Water combinations on the surface of the asteroid 4 Vesta

Prokof’eva-Mikhailovskaya, V. V.; Rublevskii, A. N.; Bochkov, V. V.

doi:10.3103/s0190271708010221

Cited by 3 publications

(2 citation statements)

References 29 publications

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“…2003; Prokof’eva‐Mikhailovskaya et al. 2008), but they have not been detected within HED meteorites so far. Still, fayalite may form from the reaction between H 2 O and SiO 2 with metal and magnetite (Equation ; Zolotov et al.…”

Section: Discussionmentioning

confidence: 98%

How do secondary iron enrichments form within basaltic eucrites? An experimental approach

Rombeck

Vollmer

Roszjar

et al. 2021

Meteorit & Planetary Scien

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Some basaltic eucrites and basaltic lithologies in howardites derived from the asteroid 4 Vesta exhibit unusual secondary veinlet textures consisting mostly of fayalitic olivine and Fe‐enrichments within pyroxenes. Recent studies discussed the formation of these Fe‐rich phases either by interaction with a vapor and/or liquid phase (metasomatism), or by a high‐temperature melting process. We therefore performed a series of heating and hydrothermal experiments with liquids of different compositions on natural pyroxene crystals (augite and orthopyroxene) to evaluate these contrasting hypotheses. The results of the heating experiments show that incongruent melting of pyroxenes at about 1070 °C causes textures that are very similar to those observed in the meteorites. We conclude that a part of the natural secondary veins might be explained by heating processes at similar temperatures. The hydrothermal experiments with aqueous liquids of different Fe‐enriched compositions clearly indicate ion exchange reactions resulting in partial Fe‐enrichments of the pyroxene. Interestingly, these Fe‐enrichments occurred independent of the Fe content of the liquid, which can be explained by an internal origin of Fe from the pyroxenes. In one hydrothermal experiment of augite with Fe‐oxalate solution, deposition of fayalitic olivine was observed. From our experimental observations, we conclude that aqueous liquids are plausible candidates for explaining the deposition of Fe‐enrichments and fayalitic olivine inside the fractures of pyroxene. However, we cannot rule out a high‐temperature melting process slightly above the peritectic point of pyroxene to explain a fraction of observed secondary Fe‐enrichments.

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Section: Discussionmentioning

confidence: 98%

How do secondary iron enrichments form within basaltic eucrites? An experimental approach

Rombeck

Vollmer

Roszjar

et al. 2021

Meteorit & Planetary Scien

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“…If the crust has been locally weathered by aqueous fluids, hydrated and/or hydroxylated phases should have been deposited at least locally in other parts of the hydrothermal system(s) (i.e., depending of the temperature of the fluids). Interestingly, such phases have been inferred in some areas of Vesta by Earth-based observations (Hasegawa et al, 2003;Prokof'eva-Mikhailovskaya et al, 2008). In September 2007, the Dawn spacecraft was launched to the asteroid belt and will begin studying Vesta in 2011 (Russell et al, 2007).…”

Section: Pristine Pxmentioning

confidence: 96%

Possible fluid–rock interactions on differentiated asteroids recorded in eucritic meteorites

Barrat

Yamaguchi

Bunch

et al. 2011

Geochimica et Cosmochimica Acta

104

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The eucritic meteorites are basaltic rocks that originate from the upper part of the crust of some small bodies as exemplified possibly by asteroid 4-Vesta. A few eucrites appear to have been modified by different degrees of a late stage alteration process that caused significant variations in mineralogy. Three distinct alteration stages are identified: (1) Fe-enrichment along the cracks that cross cut the pyroxene crystals ("Fe-metasomatism"); secondary olivine and minute amounts of troilite are found only occasionally in cracks at this stage; (2) deposits of Fe-rich olivine (Fa 64-86 ) and minor amounts of troilite are frequent inside the cracks; sporadic secondary Ca-rich plagioclase (An 97-98 ) is associated with the fayalitic olivine; (3) at this stage, the Fe-enrichment of the pyroxene is accompanied by a marked Al-depletion; moreover, secondary Ca-rich plagioclase is more frequent and partly fills some cracks or rims of the primary plagioclase crystals. The composition of the secondary phases on one hand, the lack of incompatible trace element enrichment in the metasomatized pyroxenes on the other hand, rule out a silicate melt as the metasomatic agent. Although no hydrous phase has been yet identified in the studied samples, aqueous fluids are plausible candidates for explaining the deposits of ferroan olivine and anorthitic plagioclase inside the fractures of the studied unequilibrated eucrites.

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Comparison of feature sizes on the surface of the asteroid 4 Vesta determined using ground-based and space observations

Prokofieva-Mikhailovskaia

Rublevskii

2013

Kinemat. Phys. Celest. Bodies

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Water combinations on the surface of the asteroid 4 Vesta

Cited by 3 publications

References 29 publications

How do secondary iron enrichments form within basaltic eucrites? An experimental approach

How do secondary iron enrichments form within basaltic eucrites? An experimental approach

Possible fluid–rock interactions on differentiated asteroids recorded in eucritic meteorites

Comparison of feature sizes on the surface of the asteroid 4 Vesta determined using ground-based and space observations

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