Dataset Identification:
Resource Abstract:
- description: Cores collected from recent drilling in western Cape Cod, Massachusetts provide insight into the topography and
petrology of the underlying bedrock. Cores from 64 drill sites spread over a approximately 140 km2 study area produced samples
of granitoids (31), orthogneisses (20), basalts/diabases (4), amphibolites (3), felsic mylonites (2), and dolomitic rock (2).
Granitoid composition ranges from granite to tonalite and quartz diorite, but it is dominated by two-feldspar granites. Hydrothermal
alteration is common in nearly all cores as evidenced by the secondary growth of chlorite and epidote. Granitoids resemble
rocks of the Dedham and Fall River plutons (Wones and Goldsmith, 1991). Gneisses generally contain the mineral assemblage
K-feldspar+plagioclase+quartz+/-biotite+/- chlorite+/-muscovite+/-sphene+/-epidote+oxides. Amphibolites contain the assemblage
hornblende+plagioclase+quartz+biotite+epidote+/-chlorite+/-sphen+/-K-feldspar+/-sericite+ oxides. Peak metamorphic grade based
on mineral assemblages is estimated at lower amphibolite facies. X-ray powder diffraction of unmetamorphosed dolomitic cores
shows presence of layered silicates (clays), plagioclase, and possible magnesite. Contours of the bedrock surface show locally
irregular topography suggesting erosion by glacial scour. Lithologic distribution mapping suggests a possible continuation
of the New Bedford gneissic terrane that outcrops 25 km to the west. Dolomitic rocks may represent a lithified fault gauge
material at the eastern edge of the gneissic zone. Basalts/diabases are interpreted to be post-metamorphic dikes associated
with Mesozoic rifting.; abstract: Cores collected from recent drilling in western Cape Cod, Massachusetts provide insight
into the topography and petrology of the underlying bedrock. Cores from 64 drill sites spread over a approximately 140 km2
study area produced samples of granitoids (31), orthogneisses (20), basalts/diabases (4), amphibolites (3), felsic mylonites
(2), and dolomitic rock (2). Granitoid composition ranges from granite to tonalite and quartz diorite, but it is dominated
by two-feldspar granites. Hydrothermal alteration is common in nearly all cores as evidenced by the secondary growth of chlorite
and epidote. Granitoids resemble rocks of the Dedham and Fall River plutons (Wones and Goldsmith, 1991). Gneisses generally
contain the mineral assemblage K-feldspar+plagioclase+quartz+/-biotite+/- chlorite+/-muscovite+/-sphene+/-epidote+oxides.
Amphibolites contain the assemblage hornblende+plagioclase+quartz+biotite+epidote+/-chlorite+/-sphen+/-K-feldspar+/-sericite+
oxides. Peak metamorphic grade based on mineral assemblages is estimated at lower amphibolite facies. X-ray powder diffraction
of unmetamorphosed dolomitic cores shows presence of layered silicates (clays), plagioclase, and possible magnesite. Contours
of the bedrock surface show locally irregular topography suggesting erosion by glacial scour. Lithologic distribution mapping
suggests a possible continuation of the New Bedford gneissic terrane that outcrops 25 km to the west. Dolomitic rocks may
represent a lithified fault gauge material at the eastern edge of the gneissic zone. Basalts/diabases are interpreted to be
post-metamorphic dikes associated with Mesozoic rifting.
Citation
- Title Bedrock Data from Western Cape Cod, Massachusetts (WELLSITE shapefile, Geographic, NAD27).
-
- creation Date
2018-05-21T10:43:49.226865
Resource language:
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Metadata data stamp:
2018-08-06T21:33:56Z
Resource Maintenance Information
- maintenance or update frequency:
- notes: This metadata record was generated by an xslt transformation from a dc metadata record; Transform by Stephen M. Richard, based
on a transform by Damian Ulbricht. Run on 2018-08-06T21:33:56Z
Metadata contact
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pointOfContact
- organisation Name
CINERGI Metadata catalog
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- Contact information
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- Address
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- electronic Mail Address cinergi@sdsc.edu
Metadata language
eng
Metadata character set encoding:
utf8
Metadata standard for this record:
ISO 19139 Geographic Information - Metadata - Implementation Specification
standard version:
2007
Metadata record identifier:
urn:dciso:metadataabout:1f86d98d-bca7-4d8d-9497-1bf8f4241be8
Metadata record format is ISO19139 XML (MD_Metadata)