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Geologic units containing pyroxenite

Alabama

Dadeville Complex; Mafic and ultramafic rock (Precambrian to Paleozoic)

Mafic and ultramafic rock - ultramafic rock including enstatite pyroxenite, layered actinolite-tremolite amphibolite altered locally to serpentine, anthophyllite, and talc; metanorite; metagabbro; hornblendite; garnet-hornblendite, and massive amphibolite.

Ultramafic rock (Precambrian to Paleozoic)

Ultramafic rock - ultramafic pods and sheets, principally enstatite-hypersthene pyroxenite with hornblende and actinolite alteration assemblages.

Arizona

Early Proterozoic granitic rocks (Early Proterozoic)

Wide variety of granitic rocks, including granite, granodiorite, tonalite, quartz diorite, diorite, and gabbro. These rocks commonly are characterized by steep, northeast-striking foliation. (1600-1800 Ma)

California

Mesozoic granitic rocks, unit 5 (Klamath Mountains) (Jurassic to early Cretaceous)

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Ultramafic rocks, chiefly Mesozoic, unit 1 (Trinity Ophiolite) (Ordovician)

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 1

Ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) (Late Proterozoic(?) to Early Jurassic)

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 2

Connecticut

Litchfield Norite (Middle? Ordovician)

Litchfield Norite - Dark, medium- to coarse-grained, mostly massive mafic rock (olivine norite, quartz norite, hypersthene pyroxenite), composed of labradorite, hypersthene, augite, and olivine in varying proportions, also hornblende and biotite (and minor quartz in quartz norite). Associated with small mineral deposits of pyrrhotite, pentlandite, and chalcopyrite.

Idaho

Syenite, quartz syenite, monzodiorite, quartz diorite, gabbro, pyroxenite, and hornblendite; Late Proterozoic plutons; east-central Idaho (Late Proterozoic)

Younger or Intermediate Precambrian age intrusive rock undifferentiated.

Massachusetts

Diorite at Goff Ledges (Ordovician)

Diorite at Goff Ledges - Diorite at Goff Ledges (Ogd) and similar diorite (Od) in the Windsor quadrangle. Very coarse-grained to pegmatitic, slightly foliated hornblende-plagioclase diorite, minor hornblende pyroxenite. Ogd intrudes CAZh and CAZhk. Od intrudes the Rowe Schist of the Rowe-Hawley zone.

Diorite at Goff Ledges (Ordovician)

Diorite at Goff Ledges - Diorite at Goff Ledges (Ogd) and similar diorite (Od) in the Windsor quadrangle. Very coarse-grained to pegmatitic, slightly foliated hornblende-plagioclase diorite, minor hornblende pyroxenite. Ogd intrudes CAZh and CAZhk. Od intrudes the Rowe Schist of the Rowe-Hawley zone.

Maryland

Baltimore Gabbro Complex (Late Precambrian (?) - Early Paleozoic )

Baltimore Gabbro Complex - Hypersthene gabbro with subordinate amounts of olivine gabbro, norite, anorthositic gabbro, and pyroxenite; igneous minerals and textures well preserved in some rocks, other rocks exhibit varying degrees of alteration and recrystallization with a new metamorphic mineral assemblage.

Ultramafic and Gabbroic Rocks (Early Paleozoic (?))

Ultramafic and Gabbroic Rocks - Mixed metagabbro, serpentinite, metapyroxenite, and actinolite-, chlorite-, and epidote-bearing schists.

Ultramafic Rocks (Early Paleozoic - Late Precambrian (?))

Ultramafic Rocks - Chiefly serpentinite with partly to completely altered dunite, peridotite, pyroxenite, and massive to schistose soapstone; talc-carbonate rock and altered gabbro are common in some bodies.

