Orthogneiss 03mw2622

Bedrock sample from a UGSG drill core at Western Cape Cod, Massachusetts.
An orthogneiss with a composition of plagioclase (40%), K-feldspar (25%), quartz (25%), chlorite (5%), muscovite (2%), epidote (2%), and trace sphene and oxides, sample 03MW2622 shows less evidence of metamorphism than most of the other gneissic samples. 8-mm plagioclase porphyroclasts are visible in hand sample. Micas occur in 0.5-1 mm-thick bundles, yet no deformational fabrics are recognized.