Mineralogical changes

Figure 1.14. Schematic diagram showing mineralogical changes in various kinds of ores of Kuroko deposits (Matsukuma and Horikoshi, 1970).

GER analysis incorporating element combinations designed to reflect the main minerals of the unaltered, altered and weathered rocks reveals clear separation of these different compositions and explains the mineralogical changes during alteration (Fig. 4). Unaltered shale compositions cluster toward the muscovite/ankerite node of the... 

Hydrothermal alteration associated with the formation of the Elura deposit has produced visible mineralogical changes in... 

It is important to note two things in this analysis first, the reactions which govern silicate phase equilibria occur in a system closed to large-scale chemical migration. This corresponds to a pore-water sediment system of local equilibrium. Second, the most striking mineralogical change—the crystallization of feldspar—is, in fact, the result of the instability of another phase, montmorillonite. The use of... 

In a warm and semi-arid climate thick calcretes can develop. Alteration in the vadose zone is relatively rapid but not as rapid as in the phreatic zone. Surface karst is present locally, and caves are small and rare. The mineralogical changes follow the pattern of Figure 7.25, but at a rate slower than that for a warm, subtropical climate like Bermuda. Under the extreme of a warm, wet tropical climate, extensive terra-rossa soils can develop, and dissolution features, such as caves, solution pipes and fractures, should be prevalent. Mineralogical stabilization should occur rapidly. 

Zelazny, L. W., D. A. Leitzke, and H. L. Barwood. 1980. Septic tank drainfield failure resulting from mineralogical changes. Va. Water Resour. Res. Center, Bull. 129 118. 

Figure 29 X-ray maps of Mn, Ca, Fe/(Fe + Mg) ( FM ), Cr, and Sc in garnets from Fall Mountain, New Hampshire. White box indicates area of major element maps. Different generations of growth can be linked to prograde reaction history, to better understand mineralogical changes attending metamorphism and anatexis, and overall P-T evolution. Black line shows location of composition traverse plotted in Figure 30...

Figure 11. Mineralogical changes during firing of the marl SD 28 and the volcanic noncalcareous clays SD 47 and SD 48.

Figure 13. Combined scheme showing the mineralogic changes in firing of both mixtures as deduced from optical microscopy (matrix + amphibole + pyroxene) and x-ray diffraction analysis (montmoril-...

Schumacher (1996) contended that long-term leakage of hydrocarbons can establish locally-anomalous redox zones that favour the development of a diverse array of chemical and mineralogical changes. The bacterial oxidation of light hydrocarbons can... 

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