Aqueous alteration of the Bali CV3 chondrite: Evidence from mineralogy, mineral chemistry, and oxygen isotopic compositions

Keller, L. P.; Thomas, K. L.; Clayton, Robert N.; Mayeda, T. K.; Dehart, J. M.; McKay, D. S.

doi:10.1016/0016-7037(94)90252-6

Cited by 81 publications

(86 citation statements)

References 19 publications

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“…If this feature is real, then anhydrous carbonaceous meteorites, such as ureilites, CO3, and CV3 chondrites are poor analogues for Lutetia surface composition. Although some CO3 and CV3 meteorites show signatures of aqueous alteration on a microscopic scale (Tomeoka & Buseck 1982Keller et al 1994), on a macroscopic scale they can be considered as anhydrous, since their reflectance spectra lack hydration bands at 2.7-3 μm (Larson et al 1979;Jones 1988). The 2.7 μm bands due to O-H stretch in hydrated silicates are absent in laboratory reflectance spectra of CO3 and CV3 chondrites, while weak bands at 3 μm sometimes detectable in their spectra are due to adsorbed water (Jones 1988).…”

Section: Observations Data Reduction and Discussionmentioning

confidence: 99%

New visible spectra and mineralogical assessment of (21) Lutetia, a target of the Rosetta mission

Lazzarin

Marchi

Moroz

et al. 2009

A&A

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The Rosetta spacecraft, launched on March 2nd 2004, in the course of its journey to the comet 67P/Churyumov-Gerasimenko (encounter foreseen in 2014), will fly past two asteroids: (2867) Steins and (21) Lutetia. On September 5th 2008 (2867) Steins was encountered. In this paper, we present two visible spectra of (21) Lutetia of different spectral resolutions covering the spectral ranges where possible absorption bands were previously revealed by Lazzarin and collaborators. We confirm detection of a broad complex feature between 0.45 and 0.55 μm and two narrower features around 0.47 and 0.52 μm. We discuss possible assignments of these bands and suggest that they might originate from electronic transitions in pyroxenes, although unambiguous identification is difficult and the published thermal infrared (TIR) spectrum of (21) Lutetia suggests that pyroxene cannot be the dominant silicate component at its surface. Furthermore, we discuss the published spectra of (21) Lutetia in the range from near-UV to thermal infrared. We conclude that carbonaceous meteorites (chondrites and achondrites) appear to be the closest meteorite analogues of (21) Lutetia, based on the observed spectral features. Among these meteorites, metal-rich carbonaceous chondrites seem to be the most plausible analogue materials.

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Section: Observations Data Reduction and Discussionmentioning

confidence: 99%

New visible spectra and mineralogical assessment of (21) Lutetia, a target of the Rosetta mission

Lazzarin

Marchi

Moroz

et al. 2009

A&A

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“…Several reports about the discovery of aqueous phases in CV chondrites exist (e.g., Bunch and Chang, 1979;Buseck, 1982, 1990;Cohen et al, 1983;Fegley and Post, 1985;Hashimoto and Grossman, 1987;Liu et al, 1988;Keller and Buseck, 1989, 1990b, 1991Graham and Lee, 1992;Zolensky et al, 1993;Keller et al, 1994;Kimura and Ikeda, 1996;Tanimura et al, 1996;Brearley, 1997b), and a synopsis on phyllosilicates identified in CV3 chondrites is given by Krot et al (1995). For the formation of phyllosilicates in the matrix of CV chondrites, parent body alteration has been suggested.…”

Section: Co and CV Chondritesmentioning

confidence: 99%

Aqueous alteration of carbonaceous chondrites: Evidence for preaccretionary alteration—A review

Bischoff

1998

Meteorit & Planetary Scien

131

113

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Abstract-In most groups of carbonaceous chondrites, minerals occur that are formed due to aqueous alteration in the nebula and/or within meteorite parent bodies. For determining the evolution of materials in the early solar system, it is of significant importance to clearly identify evidence for either nebular or planetary aqueous alteration. Therefore, results fi-om the study of chondrites have fundamental implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes.Considering the topic of this review, it is important to define nebular and parent body processes. The solar nebula activity should include condensation processes of high-and low-temperature components as well as processes of chemical fractionation and grain-size sorting, mixing of solids and gas, and interactions between early formed solids with the remaining gas; but it should exclude processes that occurred in small uncompacted protoplanetary objects that may have been totally destroyed again before accretion of the final meteorite parent bodies. Therefore, the term "preaccretionary" instead of "nebula" is used in this paper to include all these processes that may have occurred in small precursor planetesimals.Currently, there is no doubt that parent body aqueous alteration is a fundamental process in the evolution of several groups of carbonaceous chondrites. However, due to textural and mineralogical observations and chemical analyses, strong arguments have been found also indicating preaccretionary aqueous alteration of distinct components in carbonaceous chondrites. In this paper, evidence for preaccretionary aqueous alteration in carbonaceous chondrites and their components taken from previous studies is discussed in detail.The strongest evidence for preaccretionary alteration comes from studies of CM chondrites. The survival of highly unequilibrated mineral assemblages in accretionary rims, and sharp contacts between chondrule glass and surrounding phyllosilicates, are only two important arguments for preaccretionary alteration features among many others discussed in the paper. Similar observations were also made in CR, CH and related chondrites. Due to the small abundance of water-bearing phases in CO and CV chondrites, the origin of phyllosilicates in these groups is less clear. A preaccretionary origin of hydrous phases in Ca-Al-rich inclusions (CAIs) has also been suggested by several scientists. In CI chondrites, no strong indications for such processes have been found, mainly due to heavy brecciation and severe parent body alteration.

