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Geologic units containing paragneiss

Idaho

Garnet-mica schist, gneiss, and quartzite; Proterozoic high-grade metasedimentary rocks; trans-Idaho metamorphic province (Late to Early Proterozoic)

Precambrian high-grade metamorphic rock; metasediment; Kyanite-sillimanite-garnet-mica schist and gneiss; minor quartzite

High-grade metasedimentary biotite schist, biotite gneiss, and calc-silicate gneiss; Middle Proterozoic northern Belt province near Idaho batholith (Middle Proterozoic)

Precambrian high-grade metamorphic rock; kyanite-sillimanite calc-silcate bearing schist and gneiss; scapolite common

Mica schist, quartzite, gneiss, and amphibolite; Late to Early Proterozoic high-grade metasedimentary rocks (subunits are ZXmhs, ZXmhq, and ZXmhc); trans-Idaho metamorphic province (Proterozoic)

Precambrian high-grade metamorphic rock; metasediment

Migmatitic paragneiss, quartzite, orthogneiss, and amphibolite; Early Proterozoic to Late Archean metamorphic rocks; northern Belt province; Settlement antiform in Priest River metamorphic core complex (Early Proterozoic to Late Archean)

Precambrian, high-grade metamorphic rock; metasediment; kyanite-sillimanite garnet-mica coarse-grained schist and gneiss; minor quartzite

Massachusetts

Massabesic Gneiss Complex (Ordovician and Proterozoic Z)

Massabesic Gneiss Complex - Biotite-feldspar paragneiss of Proterozoic Z age intruded by potassium-feldspar-rich gneiss of Ordovician age.

Maryland

Baltimore Gneiss (Precambrian)

Baltimore Gneiss - Biotite-quartz-feldspar gneiss and biotite-hornblende gneiss; amphibolite widespread but subordinate; texturally varied; granitic gneiss, veined gneiss, augen gneiss, banded gneiss, and migmatite, in places complexly intermingled; age 1,1000 m.y. * by radiogenic dating. Layered paragneiss in Baltimore City southeast of Relay Quartz Diorite.

James Run Gneiss (Late Precambrian (?))

James Run Gneiss - Thick-bedded, light gray biotite-quartz-plagioclase gneiss with thin interbeds of quartz amphibolite; grades downward into sharply layered, thin- to thick-bedded paragneiss composed of subequal amounts of biotite-quartz-plagioclase gneiss and quartz amphibolite; thickness unknown.

Minnesota

Paragneiss and schist-rich migmatite (Late Archean)

Paragneiss and schist-rich migmatite - Grades into undivided metasedimentary rocks (unit Ams).

Paragneiss, schist, and amphibolite (Late Archean)

Paragneiss, schist, and amphibolite - Amphibolite-facies equivalent of units Amv and Ams; locally includes abundant intrusions of unit Agr.

North Carolina

Biotite Granitic Gneiss (Middle Proterozoic)

Biotite Granitic Gneiss (950-1250 my) - unconformity; contains paragneiss and granitic to quartz monzonitic orthogneiss; locally schistose and mylonitic. Locally includes tectonic slices, infolded remnants, or recrystallized equivalents of the Grandfather Mountain Formation. Equivalent to the Wilson Creek Gneiss.

New Jersey

Biotite-Quartz-Feldspar Gneiss (Middle Proterozoic)

Biotite-Quartz-Feldspar Gneiss - Gray-weathering, locally rusty, gray to tan or greenish-gray, fine- to medium-coarse-grained, moderately layered and foliated gneiss that is variable in texture and composition. Composed of oligoclase, microcline microperthite, quartz, and biotite. Locally contains garnet, graphite, sillimanite, and opaque minerals.

Clinopyroxene-Quartz-Feldspar Gneiss (Middle Proterozoic)

Clinopyroxene-Quartz-Feldspar Gneiss - Pinkish-gray- or pinkish-buff-weathering, white to pale-pinkish-white or light-gray, fine- to medium-grained, massive to moderately well-layered gneiss composed of microcline, quartz, oligoclase, clinopyroxene, and trace amounts of epidote, biotite, titanite, and opaque minerals. Commonly interlayered with amphibolite or pyroxene amphibolite.

Epidote Gneiss (Middle Proterozoic)

Epidote Gneiss - Light-gray- to pinkish-white-weathering, light-grayish-pink to pinkish-white, medium-grained, moderately layered and foliated gneiss containing quartz, microcline, and epidote. Some phases contain scapolite. May be interlayered with and related to potassium-feldspar gneiss (Yk), and (or) clinopyroxene-quartz-feldspar gneiss (Ymp). Two elongate bodies mapped east of Franklin.

Hornblende Granite (Middle Proterozoic)

Hornblende Granite - Pinkish-gray- to medium-buff-weathering, pinkish-white or light-pinkish-gray, medium- to coarse-grained, gneissoid to indistinctly foliated granite and sparse granite gneiss composed principally of microcline microperthite, quartz, oligoclase, and hornblende. Some phases are quartz syenite or quartz monzonite. Includes small bodies of pegmatite and amphibolite not shown on map. U-Pb age approximately 1,090 Ma (Drake and others, 1991b).

Hornblende-Quartz-Feldspar Gneiss (Middle Proterozoic)

Hornblende-Quartz-Feldspar Gneiss - Pinkish-gray- to buff-weathering, light- pinkish-white to pinkish-gray, fine- to medium-grained, massive to moderately well layered gneiss containing microcline, quartz, oligoclase, hornblende, and magnetite. Locally contains garnet and biotite.

