scholarly journals Fe-oxide concretions formed by interacting carbonate and acidic waters on Earth and Mars

2018 ◽  
Vol 4 (12) ◽  
pp. eaau0872 ◽  
Author(s):  
H. Yoshida ◽  
H. Hasegawa ◽  
N. Katsuta ◽  
I. Maruyama ◽  
S. Sirono ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Formation Process ◽  
Martian Atmosphere ◽  
Formation Mechanisms ◽  
Fe Oxide ◽  
Ph Buffering ◽  
Dense Carbon Dioxide ◽  
Meridiani Planum ◽  
Acidic Waters ◽  
Early Mars

Spherical Fe-oxide concretions on Earth, especially in Utah, USA, have been investigated as an analog of hematite spherules found in Meridiani Planum on Mars to support interpretations of water-rock interactions in early Mars. Although several formation mechanisms have been proposed for the Fe-oxide concretions on Earth, it is still unclear whether these mechanisms are viable because a precise formation process and precursor of the concretions are missing. This paper presents evidence that Fe-oxide concretions in Utah and newly found Fe-oxide concretions in Mongolia had spherical calcite concretions as precursors. Different formation stages of calcite and Fe-oxide concretions observed, both in Utah and Mongolia, indicate that calcite concretions initially formed within eolian sandstone strata and were dissolved by infiltrating Fe-rich acidic waters to form spherical FeO(OH) crusts due to pH buffering. The similarity between these Fe-oxide concretions on Earth and the hematite spherule occurrences in Meridiani Planum, combined with evidence of acid sulfate water influences on Mars, suggest that the hematite spherules also formed from dissolution of preexisting carbonate spherules possibly formed under a dense carbon dioxide early martian atmosphere.

Consequences of CO2 solubility for hydrate formation from carbon dioxide containing water and other impurities

2014 ◽  
Vol 16 (18) ◽  
pp. 8623-8638 ◽  
Author(s):  
Bjørn Kvamme ◽  
Tatiana Kuznetsova ◽  
Bjørnar Jensen ◽  
Sigvat Stensholt ◽  
Jordan Bauman ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Content ◽  
Upper Bound ◽  
Hydrate Formation ◽  
Pipeline Transport ◽  
Co2 Solubility ◽  
Complex Issue ◽  
Dense Carbon Dioxide

Deciding on the upper bound of water content permissible in a stream of dense carbon dioxide under pipeline transport conditions without facing the risks of hydrate formation is a complex issue.

Synthesis of Large-Size Diamonds by Reduction of Dense Carbon Dioxide with Alkali Metals (K, Li)

2004 ◽  
Vol 108 (14) ◽  
pp. 4239-4241 ◽  
Author(s):  
Zhengsong Lou ◽  
Qianwang Chen ◽  
Yufeng Zhang ◽  
Yitai Qian ◽  
Wei Wang
Keyword(s):  
Carbon Dioxide ◽  
Alkali Metals ◽  
Large Size ◽  
Dense Carbon Dioxide

Lipase-catalyzed long chain fatty ester synthesis in dense carbon dioxide: Kinetics and thermodynamics

2007 ◽  
Vol 41 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Chiara Giulia Laudani ◽  
Maja Habulin ◽  
Željko Knez ◽  
Giovanna Della Porta ◽  
Ernesto Reverchon
Keyword(s):  
Carbon Dioxide ◽  
Fatty Ester ◽  
Ester Synthesis ◽  
Kinetics And Thermodynamics ◽  
Dense Carbon Dioxide ◽  
Long Chain

Polyethylene glycol radical-initiated aerobic propargylic oxidation in dense carbon dioxide

2013 ◽  
Vol 22 (3) ◽  
pp. 363-367 ◽  
Author(s):  
Zhenfeng Diao ◽  
Bin Li ◽  
Bing Yu ◽  
Anhua Liu ◽  
Liangnian He
Keyword(s):  
Carbon Dioxide ◽  
Polyethylene Glycol ◽  
Dense Carbon Dioxide

Palladium-catalysed dehydrogenation of 1-phenylethanol in dense carbon dioxide

2005 ◽  
Vol 225 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Marco Burgener ◽  
Tamas Mallat ◽  
Alfons Baiker
Keyword(s):  
Carbon Dioxide ◽  
Dense Carbon Dioxide

scholarly journals An interpretation of the Mars spectrum taken by the Connes

1971 ◽  
Vol 40 ◽  
pp. 189-189 ◽  
Author(s):  
L. D. Kaplan ◽  
L. D. Gray Young
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Partial Pressure ◽  
Surface Pressure ◽  
Rotational Temperature ◽  
Martian Atmosphere ◽  
Co Concentration

Lines of the 2-0 and 3-0 bands of carbon monoxide and (many) bands of carbon dioxide appear prominently in the Connes' Mars spectrum [1]. Five carbon dioxide bands were measured to construct a curve of growth for CO2 lines formed in the Martian atmosphere [2]. A similar curve of growth was constructed for the 2-0 band of carbon monoxide. From these curves, we have computed the rotational temperature of the atmosphere, the surface pressure, and the abundance of CO and CO2. The surface pressure is found to be approximately equal to the CO2 partial pressure, i.e. ps ~ 5 mb. The CO concentration by volume was found to be slightly less than one part per thousand.

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