Extra terrestrial abiogenic organization of organic matter: The hollow spheres of the Orgueil meteorite

Rossignol-Strick, Martine; Barghoorn, Elso S.

doi:10.1007/bf00927984

Cited by 27 publications

(13 citation statements)

References 80 publications

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“…It is now widely accepted that the "organized elements" found in the carbonaceous meteorites by Claus and Nagy 3-6 and others [7][8][9][10][11][12] was either the result of intentional contamination 13 of the meteorites or of contamination by recent pollen grains [14][15][16][17][18] even though this conclusion was clearly shown to be incorrect by studies carried out many years ago by well known micropaleontologists and palynologists. 20 The acid maceration methodologies used in many of these early studies to search for acid-resistant microfossils would not have destroyed the pollen contaminants that might have been present on external surfaces of old fractures within the fusion crust. Unfortunately, one of the original Claus and Nagy 1 images was of a contaminant pollen grain and this contributed heavily to the ensuing debate.…”

Section: Contamination Control Protocol and Methodologymentioning

confidence: 99%

Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

Hoover

2005

Astrobiology and Planetary Missions

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The quest for conclusive evidence of microfossils in meteorites has been elusive. Abiotic microstructures, mineral grains, and even coating artifacts may mimic unicellular bacteria, archaea and nanobacteria with simple spherical or rod morphologies (i.e., cocci, diplococci, bacilli, etc.). This is not the case for the larger and more complex microorganisms, colonies and microbial consortia and ecosystems. Microfossils of algae, cyanobacteria, and cyanobacterial and microbial mats have been recognized and described from many of the most ancient rocks on Earth. The filamentous cyanobacteria and sulphur-bacteria have very distinctive size ranges, complex and recognizable morphologies and visibly differentiated cellular microstructures. The taphonomic modes of fossilization and the life habits and processes of these microorganisms often result in distinctive chemical biosignatures associated with carbonization, silicification, calcification, phosphatization and metal-binding properties of their cell-walls, trichomes, sheaths and extracellular polymeric substances (EPS). Valid biogenicity is provided by the combination of a suite of known biogenic elements (that differ from the meteorite matrix) found in direct association with recognizable and distinct biological features and microstructures (e.g., uniseriate or multiseriate filaments, trichomes, sheaths and cells of proper size/size range); specialized cells (e.g., basal or apical cells, hormogonia, akinetes, and heterocysts); and evidence of growth characteristics (e.g., spiral filaments, robust or thin sheaths, laminated sheaths, true or false branching of trichomes, tapered or uniform filaments) and evidence of locomotion (e.g. emergent cells and trichomes, coiling hormogonia, and hollow or flattened and twisted sheaths).Since 1997 we have conducted Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) studies of freshly fractured interior surfaces of carbonaceous meteorites, terrestrial rocks, living, cryopreserved and fossilized extremophiles and cyanobacteria. These studies have resulted in the detection of mineralized remains of morphotypes of filamentous cyanobacteria, mats and consortia in many carbonaceous meteorites. These well-preserved and embedded microfossils are consistent with the size, morphology and ultramicrostructure of filamentous trichomic prokaryotes and degraded remains of microfibrils of cyanobacterial sheaths. EDAX elemental studies reveal that the forms in the meteorites often have highly carbonized sheaths in close association with permineralized filaments, trichomes, and microbial cells. The eextensive protocols and methodologies that have been developed to protect the samples from contamination and to distinguish recent contaminants from indigenous microfossils are described recent bio-contaminants. Ratios of critical bioelements (C:O, C:N, C:P, and C:S) reveal dramatic differences between microfossils in Earth rocks and meteorites and in the cells, filaments, trichomes, and hormogonia of recently living cyanob...