Maine

Cambrian Hurricane Mountain Formation, metapyroxenite (Cambrian)

Cambrian Hurricane Mountain Formation, metapyroxenite

Minnesota

Post-tectonic intrusions of the Penokean orogen (Early Proterozoic)

Post-tectonic intrusions of the Penokean orogen - Small stocks of olivine pyroxenite in Morrison County; small plutons of hornblende-rich diorite and gabbro that contain layers and lenses of nelsonite, pyroxenite, and anorthosite in Todd County.

Post-tectonic mafic intrusions (Late Archean)

Post-tectonic mafic intrusions - Gabbro, peridotite, pyroxenite, and their metamorphic equivalents. Unit also includes small intrusive complexes of anorthosite, gabbroic anorthosite, and anorthositic gabbro. Generally characterized by pronounced magnetic signatures.

Nevada

Metamorphic rocks (Early Proterozoic)

METAMORPHIC ROCKS-Gneiss and schist and lesser amounts of gneissic granite, pyroxenite, hornblendite, migmatite, pegmatite, and marble.

New York

Gabbro or norite to hornblende diorite (Upper Ordovician)

Gabbro or norite to hornblende diorite - rock complex with minor pyroxenite; Croton Falls and Peach Lake complexes in New York, and Mt. Prospect Complex in Connecticut.

Olivine pyroxenite (Upper Ordovician)

Olivine pyroxenite - in part with poikilitic hornblende; local peridotite.

Pyroxenite (Upper Ordovician)

Pyroxenite

Oregon

Gabbro and ultramafic rocks associated with granitic plutons (Cretaceous and Jurassic) (Late Jurassic and Early Cretaceous)

Predominantly hornblende gabbro, gabbro, and olivine gabbro, but includes pyroxenite, hornblende pyroxene, and minor peridotite, dunite, and serpentinite (Smith and others, 1982)

Ultramafic and mafic intrusive rocks and serpentinized equivalents (Triassic and Paleozoic) (Paleozoic to Triassic)

Peridotite, pyroxenite, gabbro, and norite. Light-green, gray, and black serpentine, mostly derived from peridotite; commonly highly sheared; in places includes some metavolcanic rocks and metamorphosed inclusions of keratophyre and chert. Includes ultramafic and mafic phases of the ophiolitic Canyon Mountain Complex of Thayer (1963; 1977) and Brown and Thayer (1966), alpine mafic rocks of Wolff (1965), gabbro of Ashley (1967), and serpentinite-matrix melange of Brooks and others (1983) and Ferns and others (1983):

Pennsylvania

Ultramafic rocks (Probably lower Paleozoic)

Ultramafic rocks - Includes serpentine, steatite, and other products of alteration of peridotites and pyroxenites.

South Carolina

Hammett Grove Meta-igneous Suite - ultramafic rocks (Paleozoic or Neoproterozoic)

Hammett Grove Meta-igneous Suite - ultramafic rocks: metamorphosed ultramafic rocks: hornblendite, pyroxenite, serpentinite and talc schist

Virginia

Lahore Complex - Mafic and ultramafic rocks (Ordovician)

Lahore Complex - Mafic and ultramafic rocks

Washington

Pre-Carboniferous crystalline complex (Devonian)

Metahornblendite, amphibolite, gneiss, metadiorite, meta-quartz diorite, and trondhjemite. As klippes along western slope of northern Cascade Mountains.

Pre-Carboniferous intrusive rocks (Paleozoic)

Meta-quartz diorite, hypersthene diorite, and gneissose and directionless quartz diorite of eastern Skagit County. Quartz diorite and diorite in the San Juan Islands. Includes amphibolite and gneiss locally.

Pre-Tertiary basic intrusive rocks (Triassic-Permian)

Predominantly gabbro and metagabbro; includes hornblendite, peridotite, and pyroxenite. In Nighthawk district and near 49th Parallel in Okanogan County and in Orient district of Stevens County.

Pre-Tertiary ultrabasic intrusive rocks (Late-Jurassic)

Peridotite and pyroxenite; generally altered partly or completely to serpentine. Includes serpentinite and saxonite on Sumas Mountain, Whatcom County.