Marta Ruiz-bermejo | National Institute of Aerospatial Technology (INTA) (original) (raw)
Papers by Marta Ruiz-bermejo
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan surface. We have used a high-energy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan's surface. We have used a highenergy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan's tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
Polymer Degradation and Stability, 2014
In order to further investigate the thermal characterization of hydrogen cyanide polymers, in thi... more In order to further investigate the thermal characterization of hydrogen cyanide polymers, in this study we focus on the thermogravimetry (TG) of three polymer samples obtained from different synthetic routes. The first one was synthesized from an aqueous solution of equimolar amounts of sodium cyanide (NH 4 Cl) and ammonium chloride (NaCN). The second one was produced from the polymerization of HCN gas in water, HCN being obtained from the reaction of NH 3 , CH 4 and air over a platinum catalyst at 1100 C; and the last sample was synthesized from anhydrous HCN, produced by the action of sulfuric acid on sodium cyanide. Differential thermal analysis (DTA), differential scanning calorimetry (DSC) and a coupled TG-mass spectrometer (MS) were used to evaluate the thermal behavior of these black polymers, which are of significant interest in prebiotic chemistry but also in extraterrestrial chemistry. All the samples present a similar thermal behavior. Following a dehydration process, three pyrolysis stages are observed, which occur over the temperature ranges of 150e300 C, 300e550 C and above 550 C. However, we observe that the char-forming reactions at higher temperatures, in the carbonization stage, is strongly dependent on the HCN polymer sample and the presence or absence of oxygen. During each stage, the same volatilization processes take place regardless of the type of HCN polymer sample. Deamination and dehydration reactions dominate in the low temperature range while thermal depolymerization, releasing HCN, and a denitrogenation process occur mainly at elevated temperatures. The release of isocyanic acid (or cyanic acid) and formamide are also identified within a wide range of temperatures. We discuss and interpret the thermal decomposition behavior to be related to the polymerization mechanisms in accordance with recent studies.
We investigate in laboratory on the fate of tholins once condensed into Titan's icy surface ... more We investigate in laboratory on the fate of tholins once condensed into Titan's icy surface and bombarded by meteoritic impacts and on the occurring organic chemistry. A pulsed laser has been used to ablate pure water ice with Titan tholins at 77 K.
Planetary and Space Science, 2013
Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and... more Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and presenting different degrees of exposure to ambient atmosphere have been used to study in detail their thermal behavior using thermogravimetry coupled with a mass spectrometer (TG-MS), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The degradation of Titan's tholins under inert atmosphere follows a three-step consecutive decomposition: a drying stage (4150 1C) where moisture is desorbed, this stage indicated the high hydrophilicity of the tholins; a second stage, the main pyrolysis stage (150-575 1C) where endothermic decomposition begins releasing mainly ammonia, HCN, acetonitrile, and methane over a broad temperature range. Few other hydrocarbon fragments such as ethylene and propane are released but no cyclic molecules, aliphatic or aromatic, are observed. The last stage (4 575 1C) is the carbonization of the material leading to a non-crystalline graphitic residue. The thermal degradation under oxygen atmosphere shows the same stages as in argon, with a shift of the thermogravimetric peaks toward lower temperatures indicating a lower thermal stability. The last stage in this case is an oxidative combustion of the char residue. This research concludes that even if Titan tholins, subjected to air contamination for few minutes to several years (varying with the storage conditions) transform to produce different C/N and C/O ratios and thermal stabilities, they undergo the same thermal degradation phases and products. This suggests that the studied three tholins have a similar main chemical structure which does not alter by the air exposure. We discuss on the possible nature of this structure.
