate carbon-rich stony meteorites to their parent bodies. Mixing graphite with silicate materials is thought to basically decrease the contrast of reflectance spectra of these materials (Murchie et al.2015). Nevertheless, systematic works addressing the influence of graphite-silicate mixtures on their reflectance spectra are still lacking. Here we mixed microcrystalline graphite with a suite of silicate materials and measured their VNIR reflectance spectra. We selected three silicate end-member compositions, namely: 1) a synthetic glass with chemical composition close to the one inferred for of the volcanic products emplaced in the Mercury’s northern volcanic plains (Vetere et al.2017), 2) a Mg-rich Gabbronorite with FeO < 3% (Secchiari et al.2018) and 3) a hawaiitic basalt (Pasquarè et al.2008). To decouple the effect of granulometry and graphite content, we produced and analyzed different granulometric classes (ranging between <50 μm and 250μm) for each end-member. In a second stage, we selected three granulometric classes (<50 μm, 75-100 μm and 150-180 μm) for each end member and we added graphite producing different samples with graphite – silicate weight ratio between 0-5% (0%, 1%, 2%, 3%, 4% and 5%) in order to encompass the inferred graphite content in Mercury’s surface (Klima et al.2018). The results of our work confirm that graphite strongly decreases the contrast of the reflectance spectra of the silicate-graphite mixtures and, in most cases, has a negligible effect on the shift of the absorption bands. However the slopes of the reflectance spectra are greatly affected by the graphite content, which tends to decrease the slope of the spectra. Our systematic study will allow to gain a better understanding of the reflectance spectra of materials mixed with opaque phases in meteorites, space-weathered surfaces and rocky planetary bodies. In particular, this investigation is expected to have a strong impact on the interpretation of reflectance measurements of Mercury. Acknowledgments: Part of this research was supported by ASI-INAF Simbio-sys agreement. E.B. and C.C. are supported also by ASI-INAF 2018-16-HH.0 (Ol-BODIES) agreement.</p>

The Surface Composition of Terrestrial Planets

2019 ◽  
Author(s):  
Nicolas Mangold ◽  
Jessica Flahaut ◽  
Véronique Ansan
Keyword(s):  
Surface Composition ◽  
Climatic Variability ◽  
Terrestrial Planets ◽  
The Moon ◽  
Planetary Body ◽  
Climate Conditions ◽  
Hydrous Minerals ◽  
Alteration Processes ◽  
Formation And Evolution

Planetary surface compositions are fundamental to an understanding of both the interior activity through differentiation processes and volcanic activity and the external evolution through alteration processes and accumulations of volatiles. While the Moon has been studied since early on using ground-based instruments and returned samples, observing the surface composition of the terrestrial planets did not become practical until after the development of orbital and in situ missions with instruments tracking mineralogical and elemental variations. The poorly evolved, atmosphere-free bodies like the Moon and Mercury enable the study of the formation of the most primitive crusts, through processes such as the crystallization of a magma ocean, and their volcanic evolution. Nevertheless, recent studies have shown more diversity than initially expected, including the presence of ice in high latitude regions. Because of its heavy atmosphere, Venus remains the most difficult planetary body to study and the most poorly known in regards to its composition, triggering some interest for future missions. In contrast, Mars exploration has generated a huge amount of data in the last two decades, revealing a planet with a mineralogical diversity close to that of the Earth. While Mars crust is dominated by basaltic material, recent studies concluded for significant contributions of more felsic and alkali-rich igneous material, especially in the ancient highlands. These ancient terrains also display widespread outcrops of hydrous minerals, especially phyllosilicates, which are key in the understanding of past climate conditions and suggest a volatile-rich early evolution with implications for exobiology. Recent terrains exhibit a cryosphere with ice-rich landforms at, or close to the surface, of mid- and high latitudes, generating a strong interest for recent climatic variability and resources for future manned missions. While Mars is certainly the planetary body the most similar to Earth, the observation of specific processes such as those linked to interactions with solar wind on atmosphere-free bodies, or with a thick acidic atmosphere on Venus, improve our understanding of the differences in evolution of terrestrial bodies. Future exploration is still necessary to increase humankind’s knowledge and further build a global picture of the formation and evolution of planetary surfaces.

