H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO2. Concurrent evolution of O2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.

/pdf/volatile-and-organic-compositions-of-sedimentary-rocks-in-rs4zyerdbx.pdf

Volatile and organic compositions of sedimentary rocks in Yellowknife Bay, Gale crater, Mars.

Publisher Summary This chapter focuses on organic catalysis over crystalline alumiosilicates. Zeolites are crystalline aluminosilicates composed of SiO4 and AlO4 tetrahedra arranged in various geometric patterns. The chapter discusses reactions over a wide variety of crystalline aluminosilicates and emphasizes on catalysis over X- and Y-type faujasites. Unusual opportunities for organic catalysis were found to exist when these were base exchanged to substantially eliminate their alkali metal content. It is shown that catalytic activity in ion-exchanged faujasites is influenced by cation type, cation location in the lattice, zeolite Si/Al ratio, and the presence of proton donors. The existence of several crystallographically distinct cation locations provides the basis for a potential heterogeneity of sites in catalytic reactions. The Linde workers made calculations for the electrostatic field strengths of surface cations near SII and SIII in an X-type zeolite of Si/Al ratio 1.0 and in a Y-type zeolite of Si/Al ratio 2.0. In both cases, the fields has been significantly larger near SIII than SII at a distance of 2 Ǻ from the center of the cation for the univalent cation-exchanged systems, provided both sites are occupied.

Organic Catalysis over Crystalline Aluminosilicates

The Sample Analysis at Mars instrument evolved gas analyzer (SAM-EGA) has detected evolved water, H2, SO2, H2S, NO, CO2, CO, O2 and HCl from two eolian sediments and nine sedimentary rocks from Gale Crater, Mars. These evolved gas detections indicate nitrates, organics, oxychlorine phase, and sulfates are widespread with phyllosilicates and carbonates occurring in select Gale Crater materials. Coevolved CO2 (160 ± 248 - 2373 ± 820 μgC(CO2)/g), and CO (11 ± 3 - 320 ± 130 μgC(CO)/g) suggest organic-C is present in Gale Crater materials. Five samples evolved CO2 at temperatures consistent with carbonate (0.32± 0.05 - 0.70± 0.1 wt.% CO3). Evolved NO amounts to 0.002 ± 0.007 - 0.06 ± 0.03 wt.% NO3. Evolution of O2 suggests oxychlorine phases (chlorate/perchlorate) (0.05 ± 0.025 - 1.05 ± 0.44wt. % ClO4) are present while SO2 evolution indicates the presence of crystalline and/or poorly crystalline Fe- and Mg-sulfate and possibly sulfide. Evolved H2O (0.9 ± 0.3 - 2.5 ± 1.6 wt.% H2O) is consistent with the presence of adsorbed water, hydrated salts, interlayer/structural water from phyllosilicates, and possible inclusion water in mineral/amorphous phases. Evolved H2 and H2S suggest reduced phases occur despite the presence of oxidized phases (nitrate, oxychlorine, sulfate, carbonate). SAM results coupled with CheMin mineralogical and APXS elemental analyses indicate that Gale Crater sedimentary rocks have experienced a complex authigenetic/diagenetic history involving fluids with varying pH, redox, and salt composition. The inferred geochemical conditions were favorable for microbial habitability and if life ever existed, there was likely sufficient organic-C to support a small microbial population.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016JE005225

Evolved gas analyses of sedimentary rocks and eolian sediment in Gale Crater, Mars: Results of the Curiosity rover's sample analysis at Mars instrument from Yellowknife Bay to the Namib Dune