Organic Geochemistry, 2016
Preservation windows of acidic environments are valuable tools to develop a strategy to search tr... more Preservation windows of acidic environments are valuable tools to develop a strategy to search traces of extinct life in materials originated during the Noachian on Mars. We show different preservation windows recognized in the Rio Tinto Mars analog.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 21, 2015
The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partia... more The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partially, tested experimentally. The prebiotic synthesis of cofactors or coenzymes is a poorly explored issue, likely because their formation under plausible prebiotic conditions is not clear. In this sense, it has been proposed that the cofactors are "molecular fossils" of an early phase of life. In contrast, Eschenmoser and Loewenthal suggested a prebiotic hydrocyanic origin of cofactor building blocks. In the present paper, the formation of a set of pterins from cyanide polymerizations is demonstrated, showing that the main structure of some cofactors can be prebiotically formed. Indeed, it was observed that aqueous aerosols additionally increase the relative composition for pterins in the insoluble NH4 CN polymers synthesized. The novel identification of pterins in NH4 CN polymers, together with the previous detection of other important biomonomers, indicates that cyanide polyme...
Chemistry - A European Journal, 2015
The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partia... more The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partially, tested experimentally. The prebiotic synthesis of cofactors or coenzymes is a poorly explored issue, likely because their formation under plausible prebiotic conditions is not clear. In this sense, it has been proposed that the cofactors are "molecular fossils" of an early phase of life. In contrast, Eschenmoser and Loewenthal suggested a prebiotic hydrocyanic origin of cofactor building blocks. In the present paper, the formation of a set of pterins from cyanide polymerizations is demonstrated, showing that the main structure of some cofactors can be prebiotically formed. Indeed, it was observed that aqueous aerosols additionally increase the relative composition for pterins in the insoluble NH4 CN polymers synthesized. The novel identification of pterins in NH4 CN polymers, together with the previous detection of other important biomonomers, indicates that cyanide polymerizations were essential in the early state of prebiotic chemistry.
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan's surface. We have used a highenergy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan's tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
In the whole Universe it is possible to find organic complex substances known with the generic na... more In the whole Universe it is possible to find organic complex substances known with the generic name of tholins. These substances are obtained by irradiation of several gas mixtures (excluding the O2). The analysis of the tholins indicates that they can release important bio organics present in proteins, nucleic-acid bases and so on. It has been proposed that the tholins
Planetary and Space Science, 2013
Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and... more Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and presenting different degrees of exposure to ambient atmosphere have been used to study in detail their thermal behavior using thermogravimetry coupled with a mass spectrometer (TG-MS), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The degradation of Titan's tholins under inert atmosphere follows a three-step consecutive decomposition: a drying stage (4150 1C) where moisture is desorbed, this stage indicated the high hydrophilicity of the tholins; a second stage, the main pyrolysis stage (150-575 1C) where endothermic decomposition begins releasing mainly ammonia, HCN, acetonitrile, and methane over a broad temperature range. Few other hydrocarbon fragments such as ethylene and propane are released but no cyclic molecules, aliphatic or aromatic, are observed. The last stage (4 575 1C) is the carbonization of the material leading to a non-crystalline graphitic residue. The thermal degradation under oxygen atmosphere shows the same stages as in argon, with a shift of the thermogravimetric peaks toward lower temperatures indicating a lower thermal stability. The last stage in this case is an oxidative combustion of the char residue. This research concludes that even if Titan tholins, subjected to air contamination for few minutes to several years (varying with the storage conditions) transform to produce different C/N and C/O ratios and thermal stabilities, they undergo the same thermal degradation phases and products. This suggests that the studied three tholins have a similar main chemical structure which does not alter by the air exposure. We discuss on the possible nature of this structure.
Journal of Environmental Monitoring, 2008
Geochimica et Cosmochimica Acta, 2006
Progressive weathering of rocks results in significant element fractionation in the Earth's regol... more Progressive weathering of rocks results in significant element fractionation in the Earth's regolith zone. This is most obvious and important in areas, including much of Australia, where weathering has been intense/prolonged and profiles well-preserved. The principle chemical processes include replacement of more soluble ions by protons and oxidation of some elements. Major element changes reflect the path from the primary mineral assemblage to the typical end products of quartz, kaolinite and hematite/goethite (i.e. variable loss of mainly K + , Na + Ca 2+ Mg 2+ and accumulation of Si 3+ , Al 3+ and Fe 3+ ). Minor and trace element fractionation reflects the relative retention or dispersion from the primary host minerals (depending on their stability) and sequestration of released elements by specific secondary host minerals.
