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U.S. Geological Survey Open-File Report 03-221
A Pictorial Survey of the Bedrock Beneath Western Cape Cod, Massachusetts

 Detailed Bedrock Photographskip navbar


SAMPLE_ID:  03MW0110

DATE: 6/2/1998

Sample: 03MW0110 - Granitoid


A granite with an ultramylonite, sample 03MW0110 is composed of K-feldspar (40%), plagioclase (35%), quartz (20%), chlorite (3%), epidote (1%), and trace muscovite, sphene, and oxides. This sample is characterized by an ultramylonite zone where differential strain is concentrated in an otherwise unfoliated granite. Feldspar porphyries in the granite are severely seritized and show perthite and antiperthite. Large aggregates quartz in the matrix show interlocking grains. Chlorite may have replace biotite and other mafics, and occurs commonly in bundles. The ultramylonite is composed small, 0.5 mm porphyries of K-feldspar, quartz, sphene, plagioclase and epidote in a matrix of fine-grained quartz, epidote, and chlorite. It is approximately 10 mm thick. 

Latitude: 41.65272

Longitude: -70.54819

Elevation of well site (m): 35.14

Elevation of the upper
bedrock surface (m):

Elevation of the
top of casing (m):

Total thickness of strata
penetrated by the well (m):

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