Microbialites vs detrital micrites: Degree of biogenicity, parameter suitable for Mars analogues

Blanco, A.; D’Elia, M.; Orofino, V.; Mancarella, F.; Fonti, S.; Mastandrea, Adelaide; Guido, Adriano; Tosti, Fabio; Russo, Federico

doi:10.1016/j.pss.2014.04.005

Cited by 7 publications

(9 citation statements)

References 66 publications

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“…The organic-induced nature of microbialite was supposed on the base of micromorphological and biogeochemical evidence (Russo et al 1997;Tosti et al 2011Tosti et al , 2012Tosti et al , 2014. Their biotic origin has been confirmed by Blanco et al (2013Blanco et al ( , 2014 with independent methods.…”

Section: Sample Description and Preparationmentioning

confidence: 99%

“…The method has been then successfully applied to bio-induced carbonates deposit, i.e. microbialites (Blanco et al 2011, 2013), and very recently, by studying different parts of the same rock sample, we have been able to discriminate the different origin of the fine carbonate fractions, namely the micrite types (Blanco et al 2014). The term micrite, introduced by Folk (1959), is the abbreviation of ‘microcrystalline calcite’ and is commonly used to describe the particles <4 µm in size (Tucker & Wright 1990).…”

Section: Introductionmentioning

confidence: 99%

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SEM morphological studies of carbonates and the search for ancient life on Mars

D’Elia

Blanco

Galiano

et al. 2016

International Journal of Astrobiology

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Next space missions will investigate the possibility of extinct or extant life on Mars. Studying the infrared spectral modifications, induced by thermal processing on different carbonate samples (recent shells and fossils of different ages), we developed a method able to discriminate biogenic carbonates from their abiogenic counterparts. The method has been successfully applied to microbialites, i.e. bio-induced carbonates deposits, and particularly to stromatolites, the laminated fabric of microbialites, some of which can be ascribed to among the oldest traces of biological activity known on Earth. These results are of valuable importance since such carbonates are linked to primitive living organisms that can be considered as good analogues for putative Martian life forms. Considering that the microstructures of biogenic carbonate are different from those of abiogenic origin, we investigated the micromorphology of shells, skeletal grains and microbialites at different scale with a scanning electron microscope. The results show that this line of research may provide an alternative and complementary approach to other techniques developed in the past by our group to distinguish biotic from abiotic carbonates. In this paper, we present some results that can be of valuable interest since they demonstrate the utility for a database of images concerning the structures and textures of relevant carbonate minerals. Such data may be useful for the analysis of Martian samples, coming from sample return missions or investigated by future in situ explorations, aimed to characterize the near-subsurface of Mars in search for past or present life.

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Section: Sample Description and Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SEM morphological studies of carbonates and the search for ancient life on Mars

D’Elia

Blanco

Galiano

et al. 2016

International Journal of Astrobiology

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“…In the past, different experimental techniques such as IR spectroscopy, gravimetry, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis have been used to investigate spectral, morphological, and compositional modifications induced by thermal processing on different samples [38][39][40][41][42]. The goal was to develop a method able to discriminate biogenic carbonate samples from their abiogenic counterparts, to determine the degree of biogenicity of different samples.…”

Section: Theory and Experiment: Calcite Decompositionmentioning

confidence: 99%

“…• problematic carbonate samples, in which there is no clear evidence of controlled or induced biomineralization [40]; • microbialites, i.e., bio-induced carbonate deposits, and stromatolites, i.e., the laminated fabric of microbialites, some of which are among the most primitive traces of biological activity on Earth [41]; • different parts of the same carbonate rock to discriminate the presence, nature and degree of biogenicity of various micrite types (i.e., detrital vs autochthonous) and to distinguish them from the skeletal grains, each one characterized by different organic matter content [42].…”

Section: Theory and Experiment: Calcite Decompositionmentioning

confidence: 99%

“…In the past, the thermal decomposition of WSMs has found other applications in the context of astrobiology. For example, laboratory studies have demonstrated that if calcite (of biotic or abiotic origin) is subjected to thermal process at moderate temperature (485 • C), the resulting partial decomposition of this carbonate, evaluated by IR spectroscopy, may provide precious information about its degree of biogenicity [38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of White Soft Minerals (WSMs) Decomposition under Conditions of Interest for Astrobiology: A Theoretical and Experimental Study

et al. 2019

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In this paper, the thermal decomposition kinetics of a class of minerals that we call White Soft Minerals (WSMs) is studied by means of theoretical and experimental methods, in connection to the transport of extraterrestrial organic matter to Earth and the possible use of the decomposition reaction in the characterization of these minerals in space. WSMs include, under a single denomination, carbonates and sulphates of Mg, Fe, and Ca. To improve the present knowledge of the properties of such materials, we use the following techniques: kinetic models for chemical decomposition, atmospheric entry models, spectroscopy, and gravimetric analyses. Model results show that the atmospheric entry of WSM grains is strongly affected by their thermal decomposition. The decomposition reaction, being strongly endothermic, tends to significantly lower the grain temperature during the atmospheric entry, especially at high altitudes and for grazing entries. A previously proposed infrared spectroscopic technique to evaluate the degree of advancement of the reaction is found to be in good agreement with gravimetric measurements for calcium carbonate. The numerical model developed for the atmospheric entry scenarios is used to interpret experimental results. These main findings show that an additional contribution to the reaction enthalpy is needed to reproduce the experimental results, suggesting that the present theoretical model needs improvements such as the account of gas diffusion in the materials.

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Micrometeoroids as Carriers of Organics: Modeling of the Atmospheric Entry and Chemical Decomposition of Sub‐Millimeter Grains

Longo

2021

Planet Formation and Panspermia

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Microbialites vs detrital micrites: Degree of biogenicity, parameter suitable for Mars analogues

Cited by 7 publications

References 66 publications

SEM morphological studies of carbonates and the search for ancient life on Mars

SEM morphological studies of carbonates and the search for ancient life on Mars

Kinetics of White Soft Minerals (WSMs) Decomposition under Conditions of Interest for Astrobiology: A Theoretical and Experimental Study

Micrometeoroids as Carriers of Organics: Modeling of the Atmospheric Entry and Chemical Decomposition of Sub‐Millimeter Grains

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