Geochmica et Cosmochimica Acta
The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconfo... more The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconformable contact between Namurian black limestones and dolostones and red beds of Triassic age. These MVT-like deposits replace the dolomitized limestones of the basement, 2-4 m thick of an scarp-related carbonate-rich red breccia (La Riera conglomerate, product of the erosion of the underlying limestones) and the Muschelkalk dolostones (3 m thick) located below the red marly shales; these red beds only show a minor replacement. Some nearby mineralized vertical NNW-SSE trending faults of late-to postvariscan age are interpreted as the feeder zones of these manto deposits. The fluorite is associated with quartz, barite, calcite and minor sulphides. A significant feature is the presence of abundant solid organic matter as cm-sized pods interstitial of the hydrothermal minerals or as solid and fluid inclusions in the quartz and fluorite.
Chemistry - A European Journal
Herein, we report the efficient synthesis of RNA bases and functionalized s-triazines from 0.1m u... more Herein, we report the efficient synthesis of RNA bases and functionalized s-triazines from 0.1m urea solutions in water after subjection to freeze–thaw cycles for three weeks. The icy solution was under a reductive, methane-based atmosphere, which was subjected to spark discharges as an energy source for the first 72 h of the experiment. Analysis of the products indicates the synthesis of the s-triazines cyanuric acid, ammeline, ammelide, and melamine, the pyrimidines cytosine, uracil, and 2,4-diaminopyrimidine, and the purine adenine. An experiment performed as a control at room temperature, with the urea solution in the liquid phase and with the same atmosphere and energy source, led to the synthesis of hydantoins and insoluble tholin, but there was no evidence of the synthesis of pyrimidines or triazines. The synthesis of pyrimidines from urea is possible under a methane/nitrogen atmosphere only at low temperature, in the solid phase. The generation of both pyrimidines and triazi...
Geochmica et Cosmochimica Acta
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan surface. We have used a high-energy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconfo... more The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconformable contact between Namurian black limestones and dolostones and red beds of Triassic age. These MVT-like deposits replace the dolomitized limestones of the basement, 2-4 m thick of an scarp-related carbonate-rich red breccia (La Riera conglomerate, product of the erosion of the underlying limestones) and the Muschelkalk dolostones (3 m thick) located below the red marly shales; these red beds only show a minor replacement. Some nearby mineralized vertical NNW-SSE trending faults of late-to postvariscan age are interpreted as the feeder zones of these manto deposits. The fluorite is associated with quartz, barite, calcite and minor sulphides. A significant feature is the presence of abundant solid organic matter as cm-sized pods interstitial of the hydrothermal minerals or as solid and fluid inclusions in the quartz and fluorite.
The restrictions imposed by instrumentation and some methodological constraints make that only vo... more The restrictions imposed by instrumentation and some methodological constraints make that only volatile organic compounds have been analyzed by in situ instruments in planetary exploration. It has been argued that polycarboxilic acids like the hexacarboxylic acid (mellitic acid) can be produced and accumulated in the martian regolith from the oxidation of meteoritic organic matter. However, these compounds are non-volatile and instruments designed for the analysis of volatile compounds would not detect them. Herein we report the production of an antibody to mellitic acid and the development of a fluorescent inhibition microarray immunoassay (IMI) to detect this substance to a limit of 5 ppb (ng mL À1 ). We used the anti-mellitic antibody to detect mellitic acid in drill core samples obtained from different depths in the Atacama desert (Chile), a highly relevant terrestrial analogue for Mars. The presence of mellitic acid was corroborated by organic extraction and GC/MS analysis. Our results showed a smooth gradient of mellitic acid concentration, being higher at the surface and near the surface (1.17-1.57 ppm) and diminishing with depth to be undetectable at a depth of 4 m. Our immunoassay can be easily implemented in instruments for in situ analysis.