scholarly journals Uncertainty Introduced by Darkening Agents in the Lunar Regolith: An Unmixing Perspective

2021 ◽  
Vol 13 (22) ◽  
pp. 4702
Author(s):  
Marcel Hess ◽  
Thorsten Wilhelm ◽  
Christian Wöhler ◽  
Kay Wohlfarth
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Lunar Regolith ◽  
Spectral Unmixing ◽  
Probabilistic Methods ◽  
Space Weathering ◽  
The Moon ◽  
Absorption Bands ◽  
Diagnostic Features ◽  
Infrared Wavelength

On the Moon, in the near infrared wavelength range, spectral diagnostic features such as the 1-μm and 2-μm absorption bands can be used to estimate abundances of the constituent minerals. However, there are several factors that can darken the overall spectrum and dampen the absorption bands. Namely, (1) space weathering, (2) grain size, (3) porosity, and (4) mineral darkening agents such as ilmenite have similar effects on the measured spectrum. This makes spectral unmixing on the Moon a particularly challenging task. Here, we try to model the influence of space weathering and mineral darkening agents and infer the uncertainties introduced by these factors using a Markov Chain Monte Carlo method. Laboratory and synthetic mixtures can successfully be characterized by this approach. We find that the abundance of ilmenite, plagioclase, clino-pyroxenes and olivine cannot be inferred accurately without additional knowledge for very mature spectra. The Bayesian approach to spectral unmixing enables us to include prior knowledge in the problem without imposing hard constraints. Other data sources, such as gamma-ray spectroscopy, can contribute valuable information about the elemental abundances. We here find that setting a prior on TiO2 and Al2O3 can mitigate many of the uncertainties, but large uncertainties still remain for dark mature lunar spectra. This illustrates that spectral unmixing on the Moon is an ill posed problem and that probabilistic methods are important tools that provide information about the uncertainties, that, in turn, help to interpret the results and their reliability.

scholarly journals Space Weathering of S-Complex Asteroids Manifested in the UV/Blue: Recent Insights and Future Directions

2015 ◽  
Vol 10 (S318) ◽  
pp. 201-205
Author(s):  
Faith Vilas ◽  
Amanda R. Hendrix
Keyword(s):  
Spectral Reflectance ◽  
Near Infrared ◽  
Uv Absorption ◽  
Reflectance Spectra ◽  
Absorption Feature ◽  
Space Weathering ◽  
The Moon ◽  
Future Directions ◽  
Absorption Features ◽  
Weathering Effects

AbstractSpace weathering affects reflectance spectra of the Moon and S-complex asteroids by spectral bluing (increasing reflectance with decreasing wavelength) of their surface materials at UV/blue (less than 400 nm) wavelengths. This spectral bluing is attributed to a degradation of the UV absorption feature seen in spectral reflectance of olivine as a result of the creation of nanophase (npFe0) iron. We have modeled the effect of the addition of small amounts of npFe0 intimately mixed with particles from a hypothetical material and a terrestrial basalt. The addition of 0.0001% npFe0 affects the reflectance at these UV/blue wavelengths, while the addition of 0.01% is required to see the visible/near infrared reddening and diminution of VNIR absorption features. Thus, the UV/blue spectral reflectance characteristics allow earlier detection of the onset of space weathering effects.

scholarly journals Photometric properties of lunar regolith revealed by the Yutu-2 rover

2020 ◽  
Vol 638 ◽  
pp. A35 ◽  
Author(s):  
Honglei Lin ◽  
Yazhou Yang ◽  
Yangting Lin ◽  
Yang Liu ◽  
Yong Wei ◽  
...  
Keyword(s):  
Near Infrared ◽  
Surface Composition ◽  
Lunar Regolith ◽  
Remote Sensing Data ◽  
Landing Site ◽  
Ground Truth ◽  
Wavelength Dependence ◽  
Forward Scattering ◽  
Small Scale ◽  
The Moon

