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Geologic units containing amphibole schist

Georgia

Amphibolitic Schist (Precambrian-Paleozoic)

Amphibolitic Schist

Amphibolitic Schist/ Amphibolite (Precambrian-Paleozoic)

Amphibolitic Schist/ Amphibolite

Amphibolitic Schist/ Amphibolite-Metagraywacke/ Mica Schist (Precambrian-Paleozoic)

Amphibolitic Schist/ Amphibolite-Metagraywacke/ Mica Schist

Quartz Mica Schist/ Hornblende Schist/ Biotitic Gneiss (Precambrian-Paleozoic)

Quartz Mica Schist/ Hornblende Schist/ Biotitic Gneiss

Massachusetts

Gile Mountain Formation (Lower Devonian)

Gile Mountain Formation - Amphibolite, hornblende schist.

Gneiss and schist near New Bedford (Proterozoic Z)

Gneiss and schist near New Bedford - Hornblende and biotite schist and gneiss, amphibolite.

Waits River Formation (Lower Devonian)

Waits River Formation - Amphibolite or hornblende schist locally containing conspicuous hornblende or garnet megacrysts. Rocks mapped as Conway Schist by Emerson (1898, 1917) and subsequently subdivided by Segerstrom (1956) and Willard (1956) were mapped across the MA-VT State line as Waits River and Gile Mountain Formations by Doll and others (1961) on Centennial Geologic Map of Vermont. Although controversy still exists over relative ages, detailed reconnaissance mapping by authors and S.F. Clark, Jr., L.M. Hall, and J.W. Pferd shows that Waits River and Gile Mountain Formations are readily distinguished in the field. For these reasons, and to maintain continuity across the State line, authors chose to follow VT nomenclature on here and on MA State bedrock geologic map (Zen and others, 1983). Primary difference between Waits River and Gile Mountain is presence in Gile Mountain of beds of noncalcareous, commonly micaceous quartzite. Both formations contain conspicuous beds of punky brown-weathering impure marble or calcareous granulite, mostly in Waits River and less abundant in Gile Mountain. Predominant lithology of both formations is typically contorted gray, graphitic, locally very sulfidic, moderately aluminous mica schist containing quartz veins. Gradational but definitely significant boundary can be mapped between both formations. Amphibolite in both formations may correlate with Standing Pond Volcanics occurring at or near Waits River-Gile Mountain contact in VT. Report goes into great detail regarding informal subdivision of each formation. Rocks previously mapped as Waits River Formation northeast of Shelburne Falls dome by Hatch and Hartshorn (1968) are here reassigned to an unnamed member of Goshen Formation because the rocks are indistinguishable from the Goshen. Goshen-Waits River contact is defined as the line along which, going eastward, the schist changes from aluminous, planar-bedded, and virtually quartz-free (Goshen), to alumina-poor, contorted, and rich in quartz veins (Waits River) (Hatch and others, 1988).

Tennessee

Cranberry Granite (Precambrian)

Cranberry Granite - Complex of intertonguing rock types including migmatite, granitic gneisses, monzonite, quartz diorite, greenstone, mica and hornblende schists, abundant granitic pegmatite.

Texas

Packsaddle Schist (preCambrian-Proterozoic [Llano])

Packsaddle Schist

Valley Spring Gneiss (preCambrian-Proterozoic)

Valley Spring Gneiss

Vermont

Pinney Hollow Formation, Chester Amphibolite Member (Cambrian)

Pinney Hollow Formation, Chester Amphibolite Member - Thin-layered, ligniform amphibolite and hornblende schist; includes actinolitic greenstone and greenstone north of Windham. (Southern and Central Vermont).

Washington

Pre-Upper Jurassic metamorphic rocks of the low-grade zone (Jurassic)

Greenschist, phyllite, and slate; includes some limestone, quartzose phyllite, schistose metaconglomerate, breccia, and basic igneous rocks. Includes schist locally.