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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.
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TL;DR: In this paper, water and sediment samples (n = 51 and 182, respectively) were collected from sabkhas systems of the Red Sea coast, which extends between Jeddah city and the town of Yanbu Al-Bahar and is bounded by latitudes 21°30′ and 24°00′N and longitudes 38°00´ and 39°30´E.
Abstract: “Sabkha” is a term used to describe the coastal flats and salt marches deposited in lagoonal areas under arid conditions. In this study, water and sediment samples (n = 51 and 182, respectively) were collected from sabkhas systems of the Red Sea coast, which extends between Jeddah city and the town of Yanbu Al-Bahar and is bounded by latitudes 21°30′ and 24°00′N and longitudes 38°00′ and 39°30′E. The collected sediment samples were subjected to sedimentological and mineralogical analyses using grain size and X-ray diffraction techniques. The water samples were subjected to hydrochemical analyses using several standard procedures. The study found that climatic conditions in the Red Sea coastal plain sabkhas lead to the formation of marine brines of magnesium-sodic to chloride type with neutral pH value. Because of the evaporation of the groundwater, the evaporite minerals, especially aragonite, halite, and gypsum, were precipitated. The present study shows that this resulted in an increase in the ...
16 citations
01 Jan 1968
TL;DR: In this paper, the Mg/Ca ratio of carbonate sediments from a vertical stratigraphic section through the Lower Keuper Formation (Triassic) in the Weser area (North Western Germany) was evaluated as to their genetic aspects under consideration.
Abstract: 55 samples of carbonate sediments from a vertical stratigraphic section through the Lower Keuper Formation (Triassic) in the Weser area (North Western Germany) were evaluated as to their Mg/Ca ratio, taking their genetic aspects under consideration. Subsequently, the dolomite/calcite ratio, the Ca/Mg ratio of the dolomites, and the Mg-content of the calcite are discussed.
16 citations
TL;DR: In this paper, several different X-ray diffraction methods are described and a single suitable procedure is chosen and described in detail, including analysis of both clay and non-clay minerals and qualitative and quantitative interpretation.
Abstract: Mineralogical studies of sedimentary rocks or sedimentary deposits are often required for engineering geological projects. X-ray diffraction analytical techniques are usually employed for this purpose but these methods are often complex and involved. Several different X-ray diffraction methods are described and a single suitable procedure is chosen and described in detail. The chosen method includes analysis of both clay and non-clay minerals and qualitative and quantitative interpretation.
16 citations
01 Jan 1983
TL;DR: In the study of phyllosilicate diagenesis two problems must be immediately considered: the chemical composition of the phases concerned and the possibility of metastable reactions as well as slow reaction rates among the phases present.
Abstract: In the study of phyllosilicate diagenesis two problems must be immediately considered:
1
— The chemical composition of the phases concerned and
2
— The possibility of metastable reactions as well as slow reaction rates among the phases present.
16 citations
TL;DR: In this article, the sorption of 2,2′-bipyridine onto some clays and oxides was studied as a function of concentration, pH, time and the exchangeable cation of the clays.
Abstract: The sorption of 2,2′-bipyridine onto some clays and oxides was studied as a function of concentration, pH, time and the exchangeable cation of the clays. The reaction was found to include both physical, cation exchange, and chemisorption, was irreversible and multilayered at high concentrations. The sorption was also pH dependent attaining a maximum in the pH range 4.5 to 5.5 depending on the sorbent; this dependence was attributed to chemisorption. The maximum in sorption was observed to take place above the pH value where the molecular form is the only bipyridine species present in solution thus indicating its preference by the sorbents over the positive species. Chemisorption, ion exchange against metalic cations and molecular aggregation on the surface are the factors thought to be responsible for the desorption of bipyridine at pH values beyond that at the maximum sorption.
Sorption von 2,2′-Bipyridin durch Tone und Oxide
Die Sorption von 2,2′-Bipyridin durch einige Tonminerale und Oxide wurde in Abhangigkeit von Konzentration, pH-Wert, Zeit und Kationenbelegung der Tone untersucht. Die Bindung erfolgte durch Kationenaustausch und Chemisorption und war irreversibel; bei hoher Bipyridin-Konzentration wurden mehrere Molekulschichten angelagert.
Die Sorption war auch pH-abhangig und erreichte, abhangig vom Sorbent, ein Maximum im pH-Bereich von 4,5 bis 5,5. Die pH-Abhangigkeit wurde auf Chemisorption zuruckgefuhrt.
Die starkste Sorption trat oberhalb desjenigen pH-Wertes ein, bei dem Bipyridin nur als Molekul in der Losung vorliegt: Chemisorption dominiert also gegenuber Austauschbindung.
16 citations