[1] Analyses of MRO/CRISM images of the greater Mawrth Vallis region of Mars affirm the presence of two primary phyllosilicate assemblages throughout a region ∼1000 × 1000 km. These two units consist of an Fe/Mg‐phyllosilicate assemblage overlain by an Al‐phyllosilicate and hydrated silica assemblage. The lower unit contains Fe/Mg‐ smectites, sometimes combined with one or more of these other F...

Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that mor...

[1] Signals from the Shallow Radar were intended to penetrate hundreds of meters or more into Mars, but subsurface reflections are abundant only in known or inferred ice‐rich units and young (middle to late Amazonian), apparently pristine, volcanic units. As volcanic units age, fewer subsurface reflections are detected. Also, no subsurface reflections are detected from any northern hemisphere u...

-The adsorption of the cationic oxidized safranine S + by a Na +, Ni 2+ and Fe 3§ montmorillonite has been studied with X-ray powder diffraction, u.v, visible and i.r. spectroscopy. In solution S + may be protonated: S +, SH e+ and SH~ + have characteristic spectra in the 500-600nm region where the clay structure does not absorb. In the Na + as well as in the Ni 2+ and Fe 3+ clays, the adsorpti...

Pedogenesis can be slow or fast depending on the internal chemical response to environmental forcing factors. When a shift in the external environment does not produce any pedogenic change even though one is expected, the soil is said to be in a state of pedogenic inertia. In contrast, soil properties sometimes change suddenly and irreversibly in a threshold response to external stimuli or inte...

The martian crust is often viewed through the lens of its dominant secondary minerals, Noachian phyllosilicates and Hesperian sulfates, based on orbital spectral observations. However, effects surface exposure spectra these hydrous minerals are not fully understood. We use an environmental chamber to measure changes in near-infrared (NIR) absorptions related H2O smectite (montmorillonite) Mg-su...

Complexes of 1,4-diazabicyclo [2.2.2] octane (triethylene diamine) with smectite and vermiculite were made for the purpose of exposing the internal surfaces of the clays for adsorption of gases and possible catalytic activity. When the diprotonated form of the amine saturated the exchange sites, internal surfaces of the clays were found to be available to nitrogen, ethane, and 2,4-dimethyl pent...

Microclimatic parameters and natural materials were studied in order to assess conservation of the cave complex at Galdar, Gran Canaria. Based on the microclimatic data, experimental simulations were carried out to quantify water retention capacity and water vapour transport kinetics under continuously changing extreme temperatures and relative humidity values. The behaviour of natural construc...

[1] Al-rich phyllosilicates (kaolinite, montmorillonite) have been found in layers overlying Fe/Mg-smectites on Mars, and it has been suggested that this stratigraphy formed through in situ leaching at the surface, similar to terrestrial weathering profiles. We are investigating the remotely sensed signatures of this type of weathering using ten samples from a vertical section of altered Deccan...