Cambrian Grand Pitch Formation

Cambrian Grand Pitch Formation
State Maine
Name Cambrian Grand Pitch Formation
Geologic age Cambrian
Lithologic constituents
Major
Sedimentary > Clastic > MudstoneProtolith Q - Interbedded pelite and sandstone; W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Also GS - Greenschist facies
Sedimentary > Clastic > SandstoneProtolith Q - Interbedded pelite and sandstone; W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Also GS - Greenschist facies
Comments Named for Grand Pitch of East Branch of Penobscot River. Penobscot Co., northeastern ME. Name replaces Grand Falls Formation of Ruedemann and Smith (1935); name was preoccupied. Continuous exposure lines riverbanks for 1000 ft in vicinity of Grand Pitch. At type section, consists of light-greenish-gray, fine-grained quartzite in massive beds interbedded with thinner layers of light-greenish-gray and medium gray slate; and red slate containing OLDHAMIA SMITHI Ruedemann. Proportions of slate increase both upstream and downstream. (ME073) Unit description from USGS GEOLEX website (ME078). W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Protolith Q - Interbedded pelite and sandstone; Also GS - Greenschist facies; Protolith Q - Interbedded pelite and sandstone.
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.

Neuman, R.B., 1967, Bedrock geology of the Shin Pond and Stacyville quadrangles, Penobscot County, Maine, IN Shorter contributions to general geology, 1965: U.S. Geological Survey Professional Paper, 524-I, p. I1-I39.

https://pubs.er.usgs.gov/publication/pp524I

Neuman, R.B., 1962, The Grand Pitch Formation; new name for the Grand Falls Formation (Cambrian?) in northeastern Maine: American Journal of Science, v. 260, no. 10, p. 794-797.

Rankin, D.W., 1994, Continental margin of the eastern United States; past and present, IN Speed, R.C., ed., Phanerozoic evolution of North American continent-ocean transitions: Geological Society of America, The Decade of North American Geology (DNAG), Continent-Ocean Transect Series, p. 129-218.

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

NGMDB product
Counties Aroostook - Penobscot