The American Journal of Science, Band 288

alkali amphibole amphibole amphibolite analyses Archean biotite calculated Carpenter Ridge Catheart Mountain cations Chain Lakes Massif chemical chlorite Coast batholith coexisting cordierite core crust crystallization Devonian Devonian plutons Eagle Peak pluton equilibrium Fe³ feldspar fiamme figure fluid fractionation garnet Geology gneiss grains granite granodiorite H₂O Hardwick Tonalite hornblende hornblende-biotite tonalite igneous ilmenite isotopic isotopic compositions Jour K-feldspar K₂O lead isotopic mafic magma magnetite mantle melting metamorphic mica Mineralogy modal muscovite northern Maine plutons octahedral oxides oxygen Penobscot Intrusive Suite peralkaline phase phenocrysts plagioclase plot plutons polyhedral porphyry pre-Devonian Proterozoic pyrite pyroxene pyrrhotite quartz diorite range ratios reaction samples schists Sierra Nevada silicates SiO2 South Penobscot Intrusive sphene structure sulfidic tectonic temperature tetrahedral tetrasilicic mica thermal tion tonalite trace element Tuff U.S. Geol values variation volcanic Whole rock Wones wt percent xenoliths zone