Devonian - Precambrian Z Gonic Formation

Devonian - Precambrian Z Gonic Formation
State Maine
Name Devonian - Precambrian Z Gonic Formation
Geologic age Devonian - Precambrian Z
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Phyllite (Greenschist, Amphibolite epidote-amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; Protolith A - Pelite
Metamorphic > Schist (Greenschist, Amphibolite epidote-amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; Protolith A - Pelite
Comments Named for Appleton Ridge in Knox and Waldo Cos, ME. Previously called Appleton formation (informal) by Cheney (1967). Consists of lower andalusite zone (staurolite schist), garnet zone (phyllite with minor garnet), and the Muzzy Ridge Member (cummingtonite-garnet schist). Bedded and sheared. 1,200 m thick. Conformably overlies Bucksport Formation; in fault contact with Jam Brook Formation to the southwest and Penobscot Formation to the northeast along St. George fault. (ME035) Unit description from USGS GEOLEX 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.
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.

US Geological Survey, 2005, National Geologic Map Database, Geologic Names Lexicon "GEOLEX", http://ngmdb.usgs.gov/Geolex/.

NGMDB product
Counties York