Investigations into an unknown organism on the martian meteorite Allan Hills 84001

Steele, A.; Goddard, D. T.; Stapleton, David C.; Toporski, J.; Peters, V. N.; Bassinger, Virginia; Sharples, George P.; Wynn‐Williams, D. D.; McKay, D. S.

doi:10.1111/j.1945-5100.2000.tb01772.x

Cited by 55 publications

(30 citation statements)

References 17 publications

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“…The current balance of evidence does not strongly support the biogenic theory of origin for ALH84001 carbonates (Scott, 1999;Steele et al, 2000;Kathie et al, 2000;Bradley et al, 1998;. The best argument for a biological origin rests with the morphology of some of the magnetite grains.…”

Section: Suggested Relic Biological Activity In Alh84001mentioning

confidence: 88%

Alteration Assemblages in Martian Meteorites: Implications for Near-Surface Processes

Bridges

Catling

Saxton

et al. 2001

Space Sciences Series of ISSI

128

201

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Abstract. The SNC (Shergotty-Nakhla-Chassigny) meteorites have recorded interactions between martian crustal fluids and the parent igneous rocks. The resultant secondary minerals -which comprise up to ~ 1 vol.% of the meteorites -provide information about the timing and nature of hydrous activity and atmospheric processes on Mars. We suggest that the most plausible models for secondary mineral formation involve the evaporation of low temperature o C) brines. This is consistent with the simple mineralogy of these assemblages -Fe-Mg-Ca carbonates, anhydrite, gypsum, halite, clays -and the chemical fractionation of Ca-to Mg-rich carbonate in ALH84001 'rosettes'. Longer-lived, and higher temperature, hydrothermal systems would have caused more silicate alteration than is seen and probably more complex mineral assemblages. Experimental and phase equilibria data on carbonate compositions similar to those present in the SNCs imply low temperatures of formation with cooling taking place over a short period of time (e.g. days). The ALH84001 carbonate also probably shows the effects of partial vapourisation and dehydration related to an impact event postdating the initial precipitation. This shock event may have led to the formation of sulphide and some magnetite in the Fe-rich outer parts of the rosettes.Radiometric dating (K-Ar, Rb-Sr) of the secondary mineral assemblages in one of the nakhlites (Lafayette) suggests that they formed between 0 and 670 Ma, and certainly long after the crystallisation of the host igneous rocks. Crystallisation of ALH84001 carbonate took place 0.5 Ga after the parent rock. These age ranges and the other research on these assemblages suggest that environmental conditions conducive to near-surface liquid water have been present on Mars periodically over the last ~1 Ga. This fluid activity cannot have been continuous over geological time because in that case much more silicate alteration would have taken place in the meteorite parent rocks and the soluble salts would probably not have been preserved.The secondary minerals could have been precipitated from brines with seawater-like composition, high bicarbonate contents and a weakly acidic nature. The co-existence of siderite (Fe-carbonate) and clays in the nakhlites suggests that the pCO 2 level in equilibrium with the parent brine may have been 50 mbar or more. The brines could have originated as flood waters which percolated through the top few hundred metres of the crust, releasing cations from the surrounding parent rocks. There is no spectroscopic or photographic evidence for extensive evaporite deposits on the current martian surface but some salt precipitation through solute concentration must have occurred as floodwaters associated with many of the martian channels ponded in low-lying areas. The high sulphur and chlorine concentrations of the martian soil have most likely resulted from aeolian redistribution of such aqueously-deposited salts and from reaction of the martian surface with volcanic acid volatiles. However, the SNC salt a...

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Section: Suggested Relic Biological Activity In Alh84001mentioning

confidence: 88%

Alteration Assemblages in Martian Meteorites: Implications for Near-Surface Processes

Bridges

Catling

Saxton

et al. 2001

Space Sciences Series of ISSI

128

201

View full text Add to dashboard Cite

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“…Meteorites are known to be colonized by the microorganisms (Steele et al 2000). The microbial consortia associated with the Tatahouine meteorite (classified as a diogenite [Lacroix 1931]) from the Sahara was found to be a subset of that found in the surrounding soil (Benzerara et al 2006), suggesting that the weathering populations within meteorites are distinct.…”

Section: Introductionmentioning

confidence: 99%

Laboratory experiments on the weathering of iron meteorites and carbonaceous chondrites by iron‐oxidizing bacteria

Gronstal

Pearson

Kappler³

et al. 2009

Meteorit & Planetary Scien

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Abstract-Batch culture experiments were performed to investigate the weathering of meteoritic material by iron-oxidizing bacteria. The aerobic, acidophilic iron oxidizer (A. ferrooxidans) was capable of oxidizing iron from both carbonaceous chondrites (Murchison and Cold Bokkeveld) and iron meteorites (York and Casas Grandes). Preliminary iron isotope results clearly show contrasted iron pathways during oxidation with and without bacteria suggesting that a biological role in meteorite weathering could be distinguished isotopically. Anaerobic iron-oxidizers growing under pH-neutral conditions oxidized iron from iron meteorites. These results show that rapid biologicallymediated alteration of extraterrestrial materials can occur in both aerobic and anaerobic environments. These results also demonstrate that iron can act as a source of energy for microorganisms from both iron and carbonaceous chondrites in aerobic and anaerobic conditions with implications for life on the early Earth and the possible use of microorganisms to extract minerals from asteroidal material.

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“…That interpretation is however very controversial (e.g. Steele et al 2000;Farquhar & Thiemens 2000).…”

Section: Introductionmentioning

confidence: 99%

Discovery of calcite in the solar type protostar NGC 1333-IRAS 4

Ceccarelli

Caux

Tielens

et al. 2002

A&A

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Abstract. We present observations, obtained with ISO-LWS, of the continuum between 50-200 µm of the solar type protostar IRAS 4, in the NGC 1333 complex. The continuum presents an excess, around 95 µm, that we demonstrate must be a dust feature. We compared the 95 µm excess with the calcite feature at 92 µm and find that it fits the observations reasonably well. There may be a further contribution from hydrous silicates at ∼100 µm, but this seems a less robust result. The detected calcite mass is ∼8 × 10 −5 M and represents about 1% of the warm (∼23 K) dust mass surrounding IRAS 4. This is only the second observation indicating the presence of carbonates outside the solar system, and the first revealing calcite in a young protostar. It is remarkable and intriguing that in all the objects where calcite has been detected so far, namely meteorites, planetary nebulae and IRAS 4, it represents from 0.3 to 1% of the dust mass. This new detection of calcite strengthens the claim by Kemper et al. (2002a) that calcite formation does not necessarely requires liquid water. We suggest that calcite forms at the surface of the grains, where water ice layers may locally have an enhanced mobility caused by heating due to hard X-rays emitted by the central object.

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Investigations into an unknown organism on the martian meteorite Allan Hills 84001

Cited by 55 publications

References 17 publications

Alteration Assemblages in Martian Meteorites: Implications for Near-Surface Processes

Alteration Assemblages in Martian Meteorites: Implications for Near-Surface Processes

Laboratory experiments on the weathering of iron meteorites and carbonaceous chondrites by iron‐oxidizing bacteria

Discovery of calcite in the solar type protostar NGC 1333-IRAS 4

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