Introduction: Impact-generated hydrothermal systems may have caused widespread alteration of the crust on early Mars. We previously explored the range of alteration products using several Martian meteorites as crustal proxies: LEW88516 [1-3], Dhofar 378, Chassigny [4], and Nakhla [5]. Overall, the dominating alteration phases are oxides, hydroxides, clay minerals, and other hydrous silicates. O...

It has been considered that the corrosion of passive metals and alloys is not caused by the active metal-dissolution but the dissolution of a nonporous passive oxide film in aqueous solution. The corrosion current density of iron(1)(2), chromium(3) and their alloys(4) is independent of the potential in all the range of passivity, although depending upon the pH of solution. Vetter(1) explained s...

We report the first systematic study of H2O speciation in dacitic melt with total dissolved H2O ranging from 1.4 to 2.6 wt%. Samples were heated in a one-atmosphere tube furnace at 480–590 °C for certain durations and then quenched in water or air. Species concentrations were measured with Fourier transform infrared (FTIR) spectroscopy. At a given temperature, the equilibrium constant for the r...

The high-pressure phases denoted ANH-B, hydrous B, and SHY-B (Finger et aI., 1991; Pacalo and Parise, 1992), containing both [4]Siand [6]Si, are members of a homologous (polysomatic) series in which the [4]Si-containing portions are cOlnposed of olivine-like (0) slabs alternating with thinner goethite-like (G) slabs in the ordered arrangements 000, OOOG, and OG. Leucophoenicite, OOOG, containin...

The coherent dehydration of pure-Mg wadsleyite has been investigated by single-crystal X-ray diffraction at high temperature and room pressure. Hydrous wadsleyite with 2.8 wt% H2O has monoclinic unit-cell parameters of a = 5.6693(4), b = 11.571(1), c = 8.2407(5) Å, = 90.209(3) , and V = 540.59(7) Å. Dehydration begins at 635 K with an abrupt increase in the a-axis and decrease in b. After dehyd...

Rhodium nanoparticles (NPs) effectively catalyze the decomposition of hydrous hydrazine to produce hydrogen under ambient reaction conditions. Rh(0) NPs with a particle size of approximately 5 nm prepared in the presence of hexadecyltrimethyl ammonium bromide show higher catalytic activity.

[1] In this study, we used porosity to assess the compaction state of the Nankai accretionary wedge sediments and any implications for stress and pore pressure. However, hydrous minerals affect porosity measurements, and accounting for them is essential toward defining the interstitial porosity truly representative of the compaction state. The water content of sediments was measured in core sam...

The objectives of this study were [1] to conduct some experimental tests of the surface precipitation adsorption model, and [2] to work on the development of a simple yet widely applicable approach to modelling adsorption of inorganic ions on oxide surfaces. The latter represents the first portion of our continuing effort to develop a data base for adsorption of inorganic contaminants in oxide ...