A fine-grained granite, sample 81MW0004 contains
quartz (40%), plagioclase (29%), K-feldspar (29%), muscovite (1%), and
trace biotite, chlorite, and oxides. Quartz occurs in elongated
aggregates and shows interlocking grains, variable grain size, subgrain
development, and undulose extinction. Plagioclase and K-feldspar both
also occur in elongated aggregates. Plagioclase is albite twinned and
seritized. K-feldspar is perthitic and embayed by quartz grains.
Muscovite is not generally aligned in the foliation, and commonly occurs
near oxides. Biotite, in the proximity of oxides, is partially replaced
by chlorite. A foliation is defined by the preferred orientation of
elongated aggregates of quartz, K-feldspar, and plagioclase, and not by
micas. |