A fine-grained orthogneiss, sample 69MW1603
contains K-feldspar (36%), quartz (31%), plagioclase (25%), and biotite
(8%). No oxides are present. K-feldspar grains are not perthitic and are
often found in bands with less plagioclase. The sample is almost
entirely recrystallized and nearly equigranular. Biotite defines a
strong foliation throughout. Plagioclase shows some myrmekitic
(intergrowths with quartz) textures and very minor alteration.