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Geologic units containing mafic metavolcanic rock

Alabama

Poe Bridge Mountain Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock (Precambrian to Paleozoic)

Poe Bridge Mountain Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock. Rocks in the area of Turkey Heaven Mountain in Cleburne and Randolph Counties that are here assigned to the Poe Bridge Mountain Group also have been interpreted as part of the Wedowee Group.

Connecticut

Collinsville Formation (Middle Ordovician)

Collinsville Formation - Mixture of rock types as described for the two members; in many areas felsic and mafic striped metavolcanic rocks predominate.

Taine Mountain and Collinsville Formations undivided (Middle to Lower? Ordovician)

Taine Mountain and Collinsville Formations undivided - see Ot and Oc.

Georgia

Mafic to intermediate metavolcanic rocks (Precambrian-Paleozoic)

Mafic to intermediate metavolcanic rocks

Idaho

Meta-conglomerate mafic metavolcanic rocks, siltite, argillite, and limestone; Late Proterozoic rifted continental margin; northwestern Idaho (Late Proterozoic)

Younger Precambrian mafic volcanic flows and conglomerates of northern Idaho.

Metavolcanic and metasedimentary rocks; Middle to Lower Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex (Middle and Early Triassic)

Middle and Lower Triassic metabasalt and submarine volcaniclastics of western Idaho

Quartzite, siltstone, conglomerate, and metavolcanic rocks; Late and Middle Proterozoic, undivided; Atlanta batholith roof pendants (Late and Middle Proterozoic, undivided)

Precambrian, high-grade metamorphic rock

Maine

Ordovician - Precambrian Z Cape Elizabeth Formation mafic to felsic volcanic member (Ordovician - Precambrian Z)

Ordovician - Precambrian Z Cape Elizabeth Formation mafic to felsic volcanic member

Ordovician - Precambrian Z Cushing Formation (Ordovician - Precambrian Z)

Ordovician - Precambrian Z Cushing Formation

Michigan

Metadiabase (Early Proterozoic)

Metadiabase - Variably metamorphosed dikes, sills and subconcordant sheets of diabasic rocks. Probably coeval (in part) with volcanic rocks of Hemlock Formation (unit Xh)

Minnesota

Mixed metavolcanic rocks (Late Archean)

Mixed metavolcanic rocks - Mafic to felsic volcanic sequences that have variable amounts of felsic volcanogenic and volcaniclastic rocks and lean iron-formation. Includes parts of the Ely Greenstone and the Soudan Iron-formation in northeastern Minnesota.

North Carolina

Amphibolite (Cambrian/Late Proterozoic)

Amphibolite - metamorphosed mafic extrusive and intrusive rock; includes hornblende gneiss, thin layers of mica schist, and small nonlayered masses of metadiorite and metagabbro.

Cid Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic)

(southwest of Asheboro); Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Cid Formation; Mafic Metavolcanic Rock (Cambrian/Late Proterozoic)

(Southwest of Asheboro); Mafic Metavolcanic Rock - metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic)

Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; minor mafic and intermediate metavolcanic rock.

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic)

Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic)

Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic)

Intermediate Metavolcanic Rock - metamorphosed andesitic tuffs and flows, medium to dark grayish green; minor felsic and mafic metavolcanic rock.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic)

Intermediate Metavolcanic Rock - metamorphosed andesitic tuffs and flows, medium to dark grayish green; minor felsic and mafic metavolcanic rock.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic)

Mafic Metavolcanic Rock - metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic)

Mafic Metavolcanic Rock - metamorphosed basaltic to andesitic tuffs and flows, grayish green to black. Locally includes hypabyssal intrusives and minor felsic metavolcanic rock.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic)

Mafic Metavolcanic Rock - metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Metavolcanic Rock (Cambrian/Late Proterozoic)

Metavolcanic Rock - interbedded felsic to mafic tuffs and flowrock.

