Geologic units in Hidalgo county, New Mexico

Additional scientific data in this geographic area

Piedmont alluvial deposits (Holocene to lower Pleistocene) at surface, covers 42 % of this area

Includes deposits of higher gradient tributaries bordering major stream valleys, alluvial veneers of the piedmont slope, and alluvial fans. May locally include uppermost Pliocene deposits.

Alluvium (Holocene to upper Pleistocene) at surface, covers 13 % of this area

Alluvium

Lower middle Tertiary rhyolitic to dacitic pyroclastic rocks of the Datil Group, ash-flow tuffs (Lower Oligocene to upper Eocene (31-36 Ma)) at surface, covers 10 % of this area

Regional ash-flow tuffs include Hell's Mesa, Kneeling Nun, Caballo Blanco, Datil Well, Leyba Well, Rock House Canyon, Blue Canyon, Sugarlump, Oak Creek, Bluff Creek, Gillespie, Box Canyon, Cooney and Chiquito Peak Tuffs; the tuffs of Steins Mountain, Black Bill Canyon, Woodhaul Canyon, and Farr Ranch; tuffs of the Organ cauldron; and lower tuffs in the Bell Top Formation. Includes some locally erupted lavas and tuffs within thick intra-caldera units; includes minor volcaniclastic sedimentary units and lavas between thin outflow sheets.

Gila Group, Formation, or Conglomerate (Middle Pleistocene to uppermost Oligocene?) at surface, covers 6 % of this area

Includes Mimbres Formation and several informal units in southwestern basins.

Lacustrine and playa-lake deposits (Holocene) at surface, covers 5 % of this area

Includes associated alluvial and eolian deposits of major lake basins.

Upper middle Tertiary rhyolitic lavas and local tuffs (Upper Oligocene (24-29 Ma)) at surface, covers 3 % of this area

Includes Taylor Creek Rhyolite, Fanney Rhyolite, rhyolite of Rocky Canyon, rhyolite of Hardy Ridge, and upper rhyolite members of the Luis Lopez and Sawmill Canyon formations.

Middle Tertiary volcaniclastic sedimentary units (Oligocene to upper Eocene) at surface, covers 2 % of this area

Mostly syneruptive volcaniclastic sedimentary aprons. Lower units dominantly derived from volcanic highlands of andesitic to dacitic composition. Locally includes minor lavas and tuffs. Younger units (above and intertongued with Mogollon Group tuffs, Turp) include upper Bell Top Formation, South Crosby Peak Formation, and upper Spears Group units near Quemado. Older units (below and intertongued with Datil Group tuffs, Tlrp) include Palm Park, lower Bell Top, Espinaso and Pueblo Creek Formatios and lower Spears Group formations such as Rincon Windmill, Chavez Canyon, and Dog Springs.

Lower middle Tertiary volcanic rocks (Lower Oligocene to upper Eocene (older than 31 Ma)) at surface, covers 2 % of this area

Mostly intermediate lavas of the lower Datil Group and intermediate volcaniclastic sediments of the lower Spears Group (Tla+Tvs). Locally includes ash-flow tuffs of the upper Datil Group (Tlrp). Includes intermediate volcaniclastic sedimentary rocks of the Conejos Formation in northern New Mexico.

Older piedmont alluvial deposits and shallow basin fill (Middle Pleistocene to uppermost Pliocene) at surface, covers 2 % of this area

Includes Quemado Formation and in northeast, high-level pediment gravels.

Upper middle Tertiary rhyolitic pyroclastic rocks of the Mogollon Group, ash-flow tuffs (Upper Oligocene (24-30 Ma)) at surface, covers 2 % of this area

Regional ash-flow tuffs include the La Jencia, Vick's Peak, Lemitar, South Canyon, Bloodgood Canyon, Shelley Peak, Davis Canyon, Park, Rhyolite Canyon, Apache Springs, and Amalia Tuffs; the tuffs of Horseshoe Canyon, Diamond Creek, Garcia Camp, Caronita Canyon, Turkey Springs, and Little Mineral Creek; and the Jordan Canyon Formation. Includes some locally erupted lavas and tuffs within thick intra-caldera units; includes minor volcaniclastic sedimentary units between thin outflow sheets.

