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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:  80MW0003

DATE: 4/5/2001

Sample: 80MW0003 - Basalt


Sample 80MW0003 is an olivine phyric basalt containing plagioclase (60%), clinopyroxene (20%), chlorite (15%), and oxides (5%). Extreme chloritization has taken place in this rock, completely replacing olivine. Chloritization of calcite veins suggests that vein development occurred before some, if not all alteration. Relict laths of plagioclase are visible, yet plagioclase itself is turgid beyond recognition. Subhedral fine-grained oxides are present throughout. Chlorite percentage estimate may be low, as an unrecognizable amount of chlorite also occurs in the matrix, replacing other minerals.

Latitude: 41.63067

Longitude: -70.58921

Elevation of well site (m): 30.69

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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