Trujillo Formation | |
---|---|
Stratigraphic range: Late Triassic, | |
Type | Formation |
Unit of | Dockum Group |
Overlies | Tecovas Formation |
Thickness | 45–210 feet (14–64 m) |
Lithology | |
Primary | Sandstone |
Other | conglomerate, mudstone |
Location | |
Coordinates | 35°15′00″N103°01′54″W / 35.2501°N 103.0318°W |
Region | Texas New Mexico |
Country | United States |
Type section | |
Named for | Trujillo Creek |
Named by | C.N. Gould |
Year defined | 1907 |
The Trujillo Formation is a geologic formation in Texas [1] and New Mexico. [2] It preserves fossils dating back to the upper Triassic period. [2] It is also known as the Trujillo Sandstone.
The formation consists mostly of gray to brown or red sandstone, but with some conglomerate and mudstone. Conglomerate is more common in the middle beds while mudstone is more common in the middle and upper beds. The sandstone is typically crossbedded and is fine-grained in the lower beds and more coarse in the middle and upper beds. The lower sandstone beds tend to form a prominent cliff. The total thickness varies from 45–210 feet (14–64 m). The formation overlies the Tecovas Formation. [1]
The Cuervo Sandstone Member is preempted by the Trujillo Formation. [3]
The formation crops out along Palo Duro Canyon and the Canadian River and their tributaries. [1] It is also widespread in the Sangre de Cristo Mountains. [4]
The formation is interpreted as deposition in a braided stream system. [5] The lower beds at Palo Duro Canyon contain unusual cone-shaped iron concretions that likely formed in the vadose zone. [6]
The formation contains Typothorax scutes [7] and the unusual cycad Sanmiguelia . [8]
The formation was first named as the upper formation of the Dockum Group in 1907 by C.N. Gould. [1]
Palo Duro Canyon is a canyon system of the Caprock Escarpment located in the Texas Panhandle near the cities of Amarillo and Canyon. As the second-largest canyon in the United States, it is roughly 120 mi (190 km) long and has an average width of 6 mi (9.7 km), but reaches a width of 20 mi (32 km) at places. Its depth is around 820 ft (250 m), but in some locations, it increases to 1,000 ft (300 m). Palo Duro Canyon has been named "The Grand Canyon of Texas" both for its size and for its dramatic geological features, including the multicolored layers of rock and steep mesa walls, which are similar to those in the Grand Canyon. It is part of Palo Duro Canyon State Park.
The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone, and limestone and is light gray, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.
The Moenkopi Formation is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this red sandstone was laid down in the Lower Triassic and possibly part of the Middle Triassic, around 240 million years ago.
The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In New Mexico, it is often raised to the status of a geological group, the Chinle Group. Some authors have controversially considered the Chinle to be synonymous to the Dockum Group of eastern Colorado and New Mexico, western Texas, the Oklahoma panhandle, and southwestern Kansas. The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains. A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. The southern portion of the Chinle reaches a maximum thickness of a little over 520 meters (1,710 ft). Typically, the Chinle rests unconformably on the Moenkopi Formation.
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much thinner. The Dockum rests on an unconformity over the Anisian aged Anton Chico Formation.
The Garita Creek Formation is a geologic formation in New Mexico that contains vertebrate fossils characteristic of the Carnian Age of the late Triassic.
The Moenave Formation is a Mesozoic geologic formation, in the Glen Canyon Group. It is found in Utah and Arizona.
The Santa Rosa Formation is a geologic formation exposed in New Mexico that was deposited in the Carnian Age of the late Triassic Period.
The Shinarump Conglomerate is a geologic formation found in the Four Corners region of the United States. It was deposited in the early part of the Late Triassic period.
The Baldy Hill Formation is a geologic formation in northeastern New Mexico and western Oklahoma. It preserves fossils dating back to the late Triassic period.
The Sandia Formation is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the early Pennsylvanian.
The Del Norte Formation is a geologic formation in Mexico, New Mexico and Texas near the city of El Paso. It preserves fossils dating back to the early Cretaceous period.
The Cub Mountain Formation is a geologic formation in southern New Mexico. It preserves fossils dating back to the Eocene epoch. The formation also records the progressive unroofing of nearby mountainous uplifts during the Laramide orogeny.
The Galisteo Formation is a geologic formation in New Mexico. It contains fossils characteristic of the Bartonian stage of the Eocene epoch, Duchesnean in the NALMA classification.
The Salitral Formation is a Late Triassic geologic formation found in north-central New Mexico, primarily the northwestern Jemez Mountains. It is an older subunit of the Chinle Group, overlying the Shinarump Conglomerate and underlying the Poleo Formation.
The San Pedro Arroyo Formation is a geologic formation in south-central New Mexico. It preserves fossils dating back to the late Triassic period.
The Rock Point Formation is a geologic formation in New Mexico, Arizona, and Utah. It preserves fossils dating back to the late Triassic.
The Madera Group is a group of geologic formations in northern New Mexico. Its fossil assemblage dates the formation to the middle to late Pennsylvanian period.
The Diamond Tail Formation is a geologic formation in New Mexico. It contains fossils characteristic of the late Paleocene or early Eocene.
The Porvenir Formation is a geologic formation exposed in the southeastern Sangre de Cristo Mountains of New Mexico. It preserves fossils dating back to the middle Pennsylvanian period.