Oxidation During Magmatic Differentiation, Finnmarka Complex, Oslo Area, Norway: Part 2, The Mafic Silicates1

Biotite from Čierna hora Mountains granitoids (Western Carpathians, Slovakia) and estimation of water contents in granitoid melts

“…The activity of K-feldspar is 0.6 for magmatic temperatures (Czamanske & Wones 1973) and activity of most re-equilibrated magnetites is close to 1. The f H 2 O then can be calculated from (2, 3) for a series of temperatures.…”

“…The importance of granitoid biotite rests in its assemblage with K-feldspar and magnetite, which acts as a buffer of oxygen and water fugacities in the magma (Wones & Eugster 1965;Czamanske & Wones 1973 in the magma (best through coexisting Fe-Ti oxides, which may provide precise estimates of both oxygen fugacity and temperature) and activities of magnetite and K-feldspar with (Wones & Eugster 1965). Symbols are the same as in Fig.…”

“…This is based on the observation that biotite in succession always comes after An-rich plagioclase cores and coexists with albite enriched rims. some certainty, the activity of annite in biotite may be used to derive the water fugacity through the reaction (Wones 1972;Czamanske & Wones 1973 (Mueller 1972;Wones 1972), (Bohlen et al 1980, X 0 refers to pure annite), (Holland & Powell 1990), a ann =(X Fe 2+) 3 (X K )(X OH ) 2 (Nash 1993),…”

Geochemistry of the Rio Espinharas hybrid complex, northeastern Brazil

“…However, in general, no relationship was found between crystallographic orientation and chemical composition, because most amphibole crystals are heterogeneous (e.g., Robinson et al, 1971;Droop, 1994). Amphibole crystals show patch domains enriched in Mg, which may reflect the adjustment of amphibole to magmatic changes (e.g., Czamanske and Wones, 1973), but it is probably the result of near-solidus deformation and consequent partial reequilibration. Linear trends are found (Fig.…”

Pyroxenes and coexisting minerals in the Cheviot granite

“…In conformity with the usual partition relationships, A1 and Cr are higher and Mn is lower in the magnetites than in the ilmenites. MnO in ilmenite reaches 5.3 ~ in CH3 and 2.3~o in CH5, much lower than the 10-20~o in the granodiorite at Finnmarka, which has a broadly similar whole-rock composition (Czamanske, 1965;Czamanske and Mihalik, 1972).…”