A paleokarst fi ll deposit from the Wichita Mountains, south-central Oklahoma, United States, consists primarily of sparry calcite, Fe-sulfi des, and goethite. Previous cement-stratigraphic studies and paleontological fi nds suggest that calcite mineralization was initiated during Permian time, whereas goethite and other oxides apparently formed from oxidation of preexisting Fe-sulfi des during...

The physico-chemical and mineralogical properties of a clay mineral deposit in Omialafara Ifon Ose Local Government Area Ondo State, Nigeria was evaluated using standard methods. results the study revealed that consisted phyllosilicate minerals- lizardite aluminian, clinochlore feroanB, sepiolite ferrian , neotocite; others were quartz, goethite evenkite very rare hydrocarbon mineral. minerals ...

Slag-containing pastes and concretes were analysed by element-specific synchrotron-based techniques to determine the speciation of iron on crushed materials through spatially resolved micro-spectroscopic studies. The investigated cement samples hydrated either in laboratory, or exposed river sea water. Metallic iron, along with minor proportions sulphide magnetite was detected laboratory sample...

A unique association between bacterial cells and small goethite particles (approximately 0.2 by 2 microm) protected Escherichia coli and Pseudomonas putida from UV inactivation. The protection increased with the particle concentration in the turbidity range of 1 to 50 nephelometric turbidity units and with the bacterium-particle attachment time prior to UV irradiation. The lower degree of bacte...

Despite obvious differences in morphology, substratum chemistry and the electrolyte in which they form, accumulations of iron corrosion products have the following characteristics in common: stratification of iron oxides/hydroxides with a preponderance of α-FeOOH (goethite) and accumulation of metals. Bacteria, particularly iron-oxidizing and sulfate-reducing bacteria have been identified in so...

By use of Mössbauer spectroscopy we have studied the magnetic properties of samples of goethite nanoparticles with different particle size. The spectra are influenced by fluctuations of the magnetization directions, but the size dependence is not in accordance with the Néel-Brown expression for superparamagnetic relaxation of the magnetization vectors of the particles as a whole. The data sugge...