Earth:Bone Spring Formation

From HandWiki
Bone Spring Formation
Stratigraphic range: Kungurian
TypeFormation
UnderliesCutoff Shale
Thickness1,000 m (3,300 ft)
Lithology
PrimaryLimestone
OtherShale, sandstone
Location
Coordinates [ ⚑ ] 31°51′03″N 104°58′54″W / 31.8508°N 104.9817°W / 31.8508; -104.9817
RegionTexas
New Mexico
CountryUnited States
Type section
Named forBone Spring Canyon
Named byBlanchard and Davis
Year defined1929
Lua error in Module:Location_map/multi at line 27: Unable to find the specified location map definition: "Module:Location map/data/Texas" does not exist.

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]

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]

See also

  • List of fossiliferous stratigraphic units in New Mexico
  • List of fossiliferous stratigraphic units in Texas


Footnotes

References