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“…Hydrothermal alteration experiments of enstatite were carried out at temperatures of 100, 200, and 300 °C, and for References: (1) Tomeoka and Buseck (1988); (2) Brearley (1992); (3) Akai (1980); (4) Barber (1981); (5) MacKinnon and Zolensky (1984); (6) Tomeoka and Buseck (1985); (7) Zega et al (2003); (8) Zega et al (2004); (9) Weisberg et al (1993); (10) Hashimoto and Grossman (1987); (11) Tomeoka and Buseck (1990); (12) Keller and Buseck (1990b); (13) Keller et al (1994); (14) Lee et al (1996); (15) Keller and Buseck (1990a); (16) Brearley (1993).…”

Section: Hydrothermal Alteration Experimentsmentioning

confidence: 99%

“…For example, the matrices of CI chondrites consist mainly of serpentine, saponite, and ferrihydrite, the matrices of CM chondrites consist mainly of serpentine and tochilinite, and the matrices of hydrated CV chondrites contain saponite. Mineralogical and petrological studies (e.g., Buseck 1988, 1990;Keller and Buseck 1990b;Keller et al 1994;Zolensky et al 1989Zolensky et al , 1993Zega et al 2003;Jones and Brearley 2006) and oxygen isotopic studies (e.g., Clayton and Mayeda 1999) suggest that the differences in hydrous minerals may have resulted from differences in alteration conditions, such as temperature, pH, compositions of aqueous fluids, oxygen fugacity, and water/rock ratio, on the meteorite parent bodies.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal alteration experiments of enstatite: Implications for aqueous alteration of carbonaceous chondrites

Tomeoka

2007

Meteorit & Planetary Scien

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Abstract-Enstatite is one of the major constituent minerals in carbonaceous chondrites. Hydrothermal alteration experiments (26 in total) of enstatite were carried out at pH 0, 6, 7, 12, 13, and 14, at temperatures of 100, 200, and 300 °C, and for run durations of 24, 72, 168, and 336 h in order to provide constraints on the aqueous-alteration conditions of the meteorites. The recovered samples were studied in detail by using powder X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).Under acidic and mildly acidic conditions (pH 0, 6), no significant alteration occurred, whereas under neutral to alkaline conditions (pH 7-14), serpentine and saponite formed in various proportions by replacing enstatite. At 300 °C for 168 h, serpentine formed under neutral to moderately alkaline conditions (pH 7, 12), and serpentine and saponite formed as unit cell-scale coherent intergrowths under highly alkaline conditions (pH 13, 14). The amounts of phyllosilicates have a tendency to increase with increasing pH, temperature, and run duration. There is also a tendency for saponite to form at higher pH and temperature and under longer run-durations than serpentine.The results indicate that alteration of enstatite is strongly dependent on the experimental conditions, especially pH. They suggest that CM chondrites experienced aqueous alteration under neutral to alkaline conditions, whereas CV and CI chondrites experienced aqueous alteration under more alkaline conditions. The results also suggest that aqueous alteration in CI chondrites occurred at higher temperatures than in CM chondrites, and aqueous alteration in CV chondrites occurred at even higher temperatures than in CI chondrites.

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Aqueous alteration of the Bali CV3 chondrite: Evidence from mineralogy, mineral chemistry, and oxygen isotopic compositions

Cited by 81 publications

References 19 publications

New visible spectra and mineralogical assessment of (21) Lutetia, a target of the Rosetta mission

New visible spectra and mineralogical assessment of (21) Lutetia, a target of the Rosetta mission

Aqueous alteration of carbonaceous chondrites: Evidence for preaccretionary alteration—A review

Hydrothermal alteration experiments of enstatite: Implications for aqueous alteration of carbonaceous chondrites

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