Liquidus temperature of plagioclase and pyroxene in andesitic melts at one atmosphere.

H2O diffusion in dacitic and andesitic melts

The diffusion of water in dacitic and andesitic melts was investigated at temperatures of 1458 to 1858 K and pressures between 0.5 and 1.5 GPa using the diffusion couple technique. Pairs of nominally dry glasses and hydrous glasses containing between 1.5 and 6.3 wt.% dissolved H2O were heated for 60 to 480 s in a piston cylinder apparatus. Concentration profiles of hydrous species (OH groups an...

Prospects and challenges of iron pyroelectrolysis in magnesium aluminosilicate melts near minimum liquidus temperature.

Although steel production by molten oxide electrolysis offers potential economic and environmental advantages over classic extractive metallurgy, its feasibility is far from being convincingly demonstrated, mainly due to inherent experimental difficulties exerted by harsh conditions and lack of knowledge regarding relevant mechanisms and physico-chemical processes in the melts. The present work...

Preferential low-pH dissolution of pyroxene in plagioclase–pyroxene mixtures: Implications for martian surface materials

Acid weathering of plagioclase–pyroxene mixtures has been investigated with an open system kinetic dissolution model. The modeling reveals that elevated plagioclase/pyroxene ratios observed in some low-albedo martian regions and atmospheric dust could be partially caused by preferential dissolution of pyroxenes at pHs below ∼3–4. Surface materials with smaller grain sizes, affected by lower pH ...

Petrography, geochemistry and determination of temperature and pressure of crystallization of pyroxene and plagioclase minerals in diabasic and lamprophyre dykes of Jupar block (south of Kerman)

A set of diabasic and lamprophyre dykes, trending NW-SE, cut the Neogene volcanic rocks that exposed in the south of Kerman city and west of Glomac village. They are characterized by porphyritic and glomeroporphyry textures. Lamprophyres contain course- grained phenocryst of olivine- pyroxene- amphibole in a matrix containing feldspars. diabasic rocks are dominated by main minerals including di...

PREFERENTIAL LOW-pH DISSOLUTION OF PYROXENE IN PLAGIOCLASE-PYROXENE MIXTURES AND IMPLICATIONS FOR MARTIAN LOW-ALBEDO REGIONS