A coarse-grained tonalite, sample 95MW0207 contains
plagioclase (57%), quartz (40%), muscovite (2%), K-feldspar (1%), and
trace oxides. Seritized plagioclase shows a range of grain sizes, though
grains reach 9 mm. Plagioclase is albite and carlsbad twinned and shows
interlocking grain boundaries. Serrated quartz grains exhibiting
undulose extinction and subgrain development commonly fill "gaps"
between large plagioclase phenocrysts. Muscovite rims plagioclase and in
some places replaces plagioclase along twin planes. K-feldspar, a very
minor constituent of this rock, is partially altered and fills gaps
between plagioclase porphyries.