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Geologic units containing hornfels

Arizona

Early Proterozoic metasedimentary rocks (Early Proterozoic)

Metasedimentary rocks, mostly derived from sandstone and shale, with minor conglomerate and carbonate rock. Includes quartz-rich, mostly nonvolcanic Pinal Schist in southeastern Arizona and variably volcanic-lithic sedimentary rocks in the Yavapai and Tonto Basin supergroups in central Arizona. (1600-1800 Ma)

Jurassic sedimentary and volcanic rocks (Jurassic)

Sandstone and conglomerate derived from volcanic rocks with associated intermediate-composition lava flows, breccias, and tuffs. In southern Arizona this unit includes rocks of the Artesa sequence, Pitoikam Formation, Mulberry Wash volcanics, Rudolfo Red Beds, Recreation Red Beds, and Gardner Canyon Formation. In western Arizona it includes the Harquar Formation, rocks of Slumgullion, and related(?) unnamed units in the Kofa and Middle Mountains. This unit is characterized by maroon, brown, and purplish-gray volcanic-lithic sandstone and siltstone, with subordinate to abundant conglomerate, quartz-rich sandstone and sparse limestone. (150-170 Ma)

Jurassic to Cambrian metamorphosed sedimentary rocks (Cambrian to Jurassic)

Highly faulted and folded rocks of units Jv, J_, and Pz, deformed and metamorphosed in Jurassic, Cretaceous and Tertiary time. This unit is restricted to west-central Arizona. (160-540 Ma)

Middle Miocene to Oligocene granitic rocks (Oligocene to Middle Miocene)

Granite to diorite representing solidified magma chambers that were the likely source of overlying and nearby volcanic rocks of map unit Tv. The granitic rocks are typically equigranular and fine- to medium-grained. (14-26 Ma)

California

Carboniferous marine rocks, unit 1 (Western Mojave Desert) (Late Proterozoic to Pennsylvanian)

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Carboniferous marine rocks, unit 7 (Bishop) (Mississippian to Early Permian)

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Carboniferous marine rocks, unit 8 (Mono Lake) (Ordovician to Devonian)

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Jurassic marine rocks, unit 6 (Mono Lake) (Ordovician(?) to Triassic(?))

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Paleozoic marine rocks, undivided, unit 2 (Northern Mojave Desert and Southeastern Sierra Nevada) (Cambrian to Jurassic)

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Paleozoic marine rocks, undivided, unit 3 (Eastern Sierra Nevada) (Late Proterozoic(?) to Mesozoic(?))

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Permian marine sedimentary rocks, unit 1 (Death Valley and Mojave Desert) (Pennsylvanian to Triassic)

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Precambrian rocks, undivided, unit 2 (Mojave Desert and Transverse Ranges) (Early Proterozoic to Miocene)

Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous)

Undivided pre-Cenozoic metasedimentary and metavolcanic rocks of great variety. Mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and minor marble.

Schist of various types and ages, unit 11 (Benton Range) (Late Proterozoic(?) to Paleozoic(?))

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Silurian and/or Ordovician marine rocks, unit 2 (Bishop) (Late Cambrian(?) to Early Permian(?))

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

Triassic marine rocks, unit 1 (Death Valley area and Mojave Desert) (Early to Middle Triassic)

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Triassic marine rocks, unit 4 (West Walker River) (Triassic(?))

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Triassic marine rocks, unit 6 (Southern Sierra Nevada) (Late Triassic to Early Jurassic)

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Triassic marine rocks, unit 7 (Mono Lake) (Paleozoic or Mesozoic)

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Georgia

Mafic Hornfels (Precambrian-Paleozoic)

Mafic Hornfels

Idaho

Alaskite, hornfels, and quartzite, undivided; Mixed Tertiary to Cretaceous intrusions and Middle Proterozoic host rocks, undivided; central Idaho (Eocene and Middle Proterozoic, mixed)

Mixed, highly altered and migmatitic rocks; derived from imbrication and dynamic events.

Biotite schist, hornfels, amphibolite, and mylonite; Middle Proterozoic rocks of the Prichard Formation, metamorphosed near the Cretaceous Kaniksu batholith; northern Belt province (Eocene to Middle Proterozoic)

Intermediate Precambrian age metasediments; generally low-to-medium grade; argillite, siltite and minor quartzite of northern Idaho.

North Carolina

Phyllite and Schist (Cambrian/Late Proterozoic)

Phyllite and Schist - locally laminated and pyritic; includes phyllonite, sheared fine-grained metasediment, and metavolcanic rock. In Lilesville granite aureole, includes hornfels.

New Jersey

Lockatong Formation Arkosic Sandstone facies (Upper Triassic)

Lockatong Formation Arkosic Sandstone facies - Cycles in northern Newark basin are thinner and have arkosic sandstone in lower and upper parts. Upper part of formation in northern basin composed mostly of light-gray to light-pinkish-gray or light-brown, coarse- to fine-grained, thick- to massive-bedded arkosic sandstone (Trla). Thermally metamorphosed into hornfels where intruded by diabase (Jd).

Texas

Cienequita Formation (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle Pennsylvanian-Late)

Cienequita Formation

Mundy Breccia and Castner Limestone, undivided (preCambrian-Proterozoic)

Mundy Breccia and Castner Limestone, undivided

Vermont

Albee Formation (Ordovician)

Albee Formation - Massive, gray, white-weathered quartzite and feldspathic quartzite interbedded with greenish-gray slate, phyllite, feldspthic phyllite and quartzose argillaceous phyllite. Micaceous quartzite, quartz-mica schist, mica schist and hornfels contining porphyroblasts of biotite, garnet, staurolite and sillimanite in the vicinity of granitic plutons. Soda-rhyolite tuff occurs locally. Micaceous quartzite characterized by thin, schistose "pinstripe" partings is common in many areas.

Waits River Formation, Barton River Member (Devonian)

Waits River Formation, Barton River Member - Interbedded siliceous crystalline limestone and sercite-quartz-chlorite phyllite in northern Vermont; diopsidic limestone and cordierite hornfels at contacts with granitic dikes and sills.

Washington

Pre-Tertiary metamorphic rocks, undivided (Probably Permian)

Schist, gneiss, marble, quartzite, amphibolite, greenstone, metaconglomerate, graywacke; includes metasedimentary, volcanic, and intrusive rocks. Some areas, as on San Juan Islands, show little if any metamorphism.

Pre-Tertiary sedimentary and metasedimentary rocks, undivided (Mostly Early Cretaceous to Middle Jurassic, possibly includes minor Eocene rocks)

Graywacke, argillite, phyllite, chert, talc, and graphite schist; some faulted-in blocks of serpentinite and greenstone. Includes minor limestone on San Juan Island.

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.