CO2 In Martian Atmosphere Research Articles

Evaluation of low-pressure mechanical compression for Martian atmospheric CO2 capture: Implications for in-situ resource utilization

Evaluation of low-pressure mechanical compression for Martian atmospheric CO2 capture: Implications for in-situ resource utilization

NanoSIMS analysis of organic carbon from the Tissint Martian meteorite: Evidence for the past existence of subsurface organic‐bearing fluids on Mars

AbstractTwo petrographic settings of carbonaceous components, mainly filling open fractures and occasionally enclosed in shock‐melt veins, were found in the recently fallen Tissint Martian meteorite. The presence in shock‐melt veins and the deuterium enrichments (δD up to +1183‰) of these components clearly indicate a pristine Martian origin. The carbonaceous components are kerogen‐like, based on micro‐Raman spectra and multielemental ratios, and were probably deposited from fluids in shock‐induced fractures in the parent rock of Tissint. After precipitation of the organic matter, the rock experienced another severe shock event, producing the melt veins that encapsulated a part of the organic matter. The C isotopic compositions of the organic matter (δ13C = −12.8 to −33.1‰) are significantly lighter than Martian atmospheric CO2 and carbonate, providing a tantalizing hint for a possible biotic process. Alternatively, the organic matter could be derived from carbonaceous chondrites, as insoluble organic matter from the latter has similar chemical and isotopic compositions. The presence of organic‐rich fluids that infiltrated rocks near the surface of Mars has significant implications for the study of Martian paleoenvironment and perhaps to search for possible ancient biological activities on Mars.

Martian Carbon Dioxide

As a primary component of the martian atmosphere and as the primary greenhouse gas for Mars, carbon dioxide has played a role in climate and geological processes during martian history. Niles et al. (p. [1334][1]) present high-precision measurements of the isotopic composition of the martian atmospheric CO2, made in situ by the Mars Phoenix Lander. Atmospheric CO2 on Mars was not enriched in 13C, which implies that volcanic degassing and carbonate formation have been important in the recent past, but it was enriched in 18O, which suggests that low-temperature water-rock interactions have been dominant on Mars. Combined with previous work on martian meteorites, the results suggest that carbonate formation has been active on Mars for the past 200 million years. [1]: /lookup/doi/10.1126/science.1192863

Stable Isotope Measurements of Martian Atmospheric CO 2 at the Phoenix Landing Site

Carbon dioxide is a primary component of the martian atmosphere and reacts readily with water and silicate rocks. Thus, the stable isotopic composition of CO2 can reveal much about the history of volatiles on the planet. The Mars Phoenix spacecraft measurements of carbon isotopes [referenced to the Vienna Pee Dee belemnite (VPDB)] [delta13C(VPDB) = -2.5 +/- 4.3 per mil (per thousand)] and oxygen isotopes [referenced to the Vienna standard mean ocean water (VSMOW)] (delta18O(VSMOW) = 31.0 +/- 5.7 per thousand), reported here, indicate that CO2 is heavily influenced by modern volcanic degassing and equilibration with liquid water. When combined with data from the martian meteorites, a general model can be constructed that constrains the history of water, volcanism, atmospheric evolution, and weathering on Mars. This suggests that low-temperature water-rock interaction has been dominant throughout martian history, carbonate formation is active and ongoing, and recent volcanic degassing has played a substantial role in the composition of the modern atmosphere.

Escape of the Atmosphere of Rotating Planet

The problems of escape of a planetary atmosphere is reviewed. Formulae are derive for the rates of loss of mass and angular momentum from a unit area and from the whole planetary surface. The resulting formulae are applied to find the residence times of H, O, N2, O2 and CO2 in Martian atmosphere. All constituents are so stable while hydrogen is never stable and cannot be retained to my extent. 9 years) if the root mean square velocity of the particle is less than the escape velocity Ve. Valuable discussions were given by (2-4). (5) treated the problem taking into account the effect of orbital motion. The effect of rotation of the planet was introduced by (6) who derived formulae for the rates of loss of mass and angular momentum per unit area of the surface. In this paper formulae are derived to find expressions for the rates of loss of mass and angular momentum per unit area f the surface (including higher order terms than obtained by Burke to applicable for higher rotational velocities), and for the total rates of loss of mass and angular momentum from the whole planetary surface. The two necessary conditions for escape are: 1) the spatial velocity Vs should be larger than the escape velocity Ve. 2) Negligible chance of undergoing collisions. This condition is satisfied at the critical level (base of the exosphere). If ro is the radius of the planet, the critical velocity required for the outgoing particles at a height z above the planet's surface to escape is

A carbon and nitrogen isotope study of Zagami

Samples from the two major lithologies (fine‐ and coarse‐grained) in Zagami have been analyzed for the abundance of carbon and nitrogen and their isotopic compositions. Using the technique of stepped combustion, it was possible to evaluate the distribution of carbon and nitrogen within different species (organic, carbonate, nitrate, etc.) in the samples. Separates of shock‐produced glass and pigeonite were also analyzed for carbon. The majority of the carbon and nitrogen in each sample arises from contaminants (organic materials, absorbed gases, etc.). However, carbon and nitrogen of magmatic origin is released above 600°C (δ13C ∼−24‰; δ15N ∼−5‰). The glass separates contain a minor contribution from trapped Martian atmospheric CO2, in addition to the magmatic component. Zagami appears to contain two generations of carbonate, an isotopically light end‐member with minimum δ13C around −23‰, plus a more 13C‐enriched carbonate. The latter is typical of Martian carbonates formed from fluid in contact with Martian atmospheric CO2, while the former might represent a more primitive source of carbon, and possibly emanate from the carbonate anion present within silicates or phosphates. The spread in δ13C values of carbonates in Martian meteorites clearly points to the operation of at least two processes, each imparting a characteristic carbon isotopic signature. These processes are interpreted within the framework of models that describe the evolution of Zagami‐type basalts on Mars.

