| Flechado Formation | |
| Type: | Formation |
| Prilithology: | Sandstone, shale |
| Otherlithology: | Siltstone, limestone, conglomerate |
| Namedfor: | Flechado Creek |
| Namedby: | P.K. Sutherland |
| Year Ts: | 1963 |
| Region: | New Mexico |
| Country: | United States |
| Coordinates: | 36.1624°N -105.5786°W |
| Underlies: | Alamitos Formation |
| Overlies: | Tererro Formation |
| Thickness: | 2500feet |
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 Flechado Formation consists of low-feldspar sandstone and shale alternating with thin beds of limestone. The total thickness is 2500feet. It overlies the Tererro Formation and is overlain by the Alamitos Formation. The formation is well to extremely well cemented in the type area, so that it can be difficult to distinguish from the Precambrian Ortega Formation.
The formation grades laterally into the La Pasada Formation to the south of the Rio Pueblo, with the clastic beds of the Flechado abruptly thinning and transitioning to carbonate beds of the La Pasada over a distance of about 5miles.
The terrigenous sediments of the Flechado Formation were likely derived from the southern part of Uncompahgre uplift during uplift on the west side of the Picuris-Pecos fault.
Fossils are scarce in the upper portion of the Flechado Formation, but middle Desmoinesian (upper Moscovian) brachiopods are found about 800feet below the top of the formation. Atokan (lower Moscovian) fusulinids andbrachiopods are found in the lower part, which also contains broken crinoid, bryozoan, and algal remains.
The formation was first described by P.K. Sutherland in 1963.