Sample 03MW0109 is a quartz diorite with a
composition of plagioclase (63%), quartz (10%), biotite (10%),
muscovite/sericite (10%), K-feldspar (3%), epidote (2%), sphene (2%),
and oxides (1%). K-feldspar is very minor and may have been replaced
partly by plagioclase. Plagioclase has been severely altered to sericite
and eventually muscovite. Quartz grains show undulose extinction and
subgrains, suggesting some deformation. Biotite occurs in bundles around
sphene along with fine-grained epidote. |