The purpose of this study is to understand mineral diagenesis authigenic mineral and the effect of climate on mineral of Pleistocene-Holocene sediment deposits in the Southern Kenya Rift. Lake Magadi unique geologic settings are characterized by extreme alkalinity and high silica activities. The mineralogical analysis was achieved by X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM...

Introduction: Basaltic shergottite Queen Alexandra Range 94201 originated from an extremely depleted mantle source, and has the highest initial εNd (+ 47.6 ± 1.7) and the lowest initial Sr/Sr (0.701298 ± 14) measured for any martian meteorite to date [1]. Rb-Sr and Sm-Nd isochrons for this sample yield concordant crystallization ages of 327 ± 12 Ma and 327 ± 19 Ma, respectively [1]. Knowledge o...

Mineral weathering in soils is an important source of many nutrients to forest ecosystems. Apatite, a Ca phosphate mineral, occurs in trace amounts in virtually all igneous and metamorphic rocks and is often found as small mineral inclusions in more weathering-resistant silicate minerals. To better understand the distribution of apatite in soils and its exposure to soil solutions, a sequential ...

The influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P)...

Combined annealing experiments and observations by transmission electron microscopy show that in natural pigeonite crystals antiphase domains coarsen approximately according to a rate law in which the tenth power of the average domain size is proportional to time. This result suggests that certain cations (possibly Ca(2+)) were segregated preferentially onto the antiphase boundaries. The domain...

Mineral Compositions in Xenoliths from Malaita The report by Collerson et al. (1) of transition zone and lower mantle phases in mantle-derived material from alnöite pipes on Malaita, Solomon Islands, is highly significant in view of the rarity of such natural assemblages. Malaita is part of the obducted southern margin of the Ontong Java Plateau, an area of overthickened oceanic crust (2–7) tha...

marbles containing high-pressure mineral assemblage was found from the sanandaj-sirjan metamorphic belt in the nahavand area in western iran.  the high-pressure marbles occur as small bodies or lenses within pelitic schist layers and show compositional banding of carbonate- and silicate- rich bands.  textural analysis revealed two metamorphic stages.  the early stage is testified by relicts of ...

Copyright © 2014 by The Geochemical Society of Japan. Strandh et al., 1997), reactivity of different surface sites (e.g., Blum and Lasaga, 1988, 1991; Blum et al., 1990; Dove, 1994; Furrer and Stumm, 1986; Lasaga, 1992; Pelmenschikov et al., 2000; Raghavachari and Rohlfing, 1991; Bickmore et al., 2008; Wallace et al., 2010), the extent of undersaturation of the solution (e.g., Dove et al., 2005...

Aim: Calcium silicate-based materials are hydraulic self-setting materials with physico-chemical properties suitable for endodontic surgery and good biological/clinical outcomes. The study aim was to evaluate the bio-properties (biointeractivity and apatite-forming ability) and selected physical properties (porosity, water sorption, solubility, and setting time) of Biodentine, a tricalcium sili...