Book•
The x-ray identification and crystal structures of clay minerals
01 Jan 1961-
About: The article was published on 1961-01-01 and is currently open access. It has received 966 citations till now. The article focuses on the topics: Clay minerals.
Citations
More filters
TL;DR: In this article, a coupe stratigraphique de reference couvrant une partie du Pleistocene superieur is analyzed, and the results of the pollen analysis evoque un cycle complet de la vegetation and du climat.
Abstract: Dans la region de la baie Saint-Laurent, s'etend, le long de la cote, une coupe stratigraphique de reference couvrant une partie du Pleistocene superieur. Les depots meubles, parmi lesquels 9 unites lithostratigraphiques sont denombrees, reposent sur une plateforme d'abrasion marine attribuee au dernier interglaciaire. La pollenanalyse des depots a permis de mettre en evidence deux episodes climatiques distincts: 1) le premier, dans la partie inferieure de la coupe, est represente par un lit de tourbe ligneuse (> 38 300 BP; GSC-283) compacte et les couches limono-sableuses entre lesquelles il est interstratifie. La pollenanalyse evoque un cycle complet de la vegetation et du climat. On observe le passage progressif d'une vegetation ouverte de type toundra a l'occupation du paysage par une foret de coniferes avec quelques elements decidus. Un brusque appauvrissement du couvert forestier, considere comme un retour aux conditions initiales, lui succede. Cet episode, meme a son optimum climatique, reflete des conditions plus fraiches que celles de l'Actuel. Il est associe a l'un des intervalles de rechauffement du Wisconsinien inferieur ou moyen et correspond a l'une des phases isotopiques oceaniques 5c, 5a ou debut de 3; 2) le deuxieme episode, dans la partie superieure de la coupe, est represente par une unite stratifiee limono-sableuse fossilifere et des lits limono-sableux interstratifies dans des rudites. Les assemblages faunistiques et polliniques (pollen et dinoflagelles) indiquent un remaniement de materiaux glacio-marins. L'analyse pollinique traduit une vegetation de toundra ou de toundra forestiere. Cet episode reflete des conditions climatiques compatibles avec l'englacement d'une partie de l'ile du Cap-Breton.
10 citations
TL;DR: In this article, a limited laboratory studies on shear strength, consolidation and chemical analysis were carried out to examine the geotechnical characteristics of marine sediments collected from the north-east coastal region of Singapore.
10 citations
TL;DR: X-ray diffraction and wet chemical analytical data obtained on geologic samples representing commercial talc ore deposits of high purity and on processed samples representing talc found in consumer talcum products indicate that clinochlore and penninite are the two chlorite minerals most commonly found in all talc samples irrespective of origin or source.
Abstract: Chlorite is the most common accessory mineral group found in high purity talc ore used in cosmetic or pharmaceutical consumer talcum products. X-ray diffraction and wet chemical analytical data obtained on geologic samples representing commercial talc ore deposits of high purity and on processed samples representing talc found in consumer talcum products indicate that clinochlore and penninite are the two chlorite minerals most commonly found in all talc samples irrespective of origin or source, but sheridanite is also found in some samples representing talc deposits that are associated with serpentinite rocks. The chlorite minerals exhibit certain well-defined X-ray diffraction characteristics which differentiate them from each other as well as from those of serpentine minerals, including the hazardous chrysotile asbestos.
10 citations
TL;DR: In this paper, the effect of the pH on B adsorption and the adorption kinetics were compared to raw vermiculite and fitted well with the Freundlich equation.
Abstract: Micron-grade natural vermiculite was modified by several physical and chemical treatments in order to increase the adsorption capacity of this material for B. A thermal exfoliation ( T = 600°C) of pristine material, a chemical exfoliation through reaction with hydrogen peroxide (H2O2 35%), or grafting of a specific B complexant ( i.e. N-methyl-D-glucamine: NMDG) led to an increase in the uptake of B at low initial concentrations of the aqueous solutions ([B] ≈ 5 mg L−1). The more efficient material is the NMDG-grafted clay, for which the adsorption uptake is four times greater than that of raw vermiculite, and reaches 0.04 mmol g−1. For all modified materials, the effect of the pH on B adsorption and the adsorption kinetics were studied and compared to raw vermiculite. Adsorption isotherms were also plotted and fitted well with the Freundlich equation.
10 citations
TL;DR: In this article, four soils derived from recent volcanic ash were studied along an altitudinal transect on the east slope of the central Cordillera of Colombia, South America.
10 citations