Metavolcanic Rock (Cambrian/Late Proterozoic)

Metavolcanic Rock - interbedded felsic to mafic tuffs and flowrock.

Uwharrie Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic)

(at Asheboro and to south); Felsic Metavolcanic Rock - metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Yadkin Formation (Cambrian/Late Proterozoic)

Yadkin Formation - metamorphosed graywacke, volcanic sandstone, and siltstone; interbedded with mafic and intermediate metavolcanic flows and tuffs.

New Hampshire

Ammonoosuc Volcanics, Metasedimentary rocks (Middle - Upper Ordovician)

Ammonoosuc Volcanics, Metasedimentary rocks - Contains mafic metavolcanic lenses.

Gile Mountain Formation, Mafic metavolcanic member (Lower Devonian )

Mafic metavolcanic member - Possibly equivalent to Putney Volcanics of southeastern Vermont.

Littleton Formation, Volcanic lentils (Lower Devonian)

Littleton Formation, Volcanic lentils - Both mafic and felsic

Perry Mountain Formation, Sedimentary and subordinate distal felsic and mafic volcanic facies in Piermont allochthon (Lower?- Middle? Silurian)

Perry Mountain Formation, Sedimentary and subordinate distal felsic and mafic volcanic facies in Piermont allochthon.

New Mexico

mafic metamorphic rocks, lower Proterozoic (Proterozoic | Paleoproterozoic)

Lower Proterozoic metamorphic rocks, dominantly mafic (1720-1760 Ma)

New York

Metagabbro (Middle Proterozoic)

Metagabbro - metagabbro, olivine metagabbro, derived amphibolite.

Metagabbro (Middle Proterozoic)

Metagabbro - metagabbro, olivine metagabbro, derived amphibolite.

Pennsylvania

Jonestown Volcanic Suite (Ordovician)

Jonestown Volcanic Suite - Andesite extrusives and dark-greenish-gray metadiabase. Metadiabase weathers medium gray to brown, forming rounded cobbles and boulders.

Metadiabase (Precambrian)

Metadiabase - Dark-gray, fine-grained intrusives; locally, mineralogy is altered and unit has greenish color.

South Carolina

Battleground Formation, Mafic to intermediate metavolcanic rocks (Neoproterozoic)

Battleground Formation, Mafic to intermediate metavolcanic rocks

Mafic to intermediate metavolcanics including layered hornblende gneiss and amphibolite (Ordovician to Neoproterozoic)

Mafic to intermediate metavolcanics including layered hornblende gneiss and amphibolite

Metavolcanic rocks, interlayered felsic to mafic, undivided (Ordovician to Neoproterozoic)

Metavolcanic rocks, interlayered felsic to mafic, undivided

Virginia

Chopawamsic Formation - Mafic to intermediate metavolcanic rocks (Cambrian)

Chopawamsic Formation - Mafic to intermediate metavolcanic rocks

Interlayered Mafic and Felsic Volcanic Rocks (Proterozoic Z)

Interlayered mafic and felsic metavolcanic rocks.

Mafic Igneous Complex Undivided (Proterozoic Z-Cambrian)

Mafic Igneous Complex Undivided - Mafic igneous complex.

Mafic Volcanic Rocks (Proterozoic Z)

Mafic volcanic rocks.

Vermont

Missisquoi Formation, Cram Hill Member (Ordovician)

Missisquoi Formation, Cram Hill Member - Pale greenish-gray to black phyllite grades locally into gray to black slate; felsic to mafic volcanic rocks.

Wisconsin

Mafic to felsic metavolcanic rocks (Early Proterozoic)

Mafic to felsic metavolcanic rocks - Volcanic rocks in areas of sparse geologic data and nondefinitive magnetic and gravity data

Metadiabase (Early Proterozoic)

Metadiabase - Variably metamorphosed dikes, sills and subconcordant sheets of diabasic rocks. Probably coeval (in part) with volcanic rocks of Hemlock Formation (unit Xh).