Muscovite elements

Key indicators of alteration and proximity to ore are increased K2O (particularly in the shale component) near complete loss of Na20 increased FeO (particularly in the siltstone-sandstone component) and increased CO2 in shale. These changes reflect the development of iron carbonate (siderite and ankerite) by carbonate introduction and some alteration of existing calcic carbonate in siltstone-sandstone samples. Destruction of albite, absence of chlorite and increased abundance of muscovite due to potassic alteration, are the other major mineral alteration effects in the altered host rocks. Trace elements enriched in the primary dispersion zone are Zn, Pb, Ag, Sb, As, Rb, and TI. Antimony provides the most consistent and extensive trace element dispersion halo around the deposit and is also preserved in most of... 

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... 

Dahl, P. S., Wehn, D. C. Feldman, S. G. (1993) The systematics of trace-element partitioning between coexisting muscovite and biotite in pelitic schists from the Black Hills, South Dakota. Geochim. Cosmochim. Acta, 57, (in press). 

Icenhower J. and London D. (1995) An experimental sffidy of element partitioning among biotite muscovite and coexisting... 

Phlogopite is found in metamorphosed magnesium-rich limestones, dolomites, and ultrabasic rocks. Biotite, similar to muscovite, is also widespread. It is usually associated with minerals which were formed under high temperature and pressure. Several elements, other than those included in their typical chemical composition, can be found in these two minerals. These include Na, Rb, Cs, Ba, F, and Ca. The most important difference between phlogopite and biotite is that biotite contains a substantial amount of iron. 

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