Sample 82MW0006 is an unfoliated granodiorite with
a composition of plagioclase (48%), quartz (25%), K-feldspar (11%),
biotite (8%), chlorite (4%), sericite (2%), epidote (1%), and trace
sphene and oxides. Plagioclase is extremely seritized/sausseritized.
Porphyries are commonly albite twinned, tabular, and rimmed by biotite.
Quartz shows an interlocking texture and slight undulose extinction and
subgrain development. K-feldspars are somewhat altered, perthitic, and
seem to replace plagioclase in some places. Biotite is
orange-green-brown pleochroic, and occurs as irregularly shaped grains
filling between plagioclase crystals. Chloritization is common in all
biotite, and some has been completely replaced. Fractures in this rock
are filled by calcite and opaque minerals. |