The 5-band Clementine UVVIS data at 100 m/pixel were used to examine the compositions of 75 large and small lunar pyroclastic deposits (LPDs), and these were compared to representative lunar maria and highlands deposits. Results show that the albedo, spectral color, and inferred composition of most LPDs are similar to those of low-titanium, mature lunar maria. These LPDs may have consisted larg...

Introduction: Numerous studies over the past decade have demonstrated that microbial life rapidly colonizes terrestrial subaqueous volcanic glass [1-5]. Evidence for microbial alteration of terrestrial subaqueous volcanic rocks has been reported from modern ocean crust, ophiolites, and Archean greenstone belts [1-5]. Microbial alteration structures with characteristic granular and tubular morph...

The freezing temperatures of hundreds of water drops with radii 20–50 lm containing known average concentrations of suspended, mostly micronto submicron-sized, volcanic ash particles composed of SiO2-rich glass were recorded using optical microscopy. As expected, the ash suppresses supercooling, and in contrast to earlier studies of much larger ash particles, the median freezing temperature cle...

[1] With the prevalence of glass and molten silicates in volcanic environments, and the important role of surface emissivity in thermal infrared (TIR) measurements, it is imperative to characterize accurately the spectral features associated with silicate glasses and melts. A microfurnace has been developed specifically for use with a laboratory Fourier transform infrared (FTIR) spectrometer to...

Mechanical relaxation behaviour of various natural volcanic glasses have been investigated in the temperature range RT − 1000C using special low frequency flexure (f≈0.63Hz) pendulum experiments. The rheological properties complex Young’s modulus M⋆(ω, τ) and internal friction Q−1(ω, τ) have been studied from a pure elastic solid at room temperature to pure viscous melt at log(η[Pas]) = 8. The ...

Thirty silicate glasses were synthesized as realistic analogs to those expected to exist on Mars, the Moon, and Mercury. Samples were measured using visible/near-infrared and Mössbauer spectroscopy to determine the effects of varying bulk chemistry, oxygen fugacity, and temperature on spectral properties. For Martian glasses, the fO2 during fusion strongly affects absorption band intensities in...

Introduction: Clay minerals are the most common alteration products of water-rock-gas interactions on Earth. Because these hydrous alteration minerals are thermodynamically stable over a wide range of P-T-x conditions [1], significant amounts of clay may have also formed in Martian environments where liquid water or water vapor was present. It has been speculated that liquid water or vapor may ...

Interactions with volcanic gases in eruption plumes produce soluble salt deposits on the surface of volcanic ash. While it has been postulated that saturation-driven precipitation of salts following the dissolution of ash surfaces by condensed acidic liquids is a primary mechanism of salt formation during an eruption, it is only recently that this mechanism has been subjected to detailed study....