Record of fluid-rock interactions on Mars from the meteorite ALH84001.

Allan Hills (ALH) 84001 is the most recently recognized member of a suite of meteorites--the SNCs--that almost certainly originated on Mars. Several factors distinguish ALH84001 from the other SNC meteorites. Preliminary studies suggest that it may be older than other martian meteorites. Moreover, it contains abundant, zoned domains of calcium-iron-magnesium carbonate that are indigenous to the sample and thus may hold important clues regarding near-surface processes on Mars and the evolution of the martian atmosphere. We report here analyses of the carbon and oxygen stable-isotope compositions of the carbonates that place constraints on their formation conditions. Our results imply the presence of at least two chemically distinct carbonates--one Ca,Fe-rich, the other Mg-rich--that are enriched in 13C relative to terrestrial carbonates (delta 13C approximately +41/1000), consistent with martian atmospheric CO2 as the carbon source. The oxygen isotope compositions of the carbonates indicate that they precipitated from a low-temperature fluid in the martian crust. Combined with textural and bulk geochemical considerations, the isotope data suggest that carbonate deposition took place in an open-system environment in which the ambient temperature fluctuated.

An assessment of the nature and origins of the carbon‐bearing components in fines collected during the sawing of EET A79001

Saw dust obtained from the cutting of EET A79001, a meteorite with a presumed Martian origin, has been analyzed for its carbon content and stable isotopic composition in order to assess the sample's potential value for studies aimed at elucidating Martian surface processes. These fines, which are available in plentiful supply, are a useful source of material and are important since they are a representative whole‐rock sample of this complex meteorite. In addition, the fines give an indication of contamination sources which may affect not only the collected sawings but also the sawn surface of the meteorite. A number of contaminants were identified in the fines (e.g. organic materials, Teflon, diamond, and carbon associated with metal). It is considered that the levels of carbon contamination measured represent a worst possible case and hence provide a valuable reference with which to compare other analyses of this sample, or indeed, other Martian meteorites. Evidence was found for an indigenous carbonate component similar to that observed previously in other fractions of the meteorite. However, based on the results presented herein it is not possible to assert that isotopically distinct carbonate minerals of different origins are present in the meteorite. The levels of trapped Martian atmospheric CO2 calculated for the fines are unexpectedly high (∼1 ppm carbon), but this could be influenced by the presence of other, as yet unknown, carbonaceous materials.

Mars: Near‐infrared spectral reflectance of surface regions and compositional implications

Reflectance spectra (0.65–2.50 μm) are presented for 11 Martian areas. The spectral resolution is ∼1½% and the spatial resolution is 1000–2000 km. These are the first high‐quality spectrophotometric data at these wavelengths for regions on the surface. Spectral features previously observed are confirmed and better defined, and a number of important spectral properties are characterized for the first time. The spectra show water ice absorptions in the 1.5‐ and 2.0‐μm regions, which if due to surface frost, would imply the presence of 1 to 2 mg/cm2 H2O. However, other studies have shown that the presence of an unprotected surface frost in late morning is unlikely. Water ice is stable at night even at the equator and might persist until late morning when the air is well undersaturated if it is intimately dispersed in weathering products, especially if clays are present. The dark region spectra indicate about 4 times less water ice than seen in bright regions. Since some bright material is present in dark regions there may be no water ice associated with the dark materials themselves. This tends to confirm that weathering products (thought to be more abundant in bright regions) are involved in the mechanism that allows temporary persistance of unstable water ice. The presence of weak 2.3‐μm features in many of the spectra are consistent with the presence of hydroxylated magnesium‐rich minerals such as sheet silicates (serpentine, talc, and magnesian smectites) or amphiboles (anthophyllite). The apparent absence of a 2.2‐μm absorption implies that montmorillonite may not be a major component of the Martian regolith. Many of the spectra also show an apparent absorption at 1.9 μm, in the wing of the 2.0‐μm Martian atmospheric CO2 absorption, which would indicate bound molecular water. Observed dark regions have distinctive near‐infrared spectral shapes, previously not well determined, which are characteristic of thin semi‐transparent alteration coatings overlying dark unaltered rock. Previously observed ferrous‐ and ferric‐iron absorptions in the 1‐μm region are better defined by these new data. Clinopyroxene (augite) is definitely present, but olivine is not spectrally apparent.

Mars: Near‐infrared spectral reflectance and compositional implication

Several distinct absorption features, some recognized for the first time, are evident in a newly obtained reflectance spectrum (λλ = 0.62‐2.6 μm, λ/Δλ = 83) of the integral disc of Mars. The effects of Martian atmospheric CO2 have been removed from the spectrum to arrive at a reflectance spectrum that we believe is due mostly to surface material. Absorptions, at 1.22, 1.55, and 2.05 μ are interpreted to indicate the presence of H2O ice plus highly desiccated mineral hydrate, although an H2O ice phase with strongly shifted fundamental frequencies cannot be ruled out. Ferrosilicate and ferric oxide bands near and shortward of 1.0 μm are confirmed. The new observations were made on April 21–23, 1976, universal time, at the 2.24‐m telescope on Mauna Kea, Hawaii, using a newly developed infrared spectrometer.