Devonian Carrabassett Formation (MEDc;0)

State	Maine
Name	Devonian Carrabassett Formation
Geologic age	Devonian
Original map label	Dc
Comments	Occurs in the Little Bigelow Mountain 15-min quad in the central Maine trough where it is separable in most places into an upper member of thinly interbedded metasandstone and gray pelitic schist (in about equal amounts), and a lower member of dark-gray, massive to faintly graded pelitic schist with local zones of cyclically interbedded pelitic schist and graded metasiltstone and sandstone. Neither the upper or lower members are mapped separately. An impure quartzite member (metasandstone and subordinate pelitic schist) and a black shale member (pelitic schist and subordinate metasiltstone or metasandstone) are mapped separately. In areas of migmatitic gneiss, Carrabassett and underlying Madrid Formation are not easily separated; some rocks mapped as Carrabassett contain abundant remnants of Madrid. Age is Early Devonian. Unit description from USGS Lexicon website (ME078). AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies E - Epidote-amphibolite facies GS - Greenschist facies Protolith A - Pelite
Primary rock type	schist
Secondary rock type	metasedimentary rock
Other rock types	gneiss
Lithologic constituents	Major Metamorphic > SchistProtolith A- Pelite AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies E - Epidote-amphibolite facies GS - Greenschist facies Minor Metamorphic > GneissProtolith A- Pelite AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies E - Epidote-amphibolite facies GS - Greenschist facies Metamorphic > Metasedimentary > Metaclastic > MetasiltstoneProtolith A- Pelite AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies E - Epidote-amphibolite facies GS - Greenschist facies Metamorphic > Metasedimentary > Metaclastic > MetasandstoneProtolith A- Pelite AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies E - Epidote-amphibolite facies GS - Greenschist facies
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. [http://apollo.ogis.state.me.us/catalog/catalog.asp?state=2&extent=cover#bedrock]
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. USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Franklin - Oxford - Penobscot - Piscataquis - Somerset