Context. The surface composition of the Moon has mainly determined based on the visible and near-infrared spectra achieved from orbits and/or landing sites, and the spectroscopic analysis is based on photometric properties of the topmost lunar regolith. However, the lack of a ground truth for the photometric parameters of the undisturbed lunar surface has limited accurate applications of spectral observations. Aims. Here we report the photometric properties of the small-scale (i.e., centimeter level) undisturbed lunar regolith around the Chang’E-4 landing site, determined from a series of photometric experiments conducted by the rover Yutu-2. Methods. The simplified Hapke model was used to derive the photometric properties. The micro-topographic effect on the spectral measurements was corrected for the first time in the in situ photometric investigations on the Moon, which improves the accuracy of the derived photometric parameters. Results. The single-scattering albedo w and two parameters (b, c) of the Henyey-Greenstein phase function were derived, and they show a wavelength dependence. The regolith at the Chang’E-4 landing site exhibits strong forward scattering according to the retrieved c values, and the higher asymmetry parameter indicates that the regolith here is more strongly forward scattering than the Apollo lunar soil samples. The derived photometric parameters can serve as ground truth and can be used in the radiative transfer modeling analysis of the orbital remote-sensing data.

scholarly journals Surface Composition of the Galilean Satellites from Galileo Near-Infrared Mapping Spectroscopy

1998 ◽  
Vol 11 (2) ◽  
pp. 1078-1081
Author(s):  
R.W. Carlson ◽  
W.D. Smythe ◽  
D.L. Matson ◽  
R. Lopes-Gautier ◽  
J. Hui ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Near Infrared ◽  
Surface Composition ◽  
Spectral Feature ◽  
Surface Compound ◽  
Galilean Satellites ◽  
Absorption Bands ◽  
Hydrous Minerals ◽  
Water Ice ◽  
High Concentrations

AbstractThe Galileo Near Infrared Mapping Spectrometer (NIMS) is currently obtaining spectral maps of Jupiter’s moons to determine the composition and spatial distribution of minerals on the satellite surfaces. Sulfur dioxide, as a frost or ice, covers much of Io’s surface, except in hot volcanic areas. A weak spectral feature at 3.15 μm suggests the presence of an OH containing surface compound (hydroxide, hydrate, or water) and a broad absorption above 1 μm is reasonably attributed to iron-containing minerals, such as feldspars and pyrite. Water is the dominant molecule covering Europa’s surface, occurring as ice but also as a hydrate. The trailing side shows high concentrations of these hydrous minerals, whose identifications are not yet established. Ganymede’s surface exhibits water absorption bands, largely due to ice but hydrates are also present. A dark component is present, but with a smaller proportion compared to Callisto. Some of the non-ice features seen on Ganymede are similar to those found in Callisto’s spectra (see below). Among the icy Galilean satellites, Callisto shows the least amount of water ice, covering about 10% of the surface in patchy concentrations. Most of the surface is covered with unidentified (as yet) dark minerals. The exposed ice is often associated with impact craters, implying that the darker material exists as a blanket over more pure ice. Non-ice spectral features at 3.88, 4.03, 4.25, and 4.57 μm are present in Callisto’s spectra (and some of these appear in Ganymede’s spectra), each with different spatial distributions. Laboratory spectra suggest that the 4.25-μm feature is due to carbon dioxide which is trapped in the surface grains. The band at 4.03 μm may be due to sulfur dioxide, which probably originated from Io. Molecules containing CN, SH, SiH, and perhaps deuterated constituents are candidates for the other features, some of which could be derived from shock-heated and modified material from impacts, perhaps of carbonaceous composition. There is evidence for the presence of hydrated minerals on Callisto, based on water band shifts and shapes.

Exploring the Solar System

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Planetary Systems ◽  
Interplanetary Dust ◽  
Terrestrial Planets ◽  
The Moon ◽  
System P ◽  
Asteroids And Comets

In this chapter, the author summarizes the properties of the Solar System, and how these were uncovered. Over centuries, the arrangement and properties of the Solar System were determined. The distinctions between the terrestrial planets, the gas and ice giants, and their various moons are discussed. Whereas humans have walked only on the Moon, probes have visited all the planets and several moons, asteroids, and comets; samples have been returned to Earth only from our moon, a comet, and from interplanetary dust. For Earth and Moon, seismographs probed their interior, whereas for other planets insights come from spacecraft and meteorites. We learned that elements separated between planet cores and mantels because larger bodies in the Solar System were once liquid, and many still are. How water ended up where it is presents a complex puzzle. Will the characteristics of our Solar System hold true for planetary systems in general?

Sign in / Sign up

Export Citation Format

Share Document