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan surface. We have used a high-energy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan's surface. We have used a highenergy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan's tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
Polymer Degradation and Stability, 2014
In order to further investigate the thermal characterization of hydrogen cyanide polymers, in thi... more In order to further investigate the thermal characterization of hydrogen cyanide polymers, in this study we focus on the thermogravimetry (TG) of three polymer samples obtained from different synthetic routes. The first one was synthesized from an aqueous solution of equimolar amounts of sodium cyanide (NH 4 Cl) and ammonium chloride (NaCN). The second one was produced from the polymerization of HCN gas in water, HCN being obtained from the reaction of NH 3 , CH 4 and air over a platinum catalyst at 1100 C; and the last sample was synthesized from anhydrous HCN, produced by the action of sulfuric acid on sodium cyanide. Differential thermal analysis (DTA), differential scanning calorimetry (DSC) and a coupled TG-mass spectrometer (MS) were used to evaluate the thermal behavior of these black polymers, which are of significant interest in prebiotic chemistry but also in extraterrestrial chemistry. All the samples present a similar thermal behavior. Following a dehydration process, three pyrolysis stages are observed, which occur over the temperature ranges of 150e300 C, 300e550 C and above 550 C. However, we observe that the char-forming reactions at higher temperatures, in the carbonization stage, is strongly dependent on the HCN polymer sample and the presence or absence of oxygen. During each stage, the same volatilization processes take place regardless of the type of HCN polymer sample. Deamination and dehydration reactions dominate in the low temperature range while thermal depolymerization, releasing HCN, and a denitrogenation process occur mainly at elevated temperatures. The release of isocyanic acid (or cyanic acid) and formamide are also identified within a wide range of temperatures. We discuss and interpret the thermal decomposition behavior to be related to the polymerization mechanisms in accordance with recent studies.
We investigate in laboratory on the fate of tholins once condensed into Titan's icy surface ... more We investigate in laboratory on the fate of tholins once condensed into Titan's icy surface and bombarded by meteoritic impacts and on the occurring organic chemistry. A pulsed laser has been used to ablate pure water ice with Titan tholins at 77 K.
Planetary and Space Science, 2013
Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and... more Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and presenting different degrees of exposure to ambient atmosphere have been used to study in detail their thermal behavior using thermogravimetry coupled with a mass spectrometer (TG-MS), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The degradation of Titan's tholins under inert atmosphere follows a three-step consecutive decomposition: a drying stage (4150 1C) where moisture is desorbed, this stage indicated the high hydrophilicity of the tholins; a second stage, the main pyrolysis stage (150-575 1C) where endothermic decomposition begins releasing mainly ammonia, HCN, acetonitrile, and methane over a broad temperature range. Few other hydrocarbon fragments such as ethylene and propane are released but no cyclic molecules, aliphatic or aromatic, are observed. The last stage (4 575 1C) is the carbonization of the material leading to a non-crystalline graphitic residue. The thermal degradation under oxygen atmosphere shows the same stages as in argon, with a shift of the thermogravimetric peaks toward lower temperatures indicating a lower thermal stability. The last stage in this case is an oxidative combustion of the char residue. This research concludes that even if Titan tholins, subjected to air contamination for few minutes to several years (varying with the storage conditions) transform to produce different C/N and C/O ratios and thermal stabilities, they undergo the same thermal degradation phases and products. This suggests that the studied three tholins have a similar main chemical structure which does not alter by the air exposure. We discuss on the possible nature of this structure.
Organic Geochemistry, 2016
Preservation windows of acidic environments are valuable tools to develop a strategy to search tr... more Preservation windows of acidic environments are valuable tools to develop a strategy to search traces of extinct life in materials originated during the Noachian on Mars. We show different preservation windows recognized in the Rio Tinto Mars analog.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 21, 2015
The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partia... more The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partially, tested experimentally. The prebiotic synthesis of cofactors or coenzymes is a poorly explored issue, likely because their formation under plausible prebiotic conditions is not clear. In this sense, it has been proposed that the cofactors are "molecular fossils" of an early phase of life. In contrast, Eschenmoser and Loewenthal suggested a prebiotic hydrocyanic origin of cofactor building blocks. In the present paper, the formation of a set of pterins from cyanide polymerizations is demonstrated, showing that the main structure of some cofactors can be prebiotically formed. Indeed, it was observed that aqueous aerosols additionally increase the relative composition for pterins in the insoluble NH4 CN polymers synthesized. The novel identification of pterins in NH4 CN polymers, together with the previous detection of other important biomonomers, indicates that cyanide polyme...
