Fluorescent accessory phases in the carbonaceous matrix of ureilites

Berkley, J. L.; Taylor, G. J.; Keil, K.; Healey, J.T.

doi:10.1029/gl005i012p01075

Cited by 22 publications

(22 citation statements)

References 7 publications

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“…After breaking open the first sample, we noted that the gray matrix contains locally abundant aggregates of purple halite (NaCl) crystals, measuring up to 3 mm in diameter. To the best of our knowledge, megascopic halite has not been previously seen in any extraterrestrial sample, although microscopic halite has been reported in several meteorites (6)(7)(8).…”

Section: V)mentioning

confidence: 76%

Asteroidal Water Within Fluid Inclusion-Bearing Halite in an H5 Chondrite, Monahans (1998)

Zolensky

Bodnar

Gibson

et al. 1999

Science

178

128

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Crystals of halite and sylvite within the Monahans (1998) H5 chondrite contain aqueous fluid inclusions. The fluids are dominantly sodium chloride-potassium chloride brines, but they also contain divalent cations such as iron, magnesium, or calcium. Two possible origins for the brines are indigenous fluids flowing within the asteroid and exogenous fluids delivered into the asteroid surface from a salt-containing icy object.

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Section: V)mentioning

confidence: 76%

Asteroidal Water Within Fluid Inclusion-Bearing Halite in an H5 Chondrite, Monahans (1998)

Zolensky

Bodnar

Gibson

et al. 1999

Science

178

128

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“…Petrologic and compositional information on ureilites is from Berkley and Jones (1982), Berkley et al (1976Berkley et al ( , 1978Berkley et al ( , 1980, Binz et al (1975), Boynton et al (1976), Cohen et al (2004), Goodrich and Berkley (1986), Goodrich et al (2004), Higuchi et al (1976), Ikeda et al (2000Ikeda et al ( , 2003, Jaques and Fitzgerald (1982), Janssens et al (1987), Singletary and Grove (2003), Sinha et al (1997), Spitz and Boynton (1991), Takeda (1987), Wang and Lipschutz (1995), Warren and Kallemeyn (1989b), Warren et al (2006), and Wasson et al (1976).…”

Section: Ureilitesmentioning

confidence: 98%

Achondrites

Mittlefehldt

2014

Treatise on Geochemistry

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“…High-temperature saline melts have also been described at the margins of dolerite dykes that intrude evaporites in Irkutsk (Pavlov, 1970). Berkley et al (1978) described halite, sylvite, and chlorapatite in ureilites. These phases were concentrated in interstitial areas of the meteorites, together with glass and quench crystallites, and were thought to have crystallized from igneous liquids.…”

Section: Formation Conditions Of the Assemblagementioning

confidence: 99%

A halite‐siderite‐anhydrite‐chlorapatite assemblage in Nakhla: Mineralogical evidence for evaporites on Mars

Bridges

Grady

1999

Meteorit & Planetary Scien

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Abstract-We report the results of a study of a halite-siderite-anhydrite-chlorapatite assemblage in the Shergotty-Nakhla-Chassigny (SNC) Martian meteorite Nakhla. These minerals are found associated with each other in interstitial areas, with halite often being adjacent to or enclosing siderite. We suggest the halite and other minerals are Martian in origin because (1) the conditions of fall preclude significant amounts of terrestrial contamination or weathering having taken place; (2) textures indicate that the minerals within this assemblage crystallized at the same stage as some silicate and oxide minerals within the Nakhla parent; and (3) the association with siderite, which previous studies have shown has C and 0-isotopic compositions incompatible with an origin on the Earth. Siderite has the range of compositions: CaC03, 0.1-5.7; MgC03, 2.0-40.9; FeC03,23.2-87.0; MnC03,l .O-39.9 mol%. There are two compositional groupings: high-MnC03 (230 mol%) and low-MnCO3high-FeCO3, with a gap identified between the two. This may be a miscibility gap or, alternatively, the two compositional groupings may mark separate generations of carbonate. We have not found any textural evidence for the latter explanation, but acceptance of the presence of a miscibility gap would require independent work on Fe-Mn carbonates to verify its existence. Trace element abundances have been determined by ion microprobe analysis on three siderite and one anhydrite grains. Siderite has light rare earth elements (2.2-7.3 x C1) greater than heavy rare earth elements (0.32-0.79 x Cl) without Ce or Eu anomalies, and the anhydrite has a similar pattern. These abundances reflect the source composition rather than partitioning or complexing controls. They are not typical of hydrothermal signatures which generally do not have such smooth REE abundance patterns. The nature of the mineral assemblage suggests that its source rocks on Mars were evaporites. These may be common in the craters and flood plains of the Martian southern highlands. Two models are suggested in this paper to explain the incorporation of evaporitic material into the Nakhla igneous parent. It may have happened as a low-temperature process (<200 "C) by crystallisation from an aqueous fluid. An origin at low temperature is compatible with the available experimental data on siderite stability. Alternatively, we suggest evaporitic material may have been incorporated into the Nakhla parent while melt was still present and crystallized -800 "C. The latter model can more readily explain the trace element abundances and also the siderite textures that imply intergrowth with residual interstitial melt. Both high-and low-temperature models are consistent with the presence of evaporite sediments on Mars.

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Fluorescent accessory phases in the carbonaceous matrix of ureilites

Cited by 22 publications

References 7 publications

Asteroidal Water Within Fluid Inclusion-Bearing Halite in an H5 Chondrite, Monahans (1998)

Asteroidal Water Within Fluid Inclusion-Bearing Halite in an H5 Chondrite, Monahans (1998)

Achondrites

A halite‐siderite‐anhydrite‐chlorapatite assemblage in Nakhla: Mineralogical evidence for evaporites on Mars

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