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Mineral Resources > Online Spatial Data > Geology > by state > New York Geology

Geologic units in Jefferson county, New York

Leucogranitic (alaskitic) gneiss (Middle Proterozoic) at surface, covers 2 % of this area

Leucogranitic (alaskitic) gneiss - sodic plagioclase ranges from generally subordinate to locally dominant; locally with biotite, hornblende, pyroxene, garnet, sillimanite, disseminated magnetite; commonly contains metasedimentary layers, amphibolite, migmatite; plagioclase-rich variety is host to magnetite ore bodies in eastern Adirondacks.

Lithology: granitic gneiss; metasedimentary rock; amphibolite; migmatite

Glacial and Alluvial Deposits (Quaternary) at surface, covers 5 % of this area

Glacial and Alluvial Deposits - underlying bedrock geology unknown.

Lithology: alluvium; glacial drift

Charnockite, granitic and quartz syenite gneiss (Middle Proterozoic) at surface, covers 0.1 % of this area

Charnockite, granitic and quartz syenite gneiss - variably leucocratic, containing varying amounts of hornblende, pyroxenes, biotite; may contain interlayered amphibolite, metasedimentary gneiss, migmatite. Overprint signifies inequigranular texture or phacoidal structure.

Lithology: granulite; felsic gneiss; granitic gneiss; amphibolite; migmatite

Hornblende-quartz syenite gneiss (Middle Proterozoic) at surface, covers 0.2 % of this area

Hornblende-quartz syenite gneiss - overprint signifies inequigranular texture.

Lithology: gneiss

Quartzite, quartz-biotite schist and graphitic schist (Middle Proterozoic) at surface, covers 0.4 % of this area

Quartzite, quartz-biotite schist and graphitic schist - in part feldspathic, micaceous, garnetiferous, sillimanitic.

Lithology: quartzite; schist

Amphibolite (Middle Proterozoic) at surface, covers < 0.1 % of this area

Amphibolite - commonly biotitic; garnetiferous, pyroxenic, in and adjacent to Adirondack Highlands.

Lithology: amphibolite

Metanorthosite and anorthositic gneiss (Middle Proterozoic) at surface, covers 0.1 % of this area

Metanorthosite and anorthositic gneiss - mafic mineral percentage contoured in northwestern Marcy massif (St. Regis Quadrangle); contour value shown on high side of countoue line. See also Yach, Yack, Yamu.

Lithology: metavolcanic rock; paragneiss

Black River Group (Middle Ordovician) at surface, covers 21 % of this area

Black River Group - In Black River Valley: Chaumont Limestone-locally cherty; Lowville Limestone; Pamelia Formation-dolostone, shale, arkose. In Champlain Valley: Amsterdam, Isle La Motte, and Lowville Limestones: Pamelia Dolostone.

Lithology: limestone; dolostone (dolomite); shale; arkose; chert

Trenton Group (Middle Ordovician) at surface, covers 28 % of this area

Trenton Group - In Black River Valley: Cobourg Formation-Hillier shale and limestone Member, Hallowell limestone Member; Denley, Sugar River, Kings Falls, and Rockland Limestones. In Champlain Valley: Glens Falls Formation-Montreal shale and limestone Member, Larrabee limestone Member.

Lithology: limestone; shale

Beekmantown Group (in part) (Lower Ordovician) at surface, covers 1 % of this area

Beekmantown Group (in part) - In St. Lawrence Valley: Ogdensburg Dolostone (Beauharnois Dolostone in Canada); In Champlain Valley: Providence Island Dolostone; Fort Cassin Formation-limestone, dolostone; Fort Ann Formation (Spellman of Clinton and Essex Counties)-limestone, dolostone; Cutting Formation-dolostone (locally cherty), limestone, siltstone. In Vermont: includes Bridport, Bascom, Cutting, and Shelburne carbonates.

