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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:  82MW0002

DATE: 11/28/2000

Sample: 82MW0002 - Granodiorite


A granite, sample 82MW0002 contains K-feldspar (30%), plagioclase (30%), quartz (30%), chlorite (5%), sericite (2%), oxides (2%), and trace sphene and epidote. Perthitic, tartan and Carlsbad twinned K-feldspar porphyries show undulose extinction and irregular grain boundaries. Pinkish-tan plagioclase is heavily altered to epidote and sericite, and shows little twinning. Quartz grains exhibit serrated boundaries, subgrain development and undulose extinction. Large domains of chlorite/epidote/sphene are common as a "hash" of mafics/alteration products. Chlorite occurs in large (4-mm) aggregates, yet does not define a foliation. Fractures in this rock are filled with calcite and oxides.

Latitude: 41.64943

Longitude: -70.58092

Elevation of well site (m): 36.65

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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