Geologic units in Sierra county, New Mexico

Additional scientific data in this geographic area

Upper Santa Fe Group (Middle Pleistocene to uppermost Miocene) at surface, covers 31 % of this area

Includes Camp Rice, Fort Hancock, Palomas, Sierra Ladrones, Arroyo Ojito, Ancha, Puye, and Alamosa Formations.

Piedmont alluvial deposits (Holocene to lower Pleistocene) at surface, covers 9 % 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.

Eolian deposits (Holocene to middle Pleistocene) at surface, covers 8 % of this area

Eolian deposits.

Pennsylvanian rocks, undivided (Pennsylvanian) at surface, covers 6 % of this area

In Sangre de Cristo Mountains may include Sandia, Madera, La Pasada, Alamitos, and Flechado Formations; elsewhere may include Bar-B, Nakaye, Red House, Oswaldo, and Syrena Formations.

Lower middle Tertiary andesitic to dacitic lavas and pyroclastic flow breccias (Upper to middle Eocene (33-43 Ma)) at surface, covers 4 % 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.

Upper middle Tertiary rhyolitic pyroclastic rocks of the Mogollon Group, ash-flow tuffs (Upper Oligocene (24-30 Ma)) at surface, covers 4 % 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 rhyolitic to dacitic pyroclastic rocks of the Datil Group, ash-flow tuffs (Lower Oligocene to upper Eocene (31-36 Ma)) at surface, covers 3 % 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.

Alluvium (Holocene to upper Pleistocene) at surface, covers 3 % of this area

Alluvium

Lower Santa Fe Group (Upper Miocene to uppermost Oligocene) at surface, covers 2 % of this area

Includes Hayner Ranch, Rincon Valley, Popotosa, Cochiti, Tesuque, Chamita, Abiquiu, Zia, and other formations.

Lower-upper middle Tertiary basaltic andesites and andesites of the Mogollon Group (Upper Oligocene (26-29 Ma)) at surface, covers 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 rhyolitic lavas and local tuffs (Upper Oligocene (24-29 Ma)) at surface, covers 2 % 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.

Yeso Formation (Leonardian) at surface, covers 2 % of this area

Sandstones, siltstones, anhydrite, gypsum, halite, and dolomite.

Abo Formation (Wolfcampian) at surface, covers 2 % of this area

Red beds, arkosic at base, finer and more mature above; Wolfcampian; may include limestone beds of Pennsylvanian age (Virgilian) in Zuni Mountains. In Robledo Mountains the Abo may be considered a member of the Hueco Formation.

Mesaverde Group (Campanian to Turonian) at surface, covers 2 % of this area

Includes Cliff House Sandstone, Menefee Formation, and Point Lookout Sandstone.

Upper middle Tertiary volcanic rocks (Lower Miocene to upper Oligocene (younger than 30 Ma)) at surface, covers 2 % 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.

San Andres Formation (Guadalupian and Leonardian) at surface, covers 2 % of this area

Limestone and dolomite with minor shale. Guadalupian in south, in part Leonardian to north.

Lower middle Tertiary volcanic rocks (Lower Oligocene to upper Eocene (older than 31 Ma)) at surface, covers 1 % 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.

Gila Group, Formation, or Conglomerate (Middle Pleistocene to uppermost Oligocene?) at surface, covers 1 % of this area

Includes Mimbres Formation and several informal units in southwestern basins.

Basaltic to andesitic lava flows (Pliocene) at surface, covers 1 % of this area

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

Middle Tertiary volcanic rocks, undifferentiated (Lower Miocene to upper Eocene) at surface, covers 1 % of this area

Includes the predominantly andesitic to dacitic stratovolcano complex at Sierra Blanca (Oligocene to upper Eocene) and many smaller outliers.

Mississippian through Cambrian rocks, undivided (Mississippian through Cambrian) at surface, covers 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).

Lacustrine and playa-lake deposits (Holocene) at surface, covers 0.9 % of this area

Includes associated alluvial and eolian deposits of major lake basins.

Mesoproterozoic granitic plutonic rocks (Mesoproterozoic) at surface, covers 0.8 % of this area

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

Madera Group (Pennsylvanian) at surface, covers 0.8 % of this area

In Manzano Mountains includes Wild Cow Formation and Los Moyos Limestone; in Lucero Mesa includes Red Tanks, Atrasado, Gray Mesa Formations; in Sacramento Mountains includes the non-Madera Holder, Beeman and Gobbler Formations. May include strata lumped as Magdalena Group in a few areas.

Tertiary intrusive rocks of intermediate to silicic composition (Pliocene to Eocene) at surface, covers 0.7 % 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.

Paleogene sedimentary units (Paleogene) at surface, covers 0.7 % of this area

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

Basaltic to andesitic lava flows (Holocene to middle Pleistocene) at surface, covers 0.6 % of this area

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

Middle Tertiary volcaniclastic sedimentary units (Oligocene to upper Eocene) at surface, covers 0.6 % 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.

McRae Formation (Maastrichtian) at surface, covers 0.6 % of this area

Engle basin - Cutter sag area.

Santa Fe Group, undivided (Middle Pleistocene to uppermost Oligocene) at surface, covers 0.5 % of this area

Basin fill of the Rio Grande rift. Locally represents upper Miocene formations of the middle Santa Fe Group in the northern Albuquerque Basin.

Hueco Formation or Group (Wolfcampian) at surface, covers 0.5 % of this area

Limestone unit restricted to south-central area; Pendejo Tongue of Hueco Formation divides Abo Formation into upper and lower parts in Sacramento Mountains.

