Porphyry (dacite or rhyolite) (CTPp;0)

State	Connecticut
Name	Porphyry (dacite or rhyolite)
Geologic age	Permian
Original map label	Pp
Comments	Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium
Primary rock type	rhyolite
Secondary rock type	dacite
Other rock types
Lithologic constituents	Major Igneous > Volcanic > Felsic-volcanic > RhyolitePorphyry (dacite or rhyolite) - Light-colored, very fine grained, massive porphyry with phenocrysts of quartz, feldspar, and biotite; muscovite and accessory fluorite in groundmass. Igneous > Volcanic > Felsic-volcanic > DacitePorphyry (dacite or rhyolite) - Light-colored, very fine grained, massive porphyry with phenocrysts of quartz, feldspar, and biotite; muscovite and accessory fluorite in groundmass.
Map references	Connecticut Geological and Natural History Survey, DEP, in cooperation with the U.S. Geological Survey, 2000, Bedrock Geology of Connecticut, data format: shapefile, file name: bedrock, downloaded from: http://magic.lib.uconn.edu/cgi-bin/MAGIC_DBsearch2.pl?Geography=37800&Loc=0000 on 9/18/2003, scale 1:50,000. [http://magic.lib.uconn.edu/connecticut_data.html#environmental] [http://magic.lib.uconn.edu/cgi-bin/MAGIC_DBsearch2.pl?Geography=37800&Loc=0000]
Unit references	Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 125,000.
Geographic coverage	Fairfield