Bone Spring Formation
Geologic formation in Texas and New Mexico, US
From Wikipedia, the free encyclopedia
The Bone Spring Formation is a geologic formation found in the Delaware Basin in Texas and New Mexico. It preserves fossils dating back to the Leonardian Age of the Permian Period.[1]
| Bone Spring Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Underlies | Cutoff Shale |
| Thickness | 1,000 m (3,300 ft) |
| Lithology | |
| Primary | Limestone |
| Other | Shale, sandstone |
| Location | |
| Coordinates | 31.8508°N 104.9817°W |
| Region | Texas New Mexico |
| Country | United States |
| Type section | |
| Named for | Bone Spring Canyon |
| Named by | Blanchard and Davis |
| Year defined | 1929 |
  Bone Spring Formation (the United States)  Bone Spring Formation (Texas) | |
Description
The formation consists of dark gray deep marine limestone interbedded with shale and sandstone[1] interpreted as turbidites.[2] The total thickness is about 1,000 meters (3,300 ft). The base of the formation is largely concealed in the subsurface, and the formation is overlain by the Cutoff Shale.[1] The formation grades laterally into the Victorio Peak Formation.[3]
The uppermost shale beds of the formation have been assigned to the Avalon Shale.[4]
Fossils
The formation contains fossils of the brachiopods Productus leonardensis, Marginifera cristobalensis, Pugnoides texanus, P. bidentatus, and Composita mexicana; the ammonites Peritrochia erebus, Paracelites elegans, Agathiceras texanum, and Perrinites.[5]
History of investigation
The formation was first designated the Bone Springs Limestone by Blanchard and Davis in 1929.[6] It has subsequently been demoted to membership as the Bone Canyon Member of the Leonard Formation,[7] renamed the Bone Spring Limestone,[8] and most recently redesigned the Bone Spring Formation.[1] The Cutoff Shale was removed as a separate formation in 1964.[9]
Economic geology
The sandstones of the Bone Spring Formation are important petroleum reservoirs with estimated reserves in 1997 of 300,000–375,000 bbl.[10][11] The formation lies deep in the subsurface in the Delaware Basin, where its shale facies is known as the Avalon Shale.[12]
