An orthogneiss, sample 81MW0016 contains K-feldspar
(40%), plagioclase (35%), quartz (21%), chlorite (2%), oxides (1%), and
trace muscovite, sphene, and epidote. Perthitic K-feldspar, occurring in
the matrix and as porphyroclasts, shows subgrains, tartan twinning, and
inclusions of quartz and plagioclase. Any biotite present has been
totally altered to chlorite. A foliation is present, defined by chlorite
and elongated quartz aggregates.