Galisteo Formation | |
---|---|
Stratigraphic range: Duchesnean ~ | |
Type | Formation |
Underlies | Espinaso Formation |
Overlies | Diamond Tail Formation |
Area | Galisteo Basin |
Thickness | 979 m (3,212 ft) |
Lithology | |
Primary | Sandstone |
Other | Mudstone |
Location | |
Coordinates | 35°23′29″N105°58′36″W / 35.3914561°N 105.9767794°W |
Approximate paleocoordinates | 37°24′N97°24′W / 37.4°N 97.4°W |
Region | New Mexico |
Country | United States |
Type section | |
Named for | Galisteo Creek |
Named by | Hayden |
Year defined | 1869 |
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. [1]
The Galisteo Formation is primarily fluvial sandstone and mudstone, with small amounts of conglomerate, freshwater limestone, and sedimentary tuff. It crops out over a limited area between Sandia Crest and the southern Sangre de Cristo Mountains, with an outlier at the eastern feet of the San Miguel subrange of the Jemez Mountains. Its contact with the overlying Espinaso Formation is gradational. [2] The formation rests on the Diamond Tail Formation in most locations where its base is exposed, but the Diamond Tail is not present in the exposures south of San Ysidro. [3] The presence of Precambrian and Paleozoic clasts at the base of the Galisteo Formation suggests that the discontinuity separating it from the Diamond Tail is tectonic in origin. [4] There are indications the formation itself experienced penecontemporaneous deformation, possibly due to renewed uplift of the southern Sangre de Cristo Mountains. [2] The maximum thickness of the formation is 979 meters (3,212 feet). [3]
Paleocurrent directions indicate the sources of the sediments deposited in the formation came from the Brazos-Sangre de Cristo Geanticline to the northeast and the Nacimiento Mountains to the northwest. There are no indications of sediments from Sandia Crest to the south, suggesting that Sandia Crest was not uplifted until after the Eocene. [5] The presence of Precambrian clasts in the upper part of the formation in the San Miguel Mountains was some of the first evidence for the existence of the Pajarito Uplift, a Laramide structure occupying what is now the southern Espanola Basin between the current locations of Los Alamos and Santa Fe that later foundered into the Rio Grande Rift. [6]
The Galisteo Formation likely correlates with the El Rito Formation to the north of the Jemez Mountains. [6] It may also correlate with the Tapicito Member of the San Jose Formation. [7]
The most important fossil site in the Galisteo Formation, the Stearns quarry at Arroyo del Tuerto, [2] contains numerous fossil remains of titanotheres dating to the Duchesnean Stage, about 42 to 38 million years ago. Petrified wood is also found in this area. The formation is otherwise largely barren of fossils.
The following fossils have been reported from the formation: [1]
The formation was first described by F.V. Hayden during the 1869 expedition to New Mexico and Colorado. He named the formation the Galisteo sand group and noted that its sandstone beds dipped from 5 to 50 degrees and varied in color from off-white to brick red. He could find no fossils other than petrified logs, some of which were enormous. [11]
The formation originally included older beds separated from the rest of the formation by a significant disconformity. These were split off into the Diamond Tail Formation in 1997. [12]
The Sangre de Cristo Range is a mountain range in the Rocky Mountains in southern Colorado in the United States, running north and south along the east side of the Rio Grande Rift. The mountains extend southeast from Poncha Pass for about 75 mi (121 km) through south-central Colorado to La Veta Pass, approximately 20 mi (32 km) west of Walsenburg, and form a high ridge separating the San Luis Valley on the west from the watershed of the Arkansas River on the east. The Sangre de Cristo Range rises over 7,000 ft (2,100 m) above the valleys and plains to the west and northeast.
The Sierra Nacimiento, or Nacimiento Mountains, are a mountain range in the northwestern part of the U.S. state of New Mexico. They are just west of the more prominent Jemez Mountains near the town of Cuba, and are separated from them by the Río Guadalupe and the Río de Las Vacas. This article will consider them as a unit together with the San Pedro Mountains, which are a smaller range contiguous with the Sierra Nacimiento on the north, and which are also part of the Nacimiento Uplift and lie at the edge of the greater San Juan Basin, which sits atop the Colorado Plateau. The combined range runs almost due north-south with a length of about 40 mi (65 km). The highest point in the combined range is the high point of the San Pedro Peaks, known unofficially as San Pedro Peak, 10,605 ft.
The Hannold Hill Formation is an Early Eocene (Wasatchian) geologic unit in the western United States. It preserves the fossilized remains of the ray Myliobatis and gar.
The Wasatch Formation (Tw) is an extensive highly fossiliferous geologic formation stretching across several basins in Idaho, Montana, Wyoming, Utah and western Colorado. It preserves fossils dating back to the Early Eocene period. The formation defines the Wasatchian or Lostcabinian, a period of time used within the NALMA classification, but the formation ranges in age from the Clarkforkian to Bridgerian.
The Sandia Formation is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the early Pennsylvanian.
The Gray Mesa Formation is a geologic formation in New Mexico. Its fossil assemblage dates the formation to the Moscovian age of the Pennsylvanian.
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 Palm Park Formation is a geologic formation in southern New Mexico. It preserves fossils dating back to the Eocene epoch.
The San Jose Formation is an Early Eocene geologic formation in the San Juan Basin of New Mexico and Colorado.
The Yeso Group is a group of geologic formations in New Mexico. It contains fossils characteristic of the Kungurian Age of the early Permian Period.
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 Las Tetas de Cabra Formation is a geologic formation in Mexico. It preserves fossils dating back to the Wasatchian of the Early 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 Log Springs Formation is a geologic formation in the Jemez, Nacimiento, and Sandia Mountains of New Mexico. Its age is poorly constrained but is thought to be Namurian.
The Diamond Tail Formation is a geologic formation in New Mexico. It contains fossils characteristic of the late Paleocene or early Eocene.
The El Rito Formation is a geologic formation in New Mexico dating to the Eocene epoch. It records a time when sediments were trapped in deep basins in western North America rather than being carried downstream to the Gulf of Mexico, so that sediments of this age in the western Gulf are mostly from the Appalachian Mountains.
The Tuerto Formation is a geologic formation exposed around the Ortiz Mountains of New Mexico. It is estimated to be of Pliocene to Pleistocene age, and forms the gravel cap of the Ortiz surface, one of the first pediment surfaces recognized by geologists.
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 Love Ranch Formation is a geologic formation in southern New Mexico. It was likely deposited during the late Paleocene and early Eocene epochs.
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.