Lower middle Tertiary andesitic to dacitic lavas and pyroclastic flow breccias (Upper to middle Eocene (33-43 Ma)) at surface, covers 2 % of this area

Includes Rubio Peak Formation, Orejon Andesite, andesite of Dry Leggett Canyon, andesite of Telephone Canyon, and other units in southwestern, central, and northern New Mexico. Locally includes minor mafic lavas. Ancient landslide blocks of Mader Limestone, as much as one mile long, occur within Rubio Peak lavas in the central Black Range, west of Winston.

Eolian deposits (Holocene to middle Pleistocene) at surface, covers 1 % of this area

Eolian deposits.

Upper middle Tertiary volcanic rocks (Lower Miocene to upper Oligocene (younger than 30 Ma)) at surface, covers 1 % of this area

Mostly a combination of basaltic andesite lavas and rhyolitic ash-flow tuffs of the Mogollon Group (Tuau+Tual+Turp). Includes locally erupted lavas and tuffs in some calderas.

Lower Cretaceous, undivided (Lower Cretaceous) at surface, covers 1 % of this area

In northern Lea and Roosevelt Counties includes equivalents of Tucumcari Shale; in Cornudas Mountains includes Campogrande and Cox Formations and Washita Group; at Cerro de Cristo Rey includes several formations of the Fredricksburg and Washita Groups, and the Boquillas Formation (Cenomanian); in the southwest includes Mojado, U-Bar (Aptian), and Hell-to-Finish Formations, whch are equivalent to Bisbee Group of Arizona.

Permian and Pennsylvanian rocks, undivided (Permian and Pennsylvanian) at surface, covers 1 % of this area

Includes Concha, Scherrer, Colina, Epitaph, and Earp Formations (Permian) and Horquilla Limestone (Permian to Pennsylvanian).

Lower middle Tertiary rhyolitic lavas and local tuffs (Lower Oligocene to upper Eocene (31-36 Ma)) at surface, covers 1 % of this area

Includes Mimbres Peak Formation, rhyolite of Cedar Hills, and other units in the Bootheal region.

Tertiary-Cretaceous andesitic to dacitic lavas and pyroclastic breccias (Paleocene and upper Cretaceous) at surface, covers 0.9 % of this area

Includes many remnants of eruptive centers in Grant and Hidalgo Counties and Upper Creatceous andesitic lavas in Sierra County.

Basaltic to andesitic lava flows (Holocene to middle Pleistocene) at surface, covers 0.7 % of this area

Flows south of Grants and west of Carrizozo are Holocene. Includes minor vent deposits.

Mesoproterozoic granitic plutonic rocks (Mesoproterozoic) at surface, covers 0.6 % of this area

Mainly 1.45 - 1.35 Ga megacrystic granites, generally weakly foliated except locally at their margins.

Tertiary-Cretaceous intrusive rocks (Paleocene and upper Cretaceous) at surface, covers 0.5 % of this area

Includes granodiorite to quartz monzonite stocks and plutons at Hanover, Fierro, Tyrone, Lordsburg, and the 73 Ma quartz monzonite porphyry stock at Copper Flatsin Sierra County. Also includes many norhteast-trending monzonite porphyry dikes in the Silver City region.

Permian rocks, undivided (Permian) at surface, covers 0.4 % of this area

Permian rocks, undivided

Tertiary intrusive rocks of intermediate to silicic composition (Pliocene to Eocene) at surface, covers 0.4 % of this area

Includes monzonitic to granitic plutons, stocks, laccoliths, and porphyritic dikes in deeply eroded magmatic centers; and andesitic, dacitic, or rhyolitic plugs and dikes near cauldrons or stratovolcanoes. In the Latir field, fine-grained rhyolitic dikes commonly cut coarse-grained granitic plutons. Includes alkaline laccoliths, plugs, and dikes in Colfax County. North-trending dikes near Capitan include some mafic diabase dikes.

Basaltic to andesitic lava flows (Neogene) at surface, covers 0.4 % of this area

Includes minor vent deposits. Flows are commonly interbedded in the Santa Fe and Gila Groups.

Mancos Shale and Beartooth and Sarten Formations (Cenomanian and Albian) at surface, covers 0.3 % of this area

Mancos includes what was formerly referred to as Colorado Shale, which in turn may include equivalents of Tres Hermanos Formation.

