Ordovician - Cambrian Dead River Formation, upper member

Ordovician - Cambrian Dead River formation upper member
State Maine
Name Ordovician - Cambrian Dead River Formation, upper member
Geologic age Ordovician - Cambrian
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Phyllite (Amphibolite epidote-amphibolite, Greenschist, Zeolitic (prehnite-pumpellyite))Protolith E - Feldspathic sandstone; E - Epidote-amphibolite facies; GS - Greenschist facies; W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite.
Metamorphic > Metasedimentary > Metaclastic > Quartzite (Amphibolite epidote-amphibolite, Greenschist, Zeolitic (prehnite-pumpellyite))Protolith E - Feldspathic sandstone; E - Epidote-amphibolite facies; GS - Greenschist facies; W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite.
Comments Dead River Formation of Bronson Hill-Boundary Mountains anticlinorium was previously mapped as Albee Formation in Cupsuptic 15-min quad by Harwood (1973) and in Oquossoc 15-min quad by Guidotti (1977) in ME and in wide areas of northern NH by Billings (1956) and Green (1968). In Cupsuptic quad, consists of a main body of thinly interbedded greenish-gray slate and typically subordinate quartzite or feldspathic quartzite. Unit is also divided into three parts not shown on this map--a main body, a green slate and phyllite member, and a red, maroon, and purplish-gray slate member. A quartzite-rich member is mapped separately in Kennebago Lake 15-min quad, ME, and further east. An unnamed quartzite and phyllite member at Percy, in Percy, NH, 15-min quad, is mapped separately and consists of quartzite and grit interbedded with phyllite; possibly a volcaniclastic facies of Perry Mountain Formation. Dead River Formation is undated, but is assigned a Late Cambrian(?) and Ordovician (Whiterockian) age based on position below Ordovician (Whiterockian and Mohawkian) Ammonoosuc Volcanics and above Cambrian(?) Hurricane Mountain Formation. (ME004) Unit description from USGS GEOLEX website (ME078). AB - Medium rank amphibolite facies; E - Epidote-amphibolite 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.

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

NGMDB product
Counties Franklin - Oxford - Piscataquis - Somerset