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Geologic units containing trachyte

Arkansas

Igneous rocks (Phanerozoic | Mesozoic | Cretaceous)

Includes undifferentiated altered sedimentary rocks of Paleozoic age at Granite Mountain, Pulaski County, and Mufreesboro, Pike County. Acid to intermediate - Nepheline syenite complexes at Magnet Cove and Potash Sulfur Springs, stocks at Granite Mtn., explosion breccias, and dikes and sills (principally trachyte,tinguaite, phonolite, some ranging from syenite to diabase.) Basic to ultrabasic - Lamproite pipes (Murfreesboro, Pike County) and dikes and sills (principally lamprophyres of fourchite, ouachitite, and monchiquite)

Arizona

Holocene to middle Pliocene basaltic rocks (Middle Pliocene to Holocene)

Mostly dark-colored basaltic lava and cinders young enough that some original volcanic landforms are still apparent. Includes a small amount of andesite, dacite, and rhyolite. Rocks of this map unit are largely restricted to six areas widely distributed in Arizona: San Francisco and Uinkaret volcanic fields in northern Arizona (0-4 Ma); Springerville (0-4 Ma) and San Carlos (0-2 Ma) volcanic fields in east-central Arizona; and San Bernardino (0-1 Ma) and Sentinel (1-4 Ma) volcanic fields in southern Arizona. Rocks of this unit are also present in the extreme southwestern part of Arizona where they were erupted at the edge of the Pinacate volcanic field (0-2 Ma) in northwestern Sonora. (0-4 Ma)

Middle Miocene to Oligocene volcanic rocks (Oligocene to Middle Miocene)

Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)

California

Tertiary intrusive rocks (hypabyssal), unit 7 (Northern Mojave Desert) (Tertiary)

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Tertiary volcanic flow rocks, unit 16 (Northern Mojave Desert) (Tertiary (4-22 Ma))

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary volcanic flow rocks, unit 18 (San Joaquin-Kings Canyon) (Tertiary (3-4 Ma))

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Idaho

Rhyolite ot trachyte ignimbrites and flows; Pliocene felsic volcanics; eastern Snake River Plain and vicinity (Pliocene)

Pliocene silicic welded tuff, ash, and flow rock; most common in southwestern Idaho.

Trachyandesite, latite, trachybasalt flows, dikes, and volcaniclastic debris; Eocene intermediate volcanics; central Idaho, southern Challis volcanic field (Eocene)

Eocene mixed silicic and basaltic volcanic ejecta, flows and reworked debris.

Missouri

ST. FRANCOIS MOUNTAINS VOLCANIC SUPERGROUP (Precambrian [Y])

ST. FRANCOIS MOUNTAINS VOLCANIC SUPERGROUP (chiefly alkali rhyolitic ash - flow tuffs, lava flows, and bedded tuffs, with minor trachytes.

New Hampshire

Moat Volcanics (Middle Jurassic?)

Moat Volcanics - Bedded and ignimbritic tuffs, flows, and breccias; also porphyritic rhyolite and minor trachyte.

New Jersey

Lamprophyre, tinguaite (phonolite with acicular acmite crystals), phonolite, bostonite (trachyte), and malignite (mafic nepheline syenite), undifferentiated (Silurian - Ordovician)

Lamprophyre, tinguaite (phonolite with acicular acmite crystals), phonolite, bostonite (trachyte), and malignite (mafic nepheline syenite), undifferentiated - Light-medium- to medium-dark-gray, aphanitic to fine-grained, alkalic to calcic-alkalic dikes and sills. Unit intrudes rocks from the Middle Proterozoic to the High Point Member of the Martinsburg Formation, but does not intrude the Shawangunk Formation. K-Ar data of 422 +/- 14 Ma from biotite phenocrysts in a minette (lamprophyre with biotite phenocrysts) dike (Charles Milton, written communication, 1972) suggests an Early Silurian age for some of these rocks.

New Mexico

felsic shallow-intrusive rocks (Phanerozoic | Cenozoic | Tertiary)

Middle Tertiary felsic shallow-intrusive rocks; phonolites and trachytes of northeastern N.M.; includes the rhyolite of Ash Mountain

Nevada

Andesite and related rocks of intermediate composition (Early Oligocene to Early Miocene)

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Andesite and related rocks of intermediate composition (Late Miocene to Middle Miocene)

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Ash-flow tuffs and tuffaceous sedimentary rocks (Middle Miocene to Late Miocene)

ASH-FLOW TUFFS AND TUFFACEOUS SEDIMENTARY ROCKS

Ash-flow tuffs, rhyolitic flows, and shallow intrusive rocks (Middle Miocene to Late Miocene)

ASH-FLOW TUFFS, RHYOLITIC FLOWS, AND SHALLOW INTRUSIVE ROCKS

Rhyolitic flows and shallow intrusive rocks (Late Eocene to Middle Eocene)

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Rhyolitic flows and shallow intrusive rocks (Middle Miocene to Late Miocene)

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Rhyolitic flows and shallow intrusive rocks (Miocene to Quaternary)

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Rhyolitic flows and shallow intrusive rocks (Early Oligocene to Early Miocene)

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Shale, sandstone, volcanogenic clastic rocks, andesite, rhyolite, and locally thick carbonate units (Late Triassic to Early Cretaceous)