Lower-upper middle Tertiary basaltic andesites and andesites of the Mogollon Group (Upper Oligocene (26-29 Ma)) at surface, covers 0.2 % of this area

Includes La Jara Peak Basaltic Andesite, Uvas Basaltic Andesite, basaltic andesites of Poverty Creek and Twin Peaks, Squirrel Springs Canyon Andesite, Razorback Basalt, Bear Springs Basalt, flows of Gila Flat, Salt Creek Formation, Middle Mountain Formation, and the Alum Mountain Group. Pre-Amalia-Tuff lavas in the Questa caldera are dominantly silicic andesites and dacites; elsewhere silicic lavas are a minor component of Tual.

Upper middle Tertiary basaltic andesites and andesites of the Mogollon Group (Lower Miocene and uppermost Oligocene (22-26 Ma)) at surface, covers 0.2 % of this area

Includes Bearwallow Mountain Andesite and basaltic andesite of Mangas Mountain; also near vent basaltic lavas and shallow intrusions in the Chuska Mountains.

Upper Cretaceous rocks of southwestern New Mexico, undivided (Maastrichtian to Cenomanian) at surface, covers 0.2 % of this area

Beartooth and Sarten Formations are in part Albian. Includes Virden Formation in northern Hidalgo County, Ringbone Formation in Hidalgo, Luna and Grant Counties, Mancos Shale in Silver City area.

Ordovician and Cambrian rocks, undivided (Ordovician and Cambrian) at surface, covers 0.2 % of this area

Includes Montoya Formation (or Group), El Paso Formation, and Bliss Sandstone.

Upper and Middle Jurassic rocks, undivided (Upper and Middle Jurassic) at surface, covers 0.1 % of this area

In southwest includes the basalt-bearing Broken Jug Formation.

Paleoproterozoic metasedimentary rocks (Paleoproterozoic) at surface, covers 0.1 % of this area

Pelitic schist, quartz-muscovite schist, immature quartzite, and subordinate amphibolite; includes parts of Vadito Group in northern New Mexico, immature metasedimentary rocks of central New Mexico, and Bullard Peak Series mixed supracrustal rocks in Burro Mountains.

Paleogene sedimentary units (Paleogene) at surface, covers 0.1 % of this area

Includes Baca, Galisteo, El Rito, Blanco Basin, Hart Mine, Love Ranch, Lobo, Sanders Canyon, Skunk Ranch, Timberlake, and Cub Mountain Formations.

Mississippian and Devonian rocks, undivided (Mississippian and Devonian) at surface, covers < 0.1 % of this area

Includes Helms, Rancheria, Las Cruces, Lake Valley, and Caballero Formations and Escabrosa Group (Mississippian); Percha Shale, Contadero, Sly Gap, and Onate Formations of south-central New Mexico, and Canutillo Formation of northern Franklin Mountains and Bishops Cap area (Devonian).

Paleozoic rocks, undivided (Paleozoic) at surface, covers < 0.1 % of this area

Paleozoic rocks, undivided

Mississippian rocks, undivided (Mississippian) at surface, covers < 0.1 % of this area

Arroyo Penasco Group in Sangre de Cristo Mountains, Sierra Nacimiento, San Pedro Mountain, and Sandia Mountains; Lake Valley Limestone in south-central New Mexico.

Basaltic to andesitic lava flows (Pliocene) at surface, covers < 0.1 % of this area

Includes minor vent deposits and small shield volcanoes. Flows are commonly interbedded in the Santa Fe and Gila Groups.

Quaternary surficial deposits, undivided (Quaternary) at surface, covers < 0.1 % of this area

Unconsolidated to strongly consolidated alluvial and eolian deposits. This unit includes: coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits. (0-2 Ma)

Mississippian through Cambrian rocks, undivided (Mississippian through Cambrian) at surface, covers < 0.1 % of this area

Includes Lake Valley Limestone (Mississippian); Devonian rocks, undivided; El Paso Formation and Montoya Group or Formation (Ordovician); and Bliss Sandstone (Cambrian and Ordovician).

Middle Miocene to Oligocene volcanic rocks (Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

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)

Silurian through Cambrian rocks, undivided (Silurian through Cambrian) at surface, covers < 0.1 % of this area

Silurian through Cambrian rocks, undivided

Late and middle Pleistocene surficial deposits (Middle to Late Pleistocene) at surface, covers < 0.1 % of this area

Unconsolidated to weakly consolidated alluvial fan, terrace, and basin-floor deposits with moderate to strong soil development. Fan and terrace deposits are primarily poorly sorted, moderately bedded gravel and sand, and basin-floor deposits are primarily sand, silt, and clay. (10-750 ka)