Composition of minerals

Mineralstoff, m. mineral substance, mineral matter, -gehalt, m. mineral content, -wech-self m. mineral (or inorganic) metabolism, -zusammensetztmg,/. composition of mineral matter. 

Many studies have been made of the rates of water evolution from layer-type silicate minerals which contain structural hydroxyl groups (clays and micas). Variations in composition of mineral specimens from different sources hinders comparison of the results of different workers. Furthermore, the small crystallite sizes and poor crystallinity that are features of clays limit and sometimes prevent the collection of ancillary observations (e.g. microscopic examination and diffraction measurements). 

Isotopic compositions of minerals and fluid inclusions can be used to estimate those of Kuroko ore fluids. Estimated isotopic compositions of Kuroko ore fluids are given in Table 1.10. All these data indicate that the isotopic compositions lie between seawater value and igneous value. For instance, Sr/ Sr of ore fluids responsible for barite and anhydrite precipitations is 0.7069-0.7087, and 0.7082-0.7087, respectively which are between present-day. seawater value (0.7091) and igneous value (0.704-0.705). From these data, Shikazono et al. (1983), Farrell and Holland (1983) and Kusakabe and Chiba (1983) thought that barite and anhydrite precipitated by the mixing of hydrothermal solution with low Sr/ Sr and seawater with high Sr/ Sr. 

Table 5.17. Molar chemical composition of minerals in the assemblage quartz (qz)- muscovite (ms)- K-feldspar (Kf)-sillimanite (sil) - water (w).

Table 5.19. Molar chemical composition of mineral end-members in the assemblage of Table 5.18. See text for abbreviations.

Figure 10. Lithium isotopic compositions of minerals from the Tin Mountain pegmatite. Black Hills, South Dakota (Tomascak et al. 1999c). Differences in the equilihrium quartz-feldspar oxygen isotopic compositions between the wall zone and intermediate zones suggested temperatures of 600 to 550°C (Walker et al. 1986). Despite poor precision of these data, they showed a consistent increase in the A Li, ,. between the early-crystallizing wall zone and the later-crystallizing core.

For definitions of units, chemical composition of minerals, chemical formulae of molecules and time spans of geologic periods, see the Appendices. 

The distributions of trace elements between minerals and within a suite of related rocks provide powerful tools for constraining the origin and history of rocks and meteorites. Trace-element abundances for rocks typically are part of the data set collected when determining bulk compositions. Trace element compositions of minerals require more powerful techniques such as the ion microprobe or the laser-ablation inductively coupled plasma mass spectrometer (ICPMS). 

Oxygen isotopic compositions of minerals in CAIs on an oxygen three-isotope diagram. Axes are given in delta notation 81S0 =[((180/160)sampie/(180/160)s,andard)-1] x 1000, and similarly for S170. After Clayton et al. (1977). 

Hardness determination methods find wide uses in basic research on the mechanical properties of minerals and their deformation. In the face of the rapid development of industrial uses of natural minerals, as well as manmade, in monocrystal or grain form or as polymineral materials, there is a definite need for more comprehensive crystallomechanical investigations. Apart from the above aspects, hardness determination should furnish valuable information on the genesis of minerals. These authors consider that it would well serve the purpose to examine the mechanical properties of all minerals so as to obtain their allround crystallomechanical characterization and to investigate into their anisotropy and relationship to the structure and composition of minerals. By determining the typomorphism of the mechanical parameters of minerals and its involvement in the conditions of their formation, and also by investigating the specificity of occurrence of deformations in minerals under natural conditions and of the deformative mechanism, it should be possible to develop a general theory of mechanical properties of crystals. 

Fig. 5.16. Relationship between hardness and composition of minerals on the example of (a)—isomorphous gold-silver bond order, (b)—galena PbS, according to silver content. (After Yushkin, 1971)...

Table I. Approximate Chemical Composition of Minerals Discussed...

A solution to the problem of determining the composition of mineral oil fractions, especially those of high molecular weight, is provided by dealing with the oil fractions in a statistical way, i.e. some characteristic structural elements in the mixture are defined and determined by appropriate means. 

More detailed knowledge of the composition of mineral oils can be obtained by splitting the oils into as narrow fractions as possible by means of fractionation, thermodiffusion, chromatography, extraction and other means. On the opposite page a scheme is given as an illustration of the application of distillation techniques in the investigation of mineral oils and polymerized fatty oils. 

When the problem of establishing the structure of hydrogenated products has been solved, more complicated mixtures, e.g. aromatic-containing fractions, can be considered. The existing methods of determining the composition of mineral oil fractions have been developed according to this scheme. The methods presented below are treated in principle in chronological order. 

In the n-d-M method use is made of three physical constants, namely the refractive index n (measured for the sodium D-line), the density d in g/ml and the molecular weight M, for the determination of the composition of mineral oil fractions. 

In the last few years the kinematic viscosity and its temperature dependence have been used for the determination of the composition of mineral oil fractions. The first steps in this field were made by Boelhouwer, Van Steenis and Waterman13, who... 

The cross-sections can be used for the determination of the carbon-type composition of mineral oil fractions in the following way. 

It should be remarked, that in several respects fatty oils and related products usually have a far less complicated character than have mineral oil products. The number of fatty acids occurring in natural fats is limited and certain structural elements, which contribute considerably to the composition of mineral oi s (cyclic compounds, branchings) hardly occur. On the other hand, phenomena such as cis-trans isomerism, al-... 

Source Reprinted from Schulten, H.-R., and Leinweber, P. (1999). Thermal stability and composition of mineral-bound organic matter in density fractions of soil. European Journal of Soil Science 50,237-248, with permission from Blackwell. 

This list is organized according to the chemical composition of mineral species. The simplest, the native elements, are first, followed by progressively more complex minerals. This list only includes those species that are used as gems or ornamental materials. Organic substances, such as amber and jet, are not included and will be addressed elsewhere. 

Gat, J.R., Mazor, E., and Tzur, Y. (1969) The stable isotope composition of mineral waters in the Jordan Rift Valley, Israel. J. of Hydrology 7, 334-352. 

In the isomorphous replaceability of corresponding elements in the composition of minerals, a very widely occurring phenomenon especially in the silicates, it is not the charge but the radius which has the decisive significance. Thus the following replacements occur, for example ... 

Figure 9 Oxygen-isotopic compositions of minerals in the Efremovka CAIE104 (a) and Vigarano CAI1623-2 (b) and their forsterite-rich accretionary rims (AR) and Wark-Lovering rims (WLR) showing that both formed in an 0-rich reservoir (after Krot et al, 2002b).

Four cratonic, ultradeep xenoliths from S. Africa and Sierra Leone have been analyzed for their strontium and neodymium isotopic compositions (Macdougall and Haggerty, 1999). The neodymium isotopic compositions of minerals from these xenoliths suggest that they were emplaced into the African lithosphere at times ranging from approximately the time of kimberlite emption to hundreds of millions of years earlier. The samples show a complex history of melt... 

Glaser S. M., Foley S. F., and Gunther D. (1999) Trace element compositions of minerals in garnet and spinel peridotite xenoliths from the Vitim volcanic field, Transbaikalia, eastern Siberia. Lithos 48, 263 —285. 

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