[1] To understand the aqueous history of Mars, it is critical to constrain the alteration mineralogy of the Martian surface. Previously published analyses of thermal infrared (l = 6–25 mm) remote sensing data of Mars suggest that dark regions have 15–20% clay minerals. However, near-infrared (l = 1–3 mm) spectral results generally do not identify widespread clay minerals. Thermal infrared detec...

liquid crystal, colloid, SAXS Suspensions of three different clays in K15, a thermotropic liquid crystal have been studied by optical microscopy and small angle X-ray scattering. The three clays were Claytone AF, a surface treated natural montmorillonite, Laponite RD, a synthetic hectorite and mined Sepiolite. The Claytone and Laponite were sterically stabilized whereas Sepiolite formed a relat...

A simple formalism is presented to model the behaviour of expansive clays. Two levels of structure are considered. The behaviour of the macrostructure follows the model developed for unsaturated materials by Alonso et al. [Géotechnique 40 (3) (1990) 405–430]. The behaviour of the microstructure is adapted from the work of Gens and Alonso [Can. Geotech. J. 29 (1992) 1013–1032] in order to includ...

Global warming during the Paleocene-Eocene thermal maximum (PETM) was associated with the release of large amounts of 12 C-enriched carbon, as reflected in the carbon isotope excursion (CIE) observed globally in sedimentary records. The New Jersey shelf PETM sequences are expanded relative to deep-sea settings, offering high temporal resolution to unravel the pathway of carbon release, although...

Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly,...

Progressive failure is common in many natural clays of strain-softening behavior and may affect the bearing capacity foundations placed on such soils. The progressive might be insignificant for small structures where mobilized strains are generally uniform within failed soil mass. This places a demerit to applications knowledge obtained from physical model tests prototype. study aims understand...

The industrial practice used to produce furfural is the dehydration of pentoses, which is carried out using highly corrosive and contaminating mineral acid catalysts. Because of the ecological and toxicological threats of this process and the complexity of product separation associated with these substances, the development of new acid solid catalysts has expanded in recent years. The present w...

10 11 We measured the self-potential (SP) response to advective transport of KCl 12 concentration fronts through two laboratory-scale sand-bodies with different 13 mineralogical composition. In pure quartz sand, the amplitude and polarity of the SP 14 signals agreed with a previously published model. In sand containing 3 % potassic 15 feldspars and 1 % micas and clays, the shape of the SP respo...

Debris flows are responsible for the loss of hundreds of lives and millions of dollars of property damage each year worldwide (Costa, 1987). As a result of extensive property damage and loss of life there is a pressing need to go beyond just describing the nature and extent of debris flows as they occur. Most of the research into debris-flow initiation has centered on rainfall, slope angle, and...

As a means of distinguishing between the broad groups of flay minerals, chemical analysis may be a valuable supijlement to other methods, but rarely will it remove the necessity for other methods, X-ray analysis in particular. The twoand three-layer clay minerals may be distinguished by the SiOj • AlzOs ratio or SiOz • sesquioxide ratio, but these ratios do not provide criteria for dividing eit...