La Pasada Formation | |
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Stratigraphic range: | |
![]() La Pasada Formation at its type section at Dalton's Bluff | |
Type | Formation |
Underlies | Alamitos Formation |
Overlies | Tererro Formation |
Thickness | 973 ft (297 m) |
Lithology | |
Primary | Limestone |
Other | Shale |
Location | |
Coordinates | 35°39′43″N105°41′35″W / 35.662°N 105.693°W |
Region | New Mexico |
Country | United States |
Type section | |
Named for | Upper La Pasada (abandoned Spanish settlement) |
Named by | P.K. Sutherland |
Year defined | 1963 |
The La Pasada Formation is a geologic formation in the southern Sangre de Cristo Mountains of New Mexico. It preserves fossils dating back to the early to middle Pennsylvanian. [1]
The formation is a cyclic carbonate consisting of alternating limestone and shale with some thin sandstones. Total thickness is 973–1,002 ft (297–305 m). The formation is more clastic towards its base (50% shale and siltstone) than towards its upper portion (24% shale and siltstone). The shales are noncalcareous and greenish towards the base but become gray, calcareous, and often fossiliferous towards the upper portion. The formation shows considerable lateral variability, grading into the Flechado Formation to the north. [1]
The lower half of the formation is interpreted as a shallow marine nearshore sequence with occasional nonmarine intervals with thin coal beds. The upper half was deposited under neritic offshore marine conditions with infrequent nonmarine intervals. [1]
The formation contains abundant fossils of Mesolobus and other brachiopods, fenestrate bryozoans, crinoid fragments, and less common pectinid bivalves, as well as small numbers of trilobites, including Ditomopyge scitula and Ameura missouriensis. [2]
The formation was first defined in 1963 by Patrick K. Sutherland, who considered it correlative with the lower part of the Madera Formation. [1] However, in 2004, Barry Kues and Katherine Giles recommended restricting the Madera Group to shelf and marginal basin beds of Desmoinean (upper Moscovian) to early Virgilian age, which excluded the La Pasada Formation. [3] Spencer G. Lucas and coinvestigators also exclude the La Pasada Formation from the Madera Group. [4]
The Bishop Cap Formation is a geologic formation in the Franklin Mountains of southern New Mexico and western Texas and the Hueco Mountains of western Texas. It preserves fossils dating back to the Moscovian to Kasimovian Ages of the early Pennsylvanian.
The San Andres Formation is a geologic formation found in New Mexico and Texas. It contains fossils characteristic of the late Leonardian (Kungurian) Age) of the Permian Period.
The Sangre de Cristo Formation is a geologic formation in Colorado and New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.
The Red House Formation is a geologic formation found in the Caballo Mountains in New Mexico. It preserves fossils dating back to the middle to late Pennsylvanian.
The Panther Seep Formation is a geologic formation found in the mountain ranges of south-central New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.
The Sandia Formation is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the early Pennsylvanian.
The Tererro Formation is a geologic formation in Sangre de Cristo Mountains of New Mexico. It preserves fossils dating back to the early Mississippian.
The Alamitos Formation is a geologic formation exposed in the southern Sangre de Cristo Mountains of New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian periods.
The Bursum Formation is a geologic formation in New Mexico. It preserves fossils dating back to the Early Permian period.
The Flechado Formation is a geologic formation in the northern Sangre de Cristo Mountains of New Mexico. It preserves fossils dating back to the early to middle 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 Berino Formation is a geologic formation in the Franklin Mountains of southern New Mexico and western Texas. It preserves fossils dating back to the middle Pennsylvanian.
The Onate Formation is a geologic formation that is exposed in most of the highlands of south-central New Mexico. It preserves fossils dating back to the middle Devonian period.
The Atrasado Formation is a geologic formation in New Mexico. Its fossil assemblage dates the formation to the Kasimovian age of the Pennsylvanian. It was formerly known locally as the Wild Cow Formation or the Guadelupe Box Formation.
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 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.
The La Tuna Formation is a geologic formation in the Franklin Mountains of southern New Mexico and western Texas and the Hueco Mountains of western Texas. It preserves fossils dating back to the Bashkirian Age of the early Pennsylvanian.
The Bar B Formation is a geologic formation found the Caballo Mountains of New Mexico. It preserves fossils showing it was deposited in the middle to late Pennsylvanian.
The Lead Camp Limestone is a geologic formation in the San Andres Mountains of New Mexico. It preserves fossils dating back to the middle Pennsylvanian.
The Gobbler Formation is a geologic formation in the Sacramento Mountains of New Mexico. It preserves fossils dating back to the Moscovian Age of the Pennsylvanian Period.