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Silurian rocks of the Fivemile Brook sequence

Silurian rocks of the Fivemile Brook sequence
State Maine
Name Silurian rocks of the Fivemile Brook sequence
Geologic age Silurian
Comments The preliminary discussion in Roy (1980) is here revised. The Fivemile Brook Formation consists of light-greenish-gray calcareous phyllite with thin beds and lenses of argillaceous biomicritic limestone and four mappable sequences of basaltic lava. (ME037) Unit description from USGS GEOLEX website (ME078). W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith B - Calcareous pelite
Primary rock type phyllite
Secondary rock type limestone
Other rock types basalt
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Phyllite (Calcareous)W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith B - Calcareous pelite
Minor
Sedimentary > Carbonate > LimestoneW - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith B - Calcareous pelite
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith B - Calcareous pelite
Map references
Digital bedrock data downloaded from Maine Office of GIS in September 2005 from http://apollo.ogis.state.me.us/catalog/catalog.asp?state=2&extent=cover#bedrock Bedrock units table (publication date 11/15/2002) downloaded from same site. Permission to redistribute these data granted by Dr. Robert Marvinney, State Geologist of Maine, in September 2006.
Unit references
Osberg, P. H., Hussey, A.M., and Boone, G. M., 1985, Bedrock geologic map of Maine: Maine Geological Survey, Dept. of Conserv., scale 1:500,000.
Boudette, E.L., Hatch, N.L., Jr., and Harwood, D.S., 1976, Reconnaissance geology of the Upper St. John and Allagash river basins, Maine: U.S. Geol. Surv., Bull. 1406, 37 p.
Roy, D.C. and Lowell, T.V., 1983, Bedrock and surficial geology of the upper St. John River area, northwestern Aroostook County, Maine; Field trip 5, IN Hussey, A.M., II, and Westerman, D.S., eds., Field trips of the Geological Society of Maine, 1978-1983: Maine Geology Bulletin, no. 3, p. 26-49.
USGS Geologic Names Lexicon (GEOLEX)
Counties Aroostook