SHALE, SANDSTONE, VOLCANOGENIC CLASTIC ROCKS, ANDESITE, RHYOLITE, AND LOCALLY THICK CARBONATE UNITS-Undivided sequence locally containing recognizable equivalents of the Luning and Dunlap Formations

Welded and nonwelded silicic ash-flow tuffs (Early Oligocene to Early Miocene)

WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS-Locally includes thin units of air-fall tuff and sedimentary rock

Welded and nonwelded silicic ash-flow tuffs (Late Eocene to Middle Eocene)

WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS-Locally includes thin units of air-fall tuff and sedimentary rock

New York

Lamprophyre, trachyte, and rhyolite dikes (Jurassic - Lower Cretaceous)

Lamprophyre, trachyte, and rhyolite dikes - not shown in Proterozoic terrane.

Trachyte porphyry (Jurassic - Lower Cretaceous)

Trachyte porphyry - laccolith (?) at Cannon's Point near Willsboro, Essex County.

South Dakota

Phonolitic Intrusive Rocks (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)

Gray to greenish-gray sills, laccoliths, and small stocks of phonolite, trachyphonolite, and trachyandesite. Contains phenocrysts of andesine, feldspathoids, aegirine-augite, biotite, and sphene in a finely crystalline plagioclase-biotote-feldsphoid groundmass.

Trachytic Intrusive Rocks (Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene)

Tan to reddish-brown, iron-stained stocks, laccoliths, sills, and dikes of trachyte, quartz trachyte, and alkalic rhyolite. Contains phenocrysts of sanidine, orrthoclase, anorthoclase, aegirine-augite and biotite in a finely crystalline orthoclase-quartz biotite groundmass.

Texas

Bofecillos volcano volcanic rocks, including units 1-8 of Rawls Formation and lava flows in upper part of Fresno Formation (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Bofecillos volcano volcanic rocks, including units 1-8 of Rawls Formation and lava flows in upper part of Fresno Formation

Chinati Mountains caldera volcanic rocks, including Chinati Mountains Group, Mitchell Mesa Ignimbrite, and type area of Petan Basalt (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Chinati Mountains caldera volcanic rocks, including Chinati Mountains Group, Mitchell Mesa Ignimbrite, and type area of Petan Basalt

Delaho and Rawls Formations, undivided (Phanerozoic | Cenozoic | Tertiary | Oligocene Miocene)

Delaho and Rawls Formations, undivided NOTE: This unit is represented within the map unit explanation of (Geol. Map of Texas, 1992, Bur. Econ. Geol.) but does not occur on the map and is NOT included in the spatial data.

Duff Formation, Decie Member from Paisano caldera (Phanerozoic | Cenozoic | Tertiary | Oligocene-Early)

Duff Formation, Decie Member from Paisano caldera

Eagle Mountains caldera volcanic rocks (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Eagle Mountains caldera volcanic rocks

Eocene intrusive rocks (Phanerozoic | Cenozoic | Tertiary | Eocene)

Eocene intrusive rocks

Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Late)

Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation

older volcanic rocks of Davis and Barilla Mountains, including Sheep Pasture, Sleeping Lion, Frazier Canyon, Adobe Canyon, and Limpia formations, Gomez Tuff, Star Mountain Rhyolite, and Huelster Formation (Phanerozoic | Cenozoic | Tertiary | Eocene-Late)

older volcanic rocks of Davis and Barilla Mountains, including Sheep Pasture, Sleeping Lion, Frazier Canyon, Adobe Canyon, and Limpia formations, Gomez Tuff, Star Mountain Rhyolite, and Huelster Formation

Oligocene intrusive rocks (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Oligocene intrusive rocks

Quitman Mountains caldera volcanic rocks and volcanic rocks of sneed (Cox) Mountain and west of Victorio Peak (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Quitman Mountains caldera volcanic rocks and volcanic rocks of sneed (Cox) Mountain and west of Victoria Peak

Tarantula Gravel (Phanerozoic | Cenozoic | Tertiary | Miocene)

Tarantula Gravel

Tm2 and Tm3 units of Morita Ranch Formation (possibly from Cienega Mountain area) (Phanerozoic | Cenozoic | Tertiary | Oligocene)

Tm2 and Tm3 units of Morita Ranch Formation (possibly from Cienega Mountain area)

Van Horn Mountains caldera volcanic rocks (Phanerozoic | Cenozoic | Tertiary | Eocene)

Van Horn Mountains caldera volcanic rocks

Wiley Mountain caldera volcanic rocks (Phanerozoic | Cenozoic | Tertiary | Eocene)

Wiley Mountain caldera volcanic rocks

younger volcanic rocks of Davis Mountains area including Brooks Mountain, Goat Canyon, Medley, Barrel Springs, Wild Cherry, Eppenaurer Ranch, Mount Locke, and Merrill Formations (Phanerozoic | Cenozoic | Tertiary | Oligocene-Early)

younger volcanic rocks of Davis Mountains area including Brooks Mountain, Goat Canyon, Medley, Barrel Springs, Wild Cherry, Eppenaurer Ranch, Mount Locke, and Merrill Formations

Vermont

Bostonite (Permian-Triassic)

Bostonite - Many small leucophyres and lamprophyres do not show.