Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001

  title={Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001},
  author={D. Mckay and E. Gibson and K. Thomas-Keprta and H. Vali and C. Romanek and S. Clemett and X. D. Chillier and C. R. Maechling and R. Zare},
  pages={924 - 930}
Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest that the PAHs are indigenous to the meteorite. High-resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globules show that the globules contain fine-grained, secondary phases of single-domain magnetite and iron… Expand
Modern terrestrial analogues for the carbonate globules in Martian meteorite ALH84001
Modern carbonate globules, located in cracks of submerged volcanic rocks and in calcareous pinnacles in alkaline (sodic) Lake Van, Turkey, appear to be analogues for the ~3.9 billion-year-old carbonates in Martian meteorite ALH84001, indicating that the ALH 84001 carbonates may have formed in similar setting on ancient Mars. Expand
An Evaporation Model for Formation of Carbonates in the ALH84001 Martian Meteorite
Small, discoid globules and networks of magnesium-iron-calcium carbonates occur within impact-produced fracture zones in the ALH84001 Martian meteorite. Because these carbonates contain or areExpand
Alteration Assemblages in Martian Meteorites: Implications for Near-Surface Processes
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 ∼1Expand
Petrography and bulk chemistry of Martian orthopyroxenite ALH84001: implications for the origin of secondary carbonates.
New petrologic and bulk geochemical data for the SNC-related (Martian) meteorite ALH84001 suggest a relatively simple igneous history overprinted by complex shock and hydrothermal processes, and petrographic textures are interpreted to be consistent with an inorganic origin for the carbonate involving dissolution-replacement reactions between CO2-charged fluids and feldspathic glass in the meteorite. Expand
Submicron magnetite grains and carbon compounds in Martian meteorite ALH84001: inorganic, abiotic formation by shock and thermal metamorphism.
  • A. Treiman
  • Materials Science, Medicine
  • Astrobiology
  • 2003
Purported biogenic features of the ALH84001 Martian meteorite (the carbonate globules, their submicron magnetite grains, and organic matter) have reasonable inorganic origins, and a comprehensiveExpand
The Search for Biosignatures in Martian Meteorite Allan Hills 84001
Proposed biosignatures in the ancient Allan Hills 84001 martian meteorite are most plausibly explained as abiotic features. The purported evidence of biological activity on Mars included biogenicExpand
Origin of carbonate-magnetite-sulfide assemblages in Martian meteorite ALH84001.
  • E. Scott
  • Geology, Medicine
  • Journal of geophysical research
  • 1999
It is proposed that carbonates originally formed in ALH84001 from aqueous fluids and were subsequently shock heated and vaporized, suggesting that the ALH 84001 carbonates have a unique origin. Expand
Paleomagnetic Evidence of a Low-Temperature Origin of Carbonate in the Martian Meteorite ALH84001
Study of two adjacent pyroxene grains from the crushed zone of ALH84001 shows that each possesses a stable natural remanent magnetization (NRM), implying that Mars had a substantial magnetic field when the grains cooled. Expand
[Meteoritics and mineralogy on possible ancient Martian life].
The mineralogical and biomineralogical evidence for martian bacteria given by McKay et al. (1996) is controversial, and could be formed by non-biogenic processes, so further study of ALH84001 and other martian meteorites is required. Expand
Graphite in the martian meteorite Allan Hills 84001
Abstract We use confocal Raman imaging spectroscopy and transmission electron microscopy to study the martian meteorite Allan Hills (ALH) 84001, reported to contain mineral assemblages withinExpand


A possible high-temperature origin for the carbonates in the martian meteorite ALH84001
It is argued that the most likely explanation for the observed compositions, and for the absence of co-existing hydrous minerals, is that the carbonates were formed by reactions between hot (>650 °C), CO2-rich fluids and the ultramafic host rock during an impact event. Expand
Soil mineralogy and chemistry on Mars - Possible clues from salts and clays in SNC meteorites
Abstract All subgroups of the shergottite, nakhlite, and chassignite (SNC) meteorites contain traces of water-precipitated minerals that include various combinations of carbonates, sulfates, halides,Expand
What we have learned about Mars from SNC meteorites
The SNC meteorites are thought to be igneous martian rocks, based on their young crystallization ages and a close match between the composition of gases implanted in them during shock and theExpand
Martian atmospheric carbon dioxide and weathering products in SNC meteorites
SNC meteorites—four shergottites, three nakhlites and Chassigny—are postulated to have originated on Mars1. Their late crystallization ages (<1,300 Myr compared with 4,600 Myr for other igneousExpand
Magnetofossil dissolution in a palaeomagnetically unstable deep-sea sediment
MAGNETOFOSSILS1, the fossil remains of bacterial magneto-somes2, are found in various deep-sea sediments, and have been linked to the preservation of stable natural remanent magnetization in many ofExpand
Ultrafine-grained magnetite in deep-sea sediments: Possible bacterial magnetofossils
A new extraction technique now permits ultrafine magnetite crystals to be separated from a variety of deep-sea sediments. Morphologic characterization of these particles with transmission electronExpand
Geochromatography on the parent body of the carbonaceous chondrite Ivuna
Abstract Ivuna, a CI carbonaceous chondrite, has been found to contain abundant amounts of the three-ring polycyclic aromatic hydrocarbons (PAHs) phenanthrene/anthracene, but no detectable levels ofExpand
ALH84001, a cumulate orthopyroxenite member of the martian meteorite clan
ALH84001, originally classified as a diogenite, is a coarse-grained, cataclastic, orthopyroxenite meteorite related to the martian (SNC) meteorites. The orthopyroxene is relatively uniform inExpand
Soft-bodied fossils from a Silurian volcaniclastic deposit
A group of soft-bodied fossils from carbonate concretions within a volcanic ash are described, identifying an important new source ofsoft-bodied taxa in the Silurian of Italy. Expand
Palaeomagnetic Applications in Hydrocarbon Exploration and Production
The main areas in which palaeomagnetic data may be useful to the petroleum geologist a,e : palaeomagnetic dating and magnetostratigraphy; susceptibility logging of cores; magnetic fabric studies forExpand