Kinetics of non‐isothermal sorption in molecular sieve crystals

The Sample Analysis at Mars instrument evolved gas analyzer (SAM-EGA) has detected evolved water, SO2, NO, CO2, CO, O2, and HCl from two eolian sediments and nine sedimentary rocks from Gale Crater, Mars. The SAM-EGA heats samples to 870°C and measures evolved gas releases as function of temperature. These evolved gas detections indicate nitrates, organics, oxychlorine phase, and sulfates are widespread with phyllosilicates and carbonates occurring in select Gale Crater materials. CO2 and CO evolved at similar temperatures suggesting that as much as 2373 ± 820 μgC/g may occur as organic carbon in the Gale Crater rock record while relatively higher temperature CO2 detections are consistent with carbonate (<0.70 ± 0.1 wt % CO3). Evolved NO amounts up to 0.06 ± 0.03 wt % NO3 have been detected while O2 detections suggests chlorates and/or perchlorates (0.05 to 1.05 wt % ClO4) are present. Evolution of SO2 indicated the presence of crystalline and/or poorly crystalline Fe and Mg sulfate and possibly sulfide. Evolved H2O (0.9 - 2.5 wt% H2O) was consistent with the presence of adsorbed water, hydrated salts, interlayer/structural water from phyllosilicates, and possible inclusion water in mineral/amorphous phases. Evolved H2S detections suggest that reduced phases occur despite the presence of oxidized phases (nitrate, oxychlorine, sulfate, and carbonate). SAM results coupled with CheMin mineralogical and Alpha-Particle X-ray Spectrometer elemental analyses indicate that Gale Crater sedimentary rocks have experienced a complex authigenetic/diagenetic history involving fluids with varying pH, redox, and salt composition. The inferred geochemical conditions were favorable for microbial habitability and if life ever existed, there was likely sufficient organic C to support a small microbial population.

/pdf/evolved-gas-analyses-of-sedimentary-rocks-and-eolian-116ak5n2vf.pdf

Evolved Gas Analyses of Sedimentary Rocks and Eolian Sediment in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars Instrument.

Catalytic effect of metal oxides on thermal decomposition reactions. II. Catalytic effect of metal oxides on the thermal decomposition of potassium chlorate and potassium perchlorate as detected by thermal analysis methods

Catalytic effect of metal oxides on thermal-decomposition reactions. I. The mechanism of the molten-phase thermal decomposition of potassium chlorate in mixtures with potassium chloride and potassium perchlorate

Diffusion of ethane in modified synthetic zeolites

Rapid sorption processes on granular zeolite

Sorption rates and solubilities of He, H2, Ar, CHt, and Freon-21 were obtained on a large grain of natural chabazite and compared to the results reported earlier on a powder sample originating from tho same specimen. A graphical method of deriving apparent diffusion coefficients at various stages of the sorption experiments is described and used. The dependence of the diffusion coefficients on sample grain size and the degree to which the sorption processes can be described by a single diffusion coefficient are used to infer on the principal types of crystalline disorder present. Certain modifications of the molecular sieve effect are found to lend further support to this interpretation. Die Diffusionsgeschwindigkeiten und Löslichkeiten von He, H2, Ar, CHi und Freon-21 in einem großen Korn von natürlichem Chabasit wurden gemessen und mit früheren Ergebnissen an einem Pulver gleicher Herkunft verglichen. Zur Auswertung der scheinbaren Diffusionskoeffizienten zu Beginn und gegen Ende der Sorption wurde eine graphische Methode entwickelt. Die Korngrößenabhängigkeit der Diffusionskoeffizienten und ihre Veränderung während eines bestimmten Experiments geben Aufschluß über die wichtigsten Defekte, die vorliegen. Weitere Befunde, die mit den bekannten Molekularsieb-Eigenschaften dieses Zeoliten zusammenhängen, stützen die obige Interpretation.

Winfried K. Rudloff

Papers

Catalytic effect of metal oxides on thermal decomposition reactions. II. Catalytic effect of metal oxides on the thermal decomposition of potassium chlorate and potassium perchlorate as detected by thermal analysis methods

Catalytic effect of metal oxides on thermal-decomposition reactions. I. The mechanism of the molten-phase thermal decomposition of potassium chlorate in mixtures with potassium chloride and potassium perchlorate

Diffusion of ethane in modified synthetic zeolites

Rapid sorption processes on granular zeolite

Gaseous Diffusion in a Natural Zeolite in Relation to Crystalline Disorder