Hydrous Silicates and Water on Venus

Zolotov, M. Yu.; Fegley, B.; Lodders, K.

doi:10.1006/icar.1997.5838

Cited by 41 publications

(27 citation statements)

References 53 publications

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“…Sulfur dioxide is the third most abundant gas in Venus' subcloud atmosphere with a mixing ratio of 150 ppmv (Lodders and Fegley 1998). Zolotov et al (1997) calculated that at equilibrium, tremolite will be attacked by SO 2 to form anhydrite (CaSO 4 ), enstatite, quartz, and water vapor. We checked the importance of this postulated reaction by heating tremolite in a 1% SO 2 -99% CO 2 gas mixture at 1106 K for 13 days.…”

Section: Discussionmentioning

confidence: 99%

“…If there had been more water in Venus' past, it is possible that hydrous minerals formed on or within the surface. However, equilibrium thermodynamic calculations predict that these minerals are unstable at venusian surface temperatures and pressures (Zolotov et al 1997). Notwithstanding, the planetary community has debated the existence of hydrous minerals on Venus for over 30 years without knowledge of the rate at which hydrous minerals decompose (e.g., Mueller 1964, Lewis 1970, Khodakovsky 1982.…”

Section: Introductionmentioning

confidence: 99%

“…This gives a water partial pressure of ∼3 millibar at the surface of Venus. In order for tremolite to be currently stable on the plains of Venus at 740 K, the atmospheric partial pressure of water vapor must be at least 6 bar to prevent tremolite decomposition via the following reaction (Zolotov et al 1997 …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Water on Venus: New Insights from Tremolite Decomposition

Johnson¹

2000

Icarus

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Water on Venus: New Insights from Tremolite Decomposition

Johnson¹

2000

Icarus

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“…The calculations use plausible mineral buffers -that is reactions involving minerals that are found in the same rock types: felsic rocks with free silica (e.g., like Earth's continental crust), or mafic rocks without free silica (e.g., like Earth's basaltic oceanic crust). We used all buffers considered by Lewis (1970), Fegley and Treiman (1992), and the phyllosilicate buffers considered by Zolotov et al (1997) in our model (see Appendix 1). Figure 1a shows results for this method applied to Venus.…”

Section: Venus Surface-atmosphere Equilibrium Modelmentioning

confidence: 99%

Atmospheric Chemistry of Venus-Like Exoplanets

Schaefer

Fegley

2011

ApJ

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Abstract:We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibria between the atmosphere and lithosphere, as on Venus. The results of our calculations place constraints on abundances of spectroscopically observable gases, the surface temperature and pressure, and the mineralogy of the planetary surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by current and proposed space observatories such as the Hubble Space Telescope (HST), Spitzer, James Webb Space Telescope (JWST), and Darwin.

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“…Unfortunately, XRF does not provide information on lighter elements, and therefore, hydrogen content, and thus hydration in minerals, is unknown. Modeling of minerals under Venus conditions suggests the stability of hydrated minerals such as hydrous silicates, as well as OH − , containing nominally anhydrous minerals such as pyroxenes [13]. Because this subject of mineralogical alteration and weathering in the Venus environment is of great interest, it perhaps suggests the need to get below the surface to access unweathered materials for analysis.…”

Section: B Mineralogy Of Mars and Venusmentioning

confidence: 99%

Time-resolved Raman spectroscopy for in situ planetary mineralogy

2010

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Planetary mineralogy can be revealed through a variety of remote sensing and in situ investigations that precede any plans for eventual sample return. We briefly review those techniques and focus on the capabilities for on-surface in situ examination of Mars, Venus, the Moon, asteroids, and other bodies. Over the past decade, Raman spectroscopy has continued to develop as a prime candidate for the next generation of in situ planetary instruments, as it provides definitive structural and compositional information of minerals in their natural geological context. Traditional continuous-wave Raman spectroscopy using a green laser suffers from fluorescence interference, which can be large (sometimes saturating the detector), particularly in altered minerals, which are of the greatest geophysical interest. Taking advantage of the fact that fluorescence occurs at a later time than the instantaneous Raman signal, we have developed a time-resolved Raman spectrometer that uses a streak camera and pulsed miniature microchip laser to provide picosecond time resolution. Our ability to observe the complete time evolution of Raman and fluorescence spectra in minerals makes this technique ideal for exploration of diverse planetary environments, some of which are expected to contain strong, if not overwhelming, fluorescence signatures. We discuss performance capability and present time-resolved pulsed Raman spectra collected from several highly fluorescent and Mars-relevant minerals. In particular, we have found that conventional Raman spectra from fine grained clays, sulfates, and phosphates exhibited large fluorescent signatures, but high quality spectra could be obtained using our time-resolved approach.

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Hydrous Silicates and Water on Venus

Cited by 41 publications

References 53 publications

Water on Venus: New Insights from Tremolite Decomposition

Water on Venus: New Insights from Tremolite Decomposition

Atmospheric Chemistry of Venus-Like Exoplanets

Time-resolved Raman spectroscopy for in situ planetary mineralogy

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