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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

81MW0004

SAMPLE_ID:  81MW0004

DATE: 2/7/2001

Sample: 81MW0004 - Granite

GRANITE

A fine-grained granite, sample 81MW0004 contains quartz (40%), plagioclase (29%), K-feldspar (29%), muscovite (1%), and trace biotite, chlorite, and oxides. Quartz occurs in elongated aggregates and shows interlocking grains, variable grain size, subgrain development, and undulose extinction. Plagioclase and K-feldspar both also occur in elongated aggregates. Plagioclase is albite twinned and seritized. K-feldspar is perthitic and embayed by quartz grains. Muscovite is not generally aligned in the foliation, and commonly occurs near oxides. Biotite, in the proximity of oxides, is partially replaced by chlorite. A foliation is defined by the preferred orientation of elongated aggregates of quartz, K-feldspar, and plagioclase, and not by micas.

Latitude: 41.64338

Longitude: -70.56448

Elevation of well site (m): 29.03

Elevation of the upper
bedrock surface (m):
-52.97

Elevation of the
top of casing (m):
 28.93

Total thickness of strata
penetrated by the well (m):
 83.82

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