Experimental reproduction of the martian weathering profiles argues for a dense Noachian CO2 atmosphere

Viennet, Jean‐Christophe; Bultel, B.; Werner, Stéphanie C.

doi:10.1016/j.chemgeo.2019.07.009

Cited by 11 publications

(6 citation statements)

References 61 publications

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“…In contrast to results obtained in the absence of Mg-smectites, the final concentrations of C and N trapped within the solid residues were higher under CO2, even though the N/C values were slightly higher under N2/O2. Of note, an higher amount of residue is obtained under CO2, as a result of the lower dissolution rate of smectite under CO2 (Viennet et al, 2017(Viennet et al, , 2019b.…”

Section: Impact Of the Nature Of The Gas Phasementioning

confidence: 99%

Influence of the nature of the gas phase on the degradation of RNA during fossilization processes

Viennet

Bernard

Guillou

et al. 2020

Applied Clay Science

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Section: Impact Of the Nature Of The Gas Phasementioning

confidence: 99%

Influence of the nature of the gas phase on the degradation of RNA during fossilization processes

Viennet

Bernard

Guillou

et al. 2020

Applied Clay Science

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“…Under hydrothermal conditions, the dissolution of the Mg-smectites, together with the interlayer cationic exchange, releases Al, Mg and Ca in the system. Ca-carbonates then precipitate, the carbon source being either RNA degradation products (Sagemann et al, 1999) or the CO 2 rich atmosphere (Viennet et al, 2017(Viennet et al, , 2019. Meanwhile, the phosphate mono-ester groups of RNA underwent hydrolysis, leading to the precipitation of Al, Ca and Mg-phosphates ( Fig.…”

Section: Lettermentioning

confidence: 99%

Experimental clues for detecting biosignatures on Mars

Viennet¹,

Bernard²,

Guillou³

et al. 2019

Geochem. Persp. Let.

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Forthcoming exploration of Mars aims at identifying fossil biosignatures within ancient clay-rich formations. The subsurface of Mars has mostly acted as a giant freezer for the last 4 Gyr, thereby preserving potential remains of martian life. Yet, volcanism and impactors have periodically triggered the circulation of hydrothermal fluids, inevitably causing alteration of potentially fossilised biogenic organic materials. It thus appears crucial to quantify the impact of hydrothermal processes on organic biogeochemical signals in the presence of clay minerals. Here, we submitted RNA to hydrothermal conditions in the presence of Mg-smectites. Results show heterogeneous organo-mineral residues, with sub-micrometric phosphates, carbonates and amorphous silica particles together with Mg-smectites with interlayer spaces saturated by N-rich organic compounds. Although the chemical structure of RNA did not withstand hydrothermal conditions, clay minerals efficiently trapped organic carbon, confirming the relevance of drilling for organic carbon in ancient martian sediments. In addition, the degradation of RNA in the presence of Mg-smectites led to the precipitation of a quite uncommon mineral assemblage that could be seen as a biosignature per se. Martian targets exhibiting this mineral assemblage will thus constitute high priority and highly relevant candidates for sample return.

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“…Other studies have discovered the enrichment of Fe 3+ /Al 3+ -smectites in an acidic environment unnecessary to be in neutral or alkaline environments. 64,65 By contrast, Chevrier et al (2007) found that nontronite can be formed under a high oxidation level or weakly acidic to alkaline conditions. 66 In addition, considering the equilibrium between berthierine (berthierine is a Fe 2+ /Al-phyllosilicate) and nontronite, low aluminum activities are conducive to the precipitation of nontronite.…”

Section: Clay Minerals In Weatheringmentioning

confidence: 98%

Enigmatic Issues and Widening Implications of Research on Martian Clay Minerals

Zhong

Fiore

Chen

et al. 2022

ACS Earth Space Chem.

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Clay minerals are widespread in the Martian crust. Over the last few decades, accumulating data and research into the type, crystallinity, quantity, and distribution of Martian clay minerals (MCMs) has remarkably advanced the understanding of Martian geology, paleoclimate, environment, and the question of whether water, organic matter, and life exist there. Meanwhile, some issues remain enigmatic and arguable. To date, mineralogical data from orbiters and rovers have provided information regarding the distribution, composition, age, and geological evolution of MCMs. Several models for interpreting the formation of MCMs, including weathering, hydrothermal alteration, magmatic precipitation, and diagenesis, have been proposed. Nevertheless, the exact formation mechanism of MCM, remains unclear, primarily because of the lack of sufficient information on the chemical reactions and element cycles involved in the formation of clay minerals. Examination on the type, crystallinity, quantity, and distribution of MCMs indicates that Mars possibly had a warm and wet climate during the Noachian period. Since clay minerals possess abundant −OH groups in the layered structure and can host H 2 O in the interlayer space, MCMs are thought to be potentially large water reservoirs. Studies of MCMs and their interaction with organic matter are possibly conducive to finding answers to the question of whether or not on Mars life exists as clay minerals can preserve and enrich organic matter, catalyze the formation of biotic molecules, such as RNA oligomers, ribose, and amino acids, and even contribute to the assembly of vesicles. Future missions to Mars are recommended to set studies on MCMs with the key issues above and are expecting to lead to more exciting findings.

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Experimental reproduction of the martian weathering profiles argues for a dense Noachian CO2 atmosphere

Cited by 11 publications

References 61 publications

Influence of the nature of the gas phase on the degradation of RNA during fossilization processes

Influence of the nature of the gas phase on the degradation of RNA during fossilization processes

Experimental clues for detecting biosignatures on Mars

Enigmatic Issues and Widening Implications of Research on Martian Clay Minerals

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