Sample 69MW1707 is a gneiss containing an
assemblage of K-feldspar (35%), plagioclase (33%), quartz (30%), biotite
(2%), and trace muscovite and oxides. Large, perthitic K-feldspar
porphyroclasts are present throughout. Fine-grained, commonly
recrystallized quartz, plagioclase, and K-feldspar make up the matrix. A
foliation is defined by biotite. |