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Section: Contamination Control Protocol and Methodologymentioning

confidence: 99%

Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

Hoover

2005

Astrobiology and Planetary Missions

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“…If the self-assembly of amphiphilic molecules into membranes preceded the origin of life, it is plausible that the earliest living systems may have had access to encapsulated environments. Over the past 40 years there have been numerous reports of rounded, sometimes hollow, prebiotic hydrocarbon objects (namely membranes) in carbonaceous chondrites (Claus & Nagy 1961;Fitch et al 1962;Nagy et al 1963;Rossignol-Strick & Barghoorn 1971;Alpern & Benkheiri 1973;Pflug 1984;Steele et al 2000). These reports, however, have been viewed with much scepticism by most workers for one or more of the following reasons :…”

Section: History Of Prebiotic Signatures In Meteoritesmentioning

confidence: 99%

“…(1) the organic structures were found only after acid digestions or other aqueous processing, which could have significantly modified the hydrocarbon chemistry and the structures present (Claus & Nagy 1961 ;Nagy et al 1963;Rossignol-Strick & Barghoorn 1971 ;Pflug 1984) ; (2) poorly documented or improper precautions were taken to eliminate contamination by terrestrial materials (Pflug 1984) ;…”

Section: History Of Prebiotic Signatures In Meteoritesmentioning

confidence: 99%

Hollow organic globules in the Tagish Lake meteorite as possible products of primitive organic reactions

Nakamura

Zolensky

Tomita

et al. 2002

International Journal of Astrobiology

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We report the first in situ observation of hollow organic globules in any extraterrestrial material using the Tagish Lake carbonaceous chondrite. Data from analytical transmission electron microscopy, Raman and micro-Fourier-transform infrared (FTIR) spectroscopy indicate that the globules consist of aliphatic and oxygenated functions. The hollow spherical morphologies are strikingly similar to the material produced by the laboratory simulation of ultraviolet photolysis of interstellar ice analogues and subsequent aqueous processing, suggesting that the organic globules in the Tagish Lake meteorite may be extremely primitive organic material that formed before or during the formation of the solar system. The FTIR organic signatures also show strong similarities to the membrane-like products formed from hydrothermal reaction of an OH-bearing amino acid in the presence of hydrous minerals. The survival of the structures in the Tagish Lake sample indicates that primitive meteorites must have delivered these structures to the early Earth as a possible precursor to life.

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“…Acid-resistant, organic, hollow-walled forms extracted from Orgueil were considered to be organic-walled forms indigenous to Orgueil that were definitively not pollen and could not be dismissed as recent contaminants. 35,36 Orgueil has also been found to contain a number of acritarch-like forms similar to fossil Acritarchs with single pylome and processes described as Leiosphaeridia epikoila by Zang and Walter 37 from the Bitter Springs Formation of Australia. [Acritarchs are spherical, organic-walled microfossils of uncertain affinities that first appeared in the fossil record in 1.8 billion year old rocks, most likely belonging to ancient groups of planktonic eukaryotic algae.…”

Section: Orgueil Meteoritementioning

confidence: 99%

Fossil signatures using elemental abundance distributions and Bayesian probabilistic classification

Storrie-Lombardi¹,

Hoover

2004

Instruments, Methods, and Missions for Astrobiology VIII

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Mn 25 , Fe 26 , and Ni 28 ) were obtained for a set of terrestrial fossils and the rock matrix surrounding them. Principal Component Analysis extracted five factors accounting for the 92.5% of the data variance, i.e. information content, of the elemental abundance data. Hierarchical Cluster Analysis provided unsupervised sample classification distinguishing fossil from matrix samples on the basis of either raw abundances or PCA input that agreed strongly with visual classification. A stochastic, non-linear Artificial Neural Network produced a Bayesian probability of correct sample classification. The results provide a quantitative probabilistic methodology for discriminating terrestrial fossils from the surrounding rock matrix using chemical information. To demonstrate the applicability of these techniques to the assessment of meteoritic samples or in situ extraterrestrial exploration, we present preliminary data on samples of the Orgueil meteorite. In both systems an elemental signature produces target classification decisions remarkably consistent with morphological classification by a human expert using only structural (visual) information. We discuss the possibility of implementing a complexity analysis metric capable of automating certain image analysis and pattern recognition abilities of the human eye using low magnification optical microscopy images and discuss the extension of this technique across multiple scales.

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Extra terrestrial abiogenic organization of organic matter: The hollow spheres of the Orgueil meteorite

Cited by 27 publications

References 80 publications

Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

Hollow organic globules in the Tagish Lake meteorite as possible products of primitive organic reactions

Fossil signatures using elemental abundance distributions and Bayesian probabilistic classification

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