Silurian Sangerville Formation, Patch Mountain member

Silurian Sangerville Formation Patch Mountain member
State Maine
Name Silurian Sangerville Formation, Patch Mountain member
Geologic age Silurian
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metacarbonate > Marble (Greenschist, Amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; Protolith N - limestone and/or dolostone
Minor
Metamorphic > Schist (Greenschist, Amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; Protolith N - limestone and/or dolostone
Metamorphic > Metasedimentary > Calc-silicate-rock (Greenschist, Amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; Protolith N - limestone and/or dolostone
Metamorphic > Granoblastic > Granofels (Greenschist, Amphibolite)GS - Greenschist facies; E - Epidote-amphibolite facies; AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; Protolith N - limestone and/or dolostone
Comments In central Maine trough, Sangerville Formation is mapped as principal sandstone and shale facies, and subdivided into (ascending) Patch Mountain Limestone Member (name revised from Patch Mountain Member to emphasize lithology), consisting of thinly interbedded impure marble, coarsely crystallized calc-silicate rocks, granofels, and pelitic schist (high metamorphic grade), or thinly interbedded, gray micritic metalimestone, limy metasandstone, metasiltstone, and slate or pelitic schist (low metamorphic grade); a conglomerate member; euxinic shale lenses; Taylor Pond Member of Hussey (1983), consisting of feldspathic biotite- and hornblende-biotite granofels, thinly bedded calc-silicate rocks, and sparse garnet-rich laminations (coticule); an unnamed limestone member similar to Patch Mountain Limestone Member but at a higher stratigraphic level; and Thorncrag Hill Member of Hussey (1983), consisting of migmatitic pelitic gneiss and some calc-silicate rocks. Anasagunticook Member of Pankiwskyj and others (1976) and Moench and Pankiwskyj (1988) is tentatively reassigned to Waterville Formation, following usage of Osberg (1988). (ME004) Unit description from USGS GEOLEX website (ME078). AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; GS - Greenschist facies; E - Epidote-amphibolite facies; Protolith R - Interbedded pelite and limestone and/or dolostone.
References
NGMDB product
Counties Androscoggin - Franklin - Kennebec - Oxford - Penobscot - Piscataquis - Somerset