Microcline Gneiss (Middle Proterozoic)

Microcline Gneiss - Light-gray- to pinkish-white-weathering, tan to pinkish-white, fine- to medium-grained, well-layered gneiss composed principally of quartz, microcline, and lesser amounts of oligoclase. Common accessory minerals include biotite, garnet, magnetite, and, locally, sillimanite.

Potassic Feldspar Gneiss (Middle Proterozoic)

Potassic Feldspar Gneiss - Light-gray- to pinkish-buff-weathering, pinkish-white to light-pinkish-gray, fine- to medium-grained, moderately foliated gneiss and lesser amounts of granofels composed of quartz, microcline, microcline microperthite and local accessory amounts of biotite, garnet, sillimanite, and opaque minerals.

Pyroxene-Epidote Gneiss (Middle Proterozoic)

Pyroxene-Epidote Gneiss - White- to light-gray-weathering, light-greenish-gray or greenish-buff, fine- to medium-grained, moderately layered and foliated gneiss composed principally of quartz, microcline, plagioclase, clinopyroxene, epidote, and sparse amounts of titanite. Some phases of this unit are quartz-rich. May be interlayered and probably related to pyroxene gneiss (Yp).

Pyroxene Gneiss (Middle Proterozoic)

Pyroxene Gneiss - White- to tan-weathering, greenish-gray, fine- to medium-grained, well-layered gneiss containing oligoclase, clinopyroxene, variable amounts of quartz, and trace amounts of opaque minerals and titanite. Some phases contain scapolite and calcite. Commonly interlayered with pyroxene amphibolite or marble.

New York

Biotite and/or hornblende granite gneiss (Middle Proterozoic)

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.

Biotite-quartz-plagioclase paragneiss (Middle Proterozoic)

Biotite-quartz-plagioclase paragneiss - commonly very low in biotite content, with interbedded feldspathic and biotitic quartzite and amphibolite; sillimanite and garnet common, graphite sporadic.

Biotite-quartz-plagioclase paragneiss, amphibolite, and related migmatite (Middle Proterozoic)

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

Garnet-bearing gneiss and interlayered quartzite (Middle Proterozoic)

Garnet-bearing gneiss and interlayered quartzite - contains varying amounts of biotite, garnet, sillimanite; minor marble, amphibolite, rusty paragneiss.

Mangerite, pyroxene-(hornblende) syenite gneiss (Middle Proterozoic)

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

Metanorthosite and anorthositic gneiss (Middle Proterozoic)

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.

Metanorthosite and anorthositic gneiss (Middle Proterozoic)

Metanorthosite and anorthositic gneiss.

Pennsylvania

Banded mafic gneiss (Precambrian)

Banded mafic gneiss - Dark, fine to medium grained; includes rocks of probable sedimentary origin; may be equivalent to "PZmgh."

Felsic and intermediate gneiss (Precambrian)

Felsic and intermediate gneiss - Light, medium grained; includes rocks of probable sedimentary origin.

Felsic gneiss (Precambrian)

Felsic gneiss - Light, medium grained; includes rocks of probable sedimentary origin.

Graphitic felsic gneiss (Precambrian)

Graphitic felsic gneiss - Includes Pickering Gneiss and small areas of marble; dominantly quartz and feldspar with varying amounts of graphite and various metamorphic minerals; medium grained, light to dark gray and greenish gray; sedimentary origin.

Hornblende gneiss (Precambrian)

Hornblende gneiss - Dark, medium grained; includes some rocks of probable sedimentary origin.

Mafic gneiss (Precambrian)

Mafic gneiss - Dark, medium grained; includes rocks of probable sedimentary origin; may be equivalent to "PZmgp" in places.

Mafic gneiss (Precambrian)

Mafic gneiss - Dark, medium grained; includes rocks of probable sedimentary origin; may be equivalent to "PZmgh" in places.

Mafic gneiss (Probably lower Paleozoic)

Mafic gneiss - Dark, medium grained; includes rocks of probable sedimentary origin; may be equivalent to pCAmgh in places.

Mafic gneiss (Probably lower Paleozoic)

Mafic gneiss - Dark, medium grained; includes rocks of probable sedimentary origin; may be equivalent to pCAmgp in places.

South Carolina

Migmatite paragneiss and schist of Kiokee belt (Cambrian or Neoproterozoic)

Migmatite paragneiss and schist of Kiokee belt: migmatitic hornblende-biotite paragneiss having interlayered sillimanite schist and amphibolite

Tallulah Falls Formation, gneiss and schist (Neoproterozoic)

Tallulah Falls Formation, gneiss and schist: biotite-quartz-plagioclase gneiss interpreted to be metagraywacke, and interlayered biotite-muscovite schist, garnet-mica schist and amphibolite

Texas

Lost Creek Gneiss (preCambrian-Proterozoic)

Lost Creek Gneiss

Valley Spring Gneiss (preCambrian-Proterozoic)

Valley Spring Gneiss

Virginia

Garnet-Graphite Paragneiss (Proterozoic Y)

Garnet-graphite paragneiss

Migmatitic Paragneiss (Proterozoic)

Migmatitic paragneiss.

Washington

Lower Paleozoic rocks, undivided (Paleozoic; likely Ordovician)

Predominantly gneiss and schist in northern Ferry County. Quartzite, partly interbedded with dolomitic and calcitic marble, lime-silicate gneiss, and amphibolite; including in places forsterite marblean diopside marble, quartz-biotite-sillimanite schist and sillimanite-orthoclase gneiss in northeastern Ferry County. Quartzite with overlying limestone in southeastern Stevens County. Some upper Paleozoic and Precambrian rocks may be included.