Lithology: dolostone (dolomite); limestone; chert; siltstone

Biotite and/or hornblende granite gneiss (Middle Proterozoic) at surface, covers 6 % of this area

Biotite and/or hornblende granite gneiss - locally pyroxenic; commonly with subordinate leucogranitic gneiss, biotite-quartz-plagioclase gneiss, other metasedimentary rocks, amphibolite, migmatite. Amphibolite with porphyroblasts of K-feldspar locally prominent in northwest Adirondacks. Overprint signifies inequigranular texture or phacoidal structure. In northwest Adirondacks, grades into Yphg.

Lithology: paragneiss; metasedimentary rock; amphibolite; migmatite

Oswego Sandstone (Upper Ordovician) at surface, covers 1 % of this area

Oswego Sandstone

Lithology: sandstone

Hornblende syenite gneiss (Middle Proterozoic) at surface, covers < 0.1 % of this area

Hornblende syenite gneiss - overprint signifies inequigranular texture.

Lithology: gneiss

Dolomitic and calcitic marbles interlayered with significant amounts of calcsilicate rock (Middle Proterozoic) at surface, covers 0.4 % of this area

Dolomitic and calcitic marbles interlayered with significant amounts of calcsilicate rock - metasedimentary amphibolite, pyroxene granulite, and various gneisses; includes interlayered diopsidic and tremolitic marble and quartzite, and talc-tremolite rock (mined in Balmat-Edwards belt, northwest Adirondacks).

Lithology: marble; calc-silicate rock; amphibolite; granulite; gneiss; quartzite; schist

Potsdam Sandstone (Cambrian) at surface, covers 8 % of this area

Potsdam Sandstone (Covey Hill in Quebec)

Lithology: sandstone

Calcitic and dolomitic marble (Middle Proterozoic) at surface, covers 2 % of this area

Calcitic and dolomitic marble - predominantly; variably siliceous; in part with calcsilicate rock and amphibolite.

Lithology: marble; calc-silicate rock; amphibolite

Theresa Formation (Cambrian - Lower Ordovician) at surface, covers 7 % of this area

Theresa Formation - dolostone, sandstone (Chateauguay in Quebec).

Lithology: dolostone (dolomite); sandstone

Interlayered metasedimentary rock and granitic, charnockitic, mangeritic, or syenitic gneiss (Middle Proterozoic) at surface, covers < 0.1 % of this area

Interlayered metasedimentary rock and granitic, charnockitic, mangeritic, or syenitic gneiss.

Lithology: metasedimentary rock; gneiss

Charnockite, mangerite, pyroxene-quartz syenite gneiss (Middle Proterozoic) at surface, covers < 0.1 % of this area

Charnockite, mangerite, pyroxene-quartz syenite gneiss - overprint signifies inequigranular texture.

Lithology: granulite; monzonite; gneiss

Interlayered amphibolite and granitic, charnockitic, mangeritic, or syenitic gneiss (Middle Proterozoic) at surface, covers 0.1 % of this area

Interlayered amphibolite and granitic, charnockitic, mangeritic, or syenitic gneiss.

Lithology: amphibolite; gneiss

Utica Shale (Middle Ordovician) at surface, covers 4 % of this area

Utica Shale

Lithology: black shale

Mangerite, pyroxene-(hornblende) syenite gneiss (Middle Proterozoic) at surface, covers < 0.1 % of this area

Mangerite, pyroxene syenite gneiss - pyroxene-(hornblende) syenitic gneiss; mesoperthite common. Overprint signifies inequigranular texture.

Lithology: monzonite; paragneiss

Pulaski and Whetstone Gulf Formations (Upper Ordovician) at surface, covers 7 % of this area

Pulaski and Whetstone Gulf Formations - siltstone, shale.

Lithology: siltstone; shale

Biotite-quartz-plagioclase paragneiss, amphibolite, and related migmatite (Middle Proterozoic) at surface, covers 4 % of this area

Biotite-quartz-plagioclase paragneiss, amphibolite, and related migmatite - locally sillimanitic; commonly garnetiferous in and adjacent to Adirondack Highlands.

Lithology: paragneiss; amphibolite; migmatite

Undivided metasedimentary rock and related migmatite (Middle Proterozoic) at surface, covers 1 % of this area

Undivided metasedimentary rock and related migmatite.

Lithology: metasedimentary rock; migmatite