Chemistry - A European Journal, 2015
The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partia... more The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partially, tested experimentally. The prebiotic synthesis of cofactors or coenzymes is a poorly explored issue, likely because their formation under plausible prebiotic conditions is not clear. In this sense, it has been proposed that the cofactors are "molecular fossils" of an early phase of life. In contrast, Eschenmoser and Loewenthal suggested a prebiotic hydrocyanic origin of cofactor building blocks. In the present paper, the formation of a set of pterins from cyanide polymerizations is demonstrated, showing that the main structure of some cofactors can be prebiotically formed. Indeed, it was observed that aqueous aerosols additionally increase the relative composition for pterins in the insoluble NH4 CN polymers synthesized. The novel identification of pterins in NH4 CN polymers, together with the previous detection of other important biomonomers, indicates that cyanide polymerizations were essential in the early state of prebiotic chemistry.
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan's surface. We have used a highenergy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan's tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
In the whole Universe it is possible to find organic complex substances known with the generic na... more In the whole Universe it is possible to find organic complex substances known with the generic name of tholins. These substances are obtained by irradiation of several gas mixtures (excluding the O2). The analysis of the tholins indicates that they can release important bio organics present in proteins, nucleic-acid bases and so on. It has been proposed that the tholins
Planetary and Space Science, 2013
Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and... more Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and presenting different degrees of exposure to ambient atmosphere have been used to study in detail their thermal behavior using thermogravimetry coupled with a mass spectrometer (TG-MS), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The degradation of Titan's tholins under inert atmosphere follows a three-step consecutive decomposition: a drying stage (4150 1C) where moisture is desorbed, this stage indicated the high hydrophilicity of the tholins; a second stage, the main pyrolysis stage (150-575 1C) where endothermic decomposition begins releasing mainly ammonia, HCN, acetonitrile, and methane over a broad temperature range. Few other hydrocarbon fragments such as ethylene and propane are released but no cyclic molecules, aliphatic or aromatic, are observed. The last stage (4 575 1C) is the carbonization of the material leading to a non-crystalline graphitic residue. The thermal degradation under oxygen atmosphere shows the same stages as in argon, with a shift of the thermogravimetric peaks toward lower temperatures indicating a lower thermal stability. The last stage in this case is an oxidative combustion of the char residue. This research concludes that even if Titan tholins, subjected to air contamination for few minutes to several years (varying with the storage conditions) transform to produce different C/N and C/O ratios and thermal stabilities, they undergo the same thermal degradation phases and products. This suggests that the studied three tholins have a similar main chemical structure which does not alter by the air exposure. We discuss on the possible nature of this structure.
Journal of Environmental Monitoring, 2008
Geochimica et Cosmochimica Acta, 2006
Progressive weathering of rocks results in significant element fractionation in the Earth's regol... more Progressive weathering of rocks results in significant element fractionation in the Earth's regolith zone. This is most obvious and important in areas, including much of Australia, where weathering has been intense/prolonged and profiles well-preserved. The principle chemical processes include replacement of more soluble ions by protons and oxidation of some elements. Major element changes reflect the path from the primary mineral assemblage to the typical end products of quartz, kaolinite and hematite/goethite (i.e. variable loss of mainly K + , Na + Ca 2+ Mg 2+ and accumulation of Si 3+ , Al 3+ and Fe 3+ ). Minor and trace element fractionation reflects the relative retention or dispersion from the primary host minerals (depending on their stability) and sequestration of released elements by specific secondary host minerals.
