Manhattan Formation (A Member) (NYOma;3)

State	New York
Name	Manhattan Formation (A Member)
Geologic age	Middle Ordovician
Lithologic constituents	Major Metamorphic > Metasedimentary > Metacarbonate > Marblecalcite marble Metamorphic > Metasedimentary > Calc-silicate-rock Metamorphic > Schist > Mica-schistsillimanite-garnet-muscovite-biotite-quartz-plagioclase schists
Comments	part of Trenton Group and Metamorphic Equivalents up to 8000 ft. (2400 m). This unit (Oma) is described under unit ?Om on printed map. Separated out, because it is used separately in digital map. Named it 'A Member' of Manhattan Formation. Second unit description from USGS Lexicon website (ref. NY046) and reference NY004: Manhattan Schist member A replaced by Walloomsac Formation (not new) based on work by Jackson and Hall (1982), Hall (in press), and A.A. Drake (1990, pers. commun.). In addition, L.M. Hall (1985?, pers. commun.) determined that member B of the Manhattan Schist is part of member C and thus recommended the abandonment of member B (Baskerville, 1992).
References	Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250,000. Baskerville, C.A., 1992, Bedrock and engineering geologic maps of Bronx County and parts of New York and Queens Counties, New York: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2003, 2 sheets, scale 1:24,000. https://pubs.er.usgs.gov/publication/i2003 USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/ https://ngmdb.usgs.gov/Geolex/search
NGMDB product	NGMDB product page for 98670
Counties	Putnam - Rockland - Westchester

State

New York

Name

Manhattan Formation (A Member)

Geologic age

Middle Ordovician

Lithologic constituents

Major

Metamorphic > Metasedimentary > Metacarbonate > Marblecalcite marble

Metamorphic > Metasedimentary > Calc-silicate-rock

Metamorphic > Schist > Mica-schistsillimanite-garnet-muscovite-biotite-quartz-plagioclase schists

Comments

part of Trenton Group and Metamorphic Equivalents up to 8000 ft. (2400 m). This unit (Oma) is described under unit ?Om on printed map. Separated out, because it is used separately in digital map. Named it 'A Member' of Manhattan Formation. Second unit description from USGS Lexicon website (ref. NY046) and reference NY004: Manhattan Schist member A replaced by Walloomsac Formation (not new) based on work by Jackson and Hall (1982), Hall (in press), and A.A. Drake (1990, pers. commun.). In addition, L.M. Hall (1985?, pers. commun.) determined that member B of the Manhattan Schist is part of member C and thus recommended the abandonment of member B (Baskerville, 1992).

References

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250,000.

Baskerville, C.A., 1992, Bedrock and engineering geologic maps of Bronx County and parts of New York and Queens Counties, New York: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2003, 2 sheets, scale 1:24,000.

https://pubs.er.usgs.gov/publication/i2003

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/

https://ngmdb.usgs.gov/Geolex/search

NGMDB product

NGMDB product page for 98670

Counties

Putnam - Rockland - Westchester