Silurian Sangerville Formation Anasagunticook member (MESsa;0)

State	Maine
Name	Silurian Sangerville Formation Anasagunticook member
Geologic age	Silurian
Original map label	Ssa
Comments	Consists of well-bedded metasandstone, thinly laminated metasiltstone, and metashale. Thin medial unit of metalimestone. Thought to be fine-grained facies of Sangerville Formation and is assigned as a member (after usage of Pankiwskyj, 1979). About 1,000 m thick. Gradationally overlies Patch Mountain Member of Sangerville Formation. (ME041). Anasagunticook Member reassigned from Sangerville Formation to Waterville Formation following usage of Osberg (1988). Not shown separately on this map to simplify nomenclature. Rocks previously mapped as Anasagunticook Member of Sangerville Formation in the Bryant Pond, Buckfield, Dixfield, and Farmington 15-min quads are here shown as Waterville Formation (queried). Anasagunticook correlated with Waterville by Osberg (1988) on the basis of lithologic similarity. (ME004) Unit description from USGS GEOLEX website (ME078). GS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone
Primary rock type	metasedimentary rock
Secondary rock type	marble
Other rock types
Lithologic constituents	Major Metamorphic > Metasedimentary > Metaclastic > MetasandstoneGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone Minor Metamorphic > Metasedimentary > Metacarbonate > MarbleGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone Metamorphic > Metasedimentary > Metaclastic > SlateGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone Metamorphic > Metasedimentary > Metaclastic > MetasiltstoneGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone
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. Moench, R.H., Boone, G.M., Bothner, W.A., Boudette, E.L., Hatch, N.L., Jr., Hussey, A.M., III, Marvinney, R.G. and Aleinikoff, J.N., 1995, Geologic map of the Sherbrooke-Lewiston area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada: U.S. Geological Survey Miscellaneous Investigations Series Map, I-1898-D, 56 p., 2 sheets, scale 1:250,000, Prepared in cooperation with the Maine Geological Survey and the New Hampshire Geological Survey. [http://pubs.er.usgs.gov/publication/i1898D] Moench, R.H. and Pankiwskyj, K.A., 1988, Geologic map of western interior Maine: U.S. Geological Survey Miscellaneous Investigations Series Map, I-1692, 21 p., 1 sheet, scale 1:250,000. [http://pubs.er.usgs.gov/publication/i1692] USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Androscoggin - Franklin - Oxford - Somerset