Geochmica et Cosmochimica Acta
The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconfo... more The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconformable contact between Namurian black limestones and dolostones and red beds of Triassic age. These MVT-like deposits replace the dolomitized limestones of the basement, 2-4 m thick of an scarp-related carbonate-rich red breccia (La Riera conglomerate, product of the erosion of the underlying limestones) and the Muschelkalk dolostones (3 m thick) located below the red marly shales; these red beds only show a minor replacement. Some nearby mineralized vertical NNW-SSE trending faults of late-to postvariscan age are interpreted as the feeder zones of these manto deposits. The fluorite is associated with quartz, barite, calcite and minor sulphides. A significant feature is the presence of abundant solid organic matter as cm-sized pods interstitial of the hydrothermal minerals or as solid and fluid inclusions in the quartz and fluorite.
Chemistry - A European Journal
Herein, we report the efficient synthesis of RNA bases and functionalized s-triazines from 0.1m u... more Herein, we report the efficient synthesis of RNA bases and functionalized s-triazines from 0.1m urea solutions in water after subjection to freeze–thaw cycles for three weeks. The icy solution was under a reductive, methane-based atmosphere, which was subjected to spark discharges as an energy source for the first 72 h of the experiment. Analysis of the products indicates the synthesis of the s-triazines cyanuric acid, ammeline, ammelide, and melamine, the pyrimidines cytosine, uracil, and 2,4-diaminopyrimidine, and the purine adenine. An experiment performed as a control at room temperature, with the urea solution in the liquid phase and with the same atmosphere and energy source, led to the synthesis of hydantoins and insoluble tholin, but there was no evidence of the synthesis of pyrimidines or triazines. The synthesis of pyrimidines from urea is possible under a methane/nitrogen atmosphere only at low temperature, in the solid phase. The generation of both pyrimidines and triazi...
Geochmica et Cosmochimica Acta
We present results of laboratory experiments carried out to examine the impact-induced chemistry ... more We present results of laboratory experiments carried out to examine the impact-induced chemistry on Titan and to study the reactivity and a possible fate of tholins on Titan surface. We have used a high-energy pulsed laser to recreate the energetic processes during meteoritic impacts shocks. The experiments have consisted in ablating pure water ices and ices of 15% NH4OH in water containing Titan tholins at 77 K under vacuum. We have examined optically the chemical changes of impacted tholins and studied the formation of complex organic compounds in the impacted ices.
The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconfo... more The fluorite deposits of the Berbes area occur as stratabound orebodies located along the unconformable contact between Namurian black limestones and dolostones and red beds of Triassic age. These MVT-like deposits replace the dolomitized limestones of the basement, 2-4 m thick of an scarp-related carbonate-rich red breccia (La Riera conglomerate, product of the erosion of the underlying limestones) and the Muschelkalk dolostones (3 m thick) located below the red marly shales; these red beds only show a minor replacement. Some nearby mineralized vertical NNW-SSE trending faults of late-to postvariscan age are interpreted as the feeder zones of these manto deposits. The fluorite is associated with quartz, barite, calcite and minor sulphides. A significant feature is the presence of abundant solid organic matter as cm-sized pods interstitial of the hydrothermal minerals or as solid and fluid inclusions in the quartz and fluorite.
The restrictions imposed by instrumentation and some methodological constraints make that only vo... more The restrictions imposed by instrumentation and some methodological constraints make that only volatile organic compounds have been analyzed by in situ instruments in planetary exploration. It has been argued that polycarboxilic acids like the hexacarboxylic acid (mellitic acid) can be produced and accumulated in the martian regolith from the oxidation of meteoritic organic matter. However, these compounds are non-volatile and instruments designed for the analysis of volatile compounds would not detect them. Herein we report the production of an antibody to mellitic acid and the development of a fluorescent inhibition microarray immunoassay (IMI) to detect this substance to a limit of 5 ppb (ng mL À1 ). We used the anti-mellitic antibody to detect mellitic acid in drill core samples obtained from different depths in the Atacama desert (Chile), a highly relevant terrestrial analogue for Mars. The presence of mellitic acid was corroborated by organic extraction and GC/MS analysis. Our results showed a smooth gradient of mellitic acid concentration, being higher at the surface and near the surface (1.17-1.57 ppm) and diminishing with depth to be undetectable at a depth of 4 m. Our immunoassay can be easily implemented in instruments for in situ analysis.