Lower middle Tertiary rhyolitic lavas and local tuffs (Lower Oligocene to upper Eocene (31-36 Ma)) at surface, covers 0.5 % of this area

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

Silurian through Cambrian rocks, undivided (Silurian through Cambrian) at surface, covers 0.5 % of this area

Silurian through Cambrian rocks, undivided

Silicic to intermediate volcanic rocks (Neogene, mostly Miocene) at surface, covers 0.4 % of this area

Rhyolite and dacite flows with associated minor tuffs. Commonly interbedded with Santa Fe or Gila Group sedimentary units. Dacitic lavas in northern Jemez Mountains are Pliocene.

Paleoproterozoic granitic plutonic rocks (Paleoproterozoic) at surface, covers 0.3 % of this area

Variably foliated granites and granitic gneisses; 1.71 - 1.65 Ga in northern New Mexico; 1.66 - 1.65 Ga in central and southern New Mexico.

Permian rocks, undivided (Permian) at surface, covers 0.3 % of this area

Permian rocks, undivided

Tertiary-Cretaceous andesitic to dacitic lavas and pyroclastic breccias (Paleocene and upper Cretaceous) at surface, covers 0.3 % of this area

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

Paleoproterozoic mafic metavolcanic rocks with subordinate felsic metavolcanic rocks (Paleoproterozoic) at surface, covers 0.3 % of this area

Includes the 1.78-1.72 Ga Moppin (Tusas Mountains), Gold Hill (Taos Range), and Pecos (Sangre de Cristo Mountains) complexes; interpreted to be supracrustal part of juvenile volcanic arc basement.

Upper Cretaceous rocks of southwestern New Mexico, undivided (Maastrichtian to Cenomanian) at surface, covers 0.3 % 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.

San Andres, Glorieta, and Yeso Formations, undivided (Guadalupian and Leonardian) at surface, covers 0.3 % of this area

San Andres, Glorieta, and Yeso Formations, undivided

Mancos Shale (Cenomanian to Campanian) at surface, covers 0.2 % of this area

Divided into Upper and Lower parts by Gallup Sandstone.

Paleozoic rocks, undivided (Paleozoic) at surface, covers 0.2 % of this area

Paleozoic rocks, undivided

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.

Upper middle Tertiary basaltic andesites and andesites of the Mogollon Group (Lower Miocene and uppermost Oligocene (22-26 Ma)) at surface, covers 0.1 % 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.

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).

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

Includes minor vent deposits.

Permian and Pennsylvanian rocks, undivided (Permian and Pennsylvanian) at surface, covers < 0.1 % of this area

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

Paleoproterozoic quartzite (Paleoproterozoic) at surface, covers < 0.1 % of this area

Includes 1.70 Ga Ortega Quartzite and equivalents in northern New Mexico and 1.67 Ga quartzites in central New Mexico.

Gypsiferous eolian deposits (Holocene to middle Pleistocene) at surface, covers < 0.1 % of this area

Gypsiferous eolian deposits.

Dakota Sandstone (Cenomanian) at surface, covers < 0.1 % of this area

Includes Oak Canyon, Cubero, and Paguate Tongues; includes Clay Mesa Tongue of Mancos Shale.

Tertiary-Cretaceous intrusive rocks (Paleocene and upper Cretaceous) at surface, covers < 0.1 % 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.

Landslide deposits and colluvium (Holocene to Pleistocene) at surface, covers < 0.1 % of this area

Landslide deposits on western flanks of Socorro Mountains not shown for clarity.

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

Includes Percha Shale, Onate and Sly Gap Formations.

Intertongued Mancos Shale and Dakota Sandstone of west-central New Mexico (Cenomanian) at surface, covers < 0.1 % of this area

Includes the Whitewater Arroyo Tongue of Mancos Shale and the Twowells Tongue of the Dakota.

Silurian and Ordovician rocks, undivided (Silurian and Ordovician) at surface, covers < 0.1 % of this area

Silurian and Ordovician rocks, undivided

Paleoproterozoic rhyolite and felsic volcanic schist (Paleoproterozoic) at surface, covers < 0.1 % of this area

Includes 1.70 Ga Vadito Group in northern New Mexico and 1.68 Ga Sevilleta Metarhyolite in central New Mexico.

Ordovician and Cambrian rocks, undivided (Ordovician and Cambrian) at surface, covers < 0.1 % of this area

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

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

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

Older piedmont alluvial deposits and shallow basin fill (Middle Pleistocene to uppermost Pliocene) at surface, covers < 0.1 % of this area

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

Bursum Formation (Lowermost Permian to uppermost Pennsylvanian) at surface, covers < 0.1 % of this area

Shale, arkose, and limestone.

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

Cretaceous rocks, undivided

Artesia Group (Guadalupian) at surface, covers < 0.1 % of this area

Shelf facies forming broad south-southeast trending outcrop from Glorieta to Artesia area; includes Tansill, Yates, Seven Rivers, Queen and Grayburg Formations (Guadalupian). May locally include Moenkopi Formation (Triassic) at top.

Tertiary mafic intrusive rocks (Pliocene to upper Eocene) at surface, covers < 0.1 % of this area

Includes many long basaltic andesite dikes of Oligocene age near Pie Town, Acoma, Riley, Chupadera, Truth or Consequences, Roswell, Raton, and Dulce; and several elongate or shoestring-like sills of basalt or basaltic andesite. Also includes basaltic necks of Pliocene age that dot the landscape northeast of Mount Taylor. Where dikes extend into Quaternary alluvium the contact is an unconformity.