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Geologic units containing Felsic gneiss

Felsic gneiss
A gneissic rock dominated by light-colored minerals, commonly quartz and feldspar
Subtopics:
Granitic gneiss

Alabama - Colorado - Connecticut - Georgia - Idaho - Massachusetts - Maine - North Carolina - New Hampshire - New Mexico - New York - Pennsylvania - Rhode Island - Virginia

Alabama

Hatchet Creek Group; Pinchoulee Gneiss (Precambrian to Paleozoic)
Pinchoulee Gneiss - medium to fine-grained migmatitic, locally garnetiferous biotite-feldspar gneiss, commonly saturated with granitic pods.
Higgins Ferry Group (Precambrian to Paleozoic)
Higgins Ferry Group - thinly layered coarse to fine-grained biotite-feldspar-quartz gneiss, sericite-feldspar-muscovite schist, +/- biotite +/- garnet-muscovite schist, and biotite-garnet feldspathic gneiss; locally common pegmatites.
Mad Indian Group (Precambrian to Paleozoic)
Mad Indian Group - fine-grained feldspathic biotite gneiss; medium to coarse-grained muscovite-biotite-garnet schist; locally kyanite and sillimanite. Many of the schists have been retrograded to chlorite-garnet-quartz-sericite schist. Both mi and migr extensively cut by feldspathic dikes and pegmatites.
Motts Gneiss (Precambrian to Paleozoic)
Motts Gneiss - leucocratic quartz-rich quartz diorite pencil gneiss.
Opelika Complex; Auburn Gneiss (Precambrian to Paleozoic)
Auburn Gneiss - fine-grained biotite-oligoclase gneiss intermixed with coarse-grained muscovite-biotite schist; locally contains muscovite-rich pegmatite.
Uchee Complex; Phenix City Gneiss (Precambrian to Paleozoic)
Phenix City Gneiss - biotite-epidote quartz diorite gneiss and biotite-hornblende gneiss; locally includes migmatitic amphibolite; cut by numerous granitic veins.
Wedowee Group; Wedowee Group undifferentiated (Precambrian to Paleozoic)
Wedowee Group undifferentiated - Wedowee Group undifferentiated includes the Cragford Phyllite and Cutnose Gneiss. Cragford Phyllite -- interbedded fine-grained graphite-chlorite-sericite schist and phyllite, garnet-sericite schist and phyllite, graphite-quartz-sericite phyllite, locally feldspathic biotite gneiss, calc-silicate rock, and quartzite. Cutnose Gneiss -- cyclically interbedded fine-grained quartz-biotite feldspathic gneiss, graphite-chlorite-sericite schist, locally thin interbeds of graphite-quartz-sericite phyllite, and quartzite. Rocks in the area northeast of Clanton in Chilton and Coosa Counties that are here assigned to the Wedowee Group also have been interpreted as part of the Higgins Ferry Group.

Colorado

Connecticut

Georgia

Idaho

Massachusetts

Ammonoosuc Volcanics (Middle Ordovician)
Ammonoosuc Volcanics - Amphibolite, felsic gneiss, garnet-amphibole quartzite, and marble too thin to show separately at map scale. Gedrite, anthophyllite, cummingtonite locally abundant in amphibolite layers.
Cobble Mountain Formation (Middle Ordovician)
Cobble Mountain Formation - Light-brown, fine- to medium-grained pelitic schist and granofels locally graded in beds less than 15 cm thick. Local amphibolite. Rare calc-silicate rock, feldspar gneiss, coticule and cummingtonite schist.
Collinsville Formation (Middle Ordovician or older)
Collinsville Formation - Interlayered amphibolite and felsic gneiss in beds less than 1 m thick. Local, coarse-grained magnetite-hornblende gneiss.
Collinsville Formation (Middle Ordovician or older)
Collinsville Formation - Amphibolite, locally very garnetiferous, containing beds of felsic gneiss.
Collinsville Formation (Middle Ordovician or older)
Collinsville Formation - Felsic gneiss containing scattered biotite, magnetite, garnet and hornblende. Local beds of amphibolite.
Collinsville Formation (Middle Ordovician or older)
Collinsville Formation - Interlayered amphibolite and white felsic gneiss containing biotite, hornblende, and magnetite. Local calc-silicate beds. Coticule-bearing granofels, muscovite quartzite and amphibolite in upper part.
Intimately interfolded Littleton and Partridge Formations (Lower Devonian and Middle Ordovician)
Intimately interfolded Littleton and Partridge Formations - In areas of poor exposure and incomplete mapping.
Littleton Formation (Lower Devonian)
Littleton Formation - Quartz-feldspar-garnet gneiss, probably originally felsic volcanic rocks.
Partridge Formation (Middle Ordovician)
Partridge Formation (includes Brimfield Schist of Emerson, 1917) - Felsic gneiss of volcanic derivation and minor amphibolite.
Partridge Formation (Middle Ordovician)
Partridge Formation (includes Brimfield Schist of Emerson, 1917) - Layered felsic gneiss and schist.
Partridge Formation (Middle Ordovician)
Partridge Formation (includes Brimfield Schist of Emerson, 1917) - Mafic and felsic gneisses of volcanic derivation with calc-silicate granofels.
Pinkish-gray, fine-grained, well-laminated felsic biotite-microcline-plagioclase-quartz gneiss (Proterozoic Y)
Pinkish-gray, fine-grained, well-laminated felsic biotite-microcline-plagioclase-quartz gneiss - Probably metamorphosed rhyolite.
Quinebaug Formation (Ordovician, Cambrian, or Proterozoic Z)
Quinebaug Gneiss - Amphibolite, biotite and hornblende gneiss, felsic gneiss, and calc-silicate gneiss.

Maine

North Carolina

New Hampshire

New Mexico

New York

Pennsylvania

Rhode Island

Virginia