Theoretical approaches to the thermochemistry of silicate anions have so far focused on gas-phase molecular orbital and density functional theory (DFT) calculations. These calculations predict that in the presence of hydroxide ligands the most stable singly charged anion of the silicic acid H4SiO4 is the five-coordinated anion H5SiO5 . However, experimental evidence from in situ nuclear magneti...

Biglar Permo-Triassic bauxite deposit is located in ~15 km northwest of Abgarm, southwest of Ghazvin province, west of central Iran. It consists of 8 stratiform and discontinuous bauxite lenses lying along the contact of Ruteh (Permian) and Elika (Triassic) carbonate formations. Petrographically, the bauxite ores exhibit collomorphic-fluidal, pseudo-breccia, pseudo-porphyritic, panidio-morphic-...

The Richmond Mine of the Iron Mountain copper deposit contains some of the most acid mine waters ever reported. Values of pH have been measured as low as -3.6, combined metal concentrations as high as 200 g/liter, and sulfate concentrations as high as 760 g/liter. Copious quantities of soluble metal sulfate salts such as melanterite, chalcanthite, coquimbite, rhomboclase, voltaite, copiapite, a...

In developing the Field Investigation Report for the Waste Management Area S-SX at the Hanford Site, Cs was the only gamma emitting radionuclide of concern (Knepp 2002). However, in WMA B-BX-BY, the spectral gamma logging data identify seven gamma emitting radionuclides, Cs, Sb, Eu, Eu, Co, U, and U (DOE-GJPO 1998). The geochemical behaviors of several of these radionuclides, Sb and the two eur...

Recent studies have shown that the extraction of water from the mantle due to partial melting beneath mid-ocean ridges may increase the viscosity of the residuum by 2–3 orders of magnitude. We examine this rheological effect on mantle flow and melting of a ridge-centered mantle plume using three-dimensional numerical models. Results indicate that the viscosity increase associated with dehydrati...

-This paper presents the design and development of a Geochemical Expert System prototype (GES) for analyzing solution-mineral interactions in nature. The emphasis is placed on expert system design and knowledge representation. One of the most challenging and research-intensive steps was the identification of the key geochemical characteristics that would enable the expert system to identify sal...