The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahua, Mexico, in the south. The rift zone consists of four basins that have an average width of 50 kilometres (31 mi). The rift can be observed on location at Rio Grande National Forest, White Sands National Park, Santa Fe National Forest, and Cibola National Forest, among other locations.
The Plains of San Agustin is a region in the southwestern U.S. state of New Mexico in the San Agustin Basin, south of U.S. Highway 60. The area spans Catron and Socorro Counties, about 50 miles (80 km) west of the town of Socorro and about 25 miles north of Reserve. The plains extend roughly northeast-southwest, with a length of about 55 miles (88 km) and a width varying between 5–15 miles (8–24 km). The basin is bounded on the south by the Luera Mountains and Pelona Mountain ; on the west by the Tularosa Mountains; on the north by the Mangas, Crosby, Datil, and Gallinas Mountains; and on the east by the San Mateo Mountains. The Continental Divide lies close to much of the southern and western boundaries of the plains.
The Acoma-Zuni Section is a physiographic section of the larger Colorado Plateaus province, which in turn is part of the larger Intermontane Plateaus physiographic division. It is bounded on the east by the Albuquerque Basin, a Rio Grande Rift basin in the northern part of the Basin and Range Province. The Datil-Mogollon Section lies to the south. It is also a newly defined physiographic unit that includes the northern part of the area previously designated the Datil Section. The southeastern edge of the Colorado Plateau from Springerville, Arizona, northeastward to the tip of the Sierra Nacimiento comprises this area.
The Nacimiento Formation is a sedimentary rock formation found in the San Juan Basin of western New Mexico. It has an age of 61 to 65.7 million years, corresponding to the early and middle Paleocene. The formation has yielded an abundance of fossils from shortly after the Cretaceous-Paleogene extinction event that provide clues to the recovery and diversification of mammals following the extinction event.
The Mogollon-Datil volcanic field is a large silicic volcanic field in western New Mexico. It is a part of an extensive Eocene to Oligocene volcanic event which includes the San Juan volcanic field in southwestern Colorado, the Trans-Pecos volcanic field in west Texas and north central Mexico, the Boot Heel volcanic field in the bootheel of southwestern New Mexico and adjacent areas of Arizona and Mexico; and the vast volcanic field of the Sierra Madre Occidental of western Mexico. The Mogollon-Datil volcanic field was formed in "four discrete pulses representing synchronized activity of two separate cauldron complexes".
The Caballo Mountains, are a mountain range located in Sierra and Doña Ana Counties, New Mexico, United States. The range is located east of the Rio Grande and Caballo Lake, and west of the Jornada del Muerto; the south of the range extends into northwest Doña Ana County. The nearest towns are Truth or Consequences and Hatch.
The Chamita Formation is a geologic formation in north-central New Mexico. It preserves unique fossils dating back to the Neogene period. The presence of volcanic ash beds in the formation, which can be radiometrically dated, gives the absolute age of the fossils, which is valuable for establishing the geologic time scale of the Neogene.
The Sierra Ladrones Formation is a geologic formation exposed near the Rio Grande Valley in New Mexico. It preserves fossils of Pliocene to Pleistocene age.
The Baca Formation is a geologic formation in southern New Mexico and Arizona. It preserves fossils dating back to the Eocene period.
The geology of New Mexico includes bedrock exposures of four physiographic provinces, with ages ranging from almost 1800 million years (Ma) to nearly the present day. Here the Great Plains, southern Rocky Mountains, Colorado Plateau, and Basin and Range Provinces meet, giving the state great geologic diversity.
The Santa Fe Group is a group of geologic formations in New Mexico and Colorado. It contains fossils characteristic of the Oligocene through Pleistocene epochs. The group consists of basin-filling sedimentary and volcanic rocks of the Rio Grande rift, and contains important regional aquifers.
The Tanos Formation is a geologic formation in central New Mexico. It is estimated to be about 25 million years in age, corresponding to the Oligocene epoch.
The Arroyo Ojito Formation is a late Miocene geologic formation exposed near Albuquerque, New Mexico. It records deposition of sediments in the Albuquerque Basin of the Rio Grande Rift after full integration of the Rio Grande through the basin.
The Blackshare Formation is a geologic formation exposed in the Hagan Basin west of the Ortiz Mountains of New Mexico. It is estimated be to of Miocene age.
The Spears Group is a group of geologic formations exposed in and around the northeast Mogollon-Datil volcanic field of southwestern New Mexico. It has a radiometric age of 33 to 39 million years, corresponding to the Eocene to Oligocene epochs.
The Cerro Conejo Formation is a middle to late Miocene geologic formation exposed near Albuquerque, New Mexico.
The Bell Top Formation is a geologic formation in southern New Mexico. Radiometric dating of surrounding tuffs indicate that it was deposited in the Oligocene epoch.
The Espanola basin is a structural basin in northern New Mexico. It is located in the Rio Grande watershed and is part of the Rio Grande rift. The definition of its boundaries is not fully settled, but the basin is usually defined such that it includes the cities of Santa Fe, Los Alamos, and Espanola.
Lake San Agustín is a former lake in New Mexico, which developed as a pluvial lake in the Plains of San Agustín during Pleistocene glacial periods. During its highstands it covered an area of 1,200 square kilometres (460 sq mi) with a maximum depth of 70 metres (230 ft), and split into several separate lakes while drying out. The lake last appeared during the last glacial maximum (LGM) and dried out at the beginning of the Holocene, with the last remnant disappearing about 5,000 years ago.
The Socorro Basin is a geographical feature in Socorro Co., New Mexico. It defines the transition where the Rio Grande Rift system broadens into a series of parallel basins separated by intra-rift horst blocks. Socorro Basin is hydraulically connected to rift basins to the north and south by flow-through drainage of the Rio Grande and southward flow of groundwater through alluvial sediments of the Rio Grande valley.
