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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:  69MW1518

DATE: 8/15/2000

Sample: 69mw1518 - Granite


A biotite granite, sample 69MW1518 has a composition of plagioclase (35%), K-feldspar (30%), quartz (20%), biotite (10%), sericite (3%), sphene (1%), and trace hornblende, muscovite, chlorite, oxides, and epidote. Seritized plagioclase porphyries (up to 7 mm), show albite twinning. K-feldspar porphyries exhibit undulose extinction, minor perthite, carlsbad and tartan twinning, and plagioclase inclusions. Quartz occurs as recrystallized grains with 120 grain boundaries in mm-thick equigranular domains. Biotite occurs in clusters with no preferred orientation, and is in some places replaced by chlorite. Hornblende is deep brown and rimmed by epidote, plagioclase and biotite. Sphene occurs as subhedral, rhomb-shaped grains that are visible in hand sample. No fabric is recognized in this granite.

Latitude: 41.64418

Longitude: -70.57265

Elevation of well site (m): 35.85

Elevation of the upper
bedrock surface (m):

Elevation of the
top of casing (m):

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

Zip file with full resolution image. skip navbar

OFR03-221 Home | Introduction | Bedrock Photographs | GIS Data Catalog

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