Tansill Formation

The Tansill Formation is a geologic formation in southeastern New Mexico and west Texas, United States.^[1] It preserves fossils dating back to the late Guadalupian Age of the Permian period.^[2]

Tansill Formation
Stratigraphic range: Guadalupian PreꞒ Ꞓ O S D C P T J K Pg N
Yates (yellow sandstone) and Tansill (white limestone)
Type	Formation
Unit of	Artesia Group
Overlies	Yates Formation
Thickness	123–320 feet (37–98 m)
Lithology
Primary	Limestone, siltstone, anhydrite
Location
Coordinates	32.448°N 104.265°W / 32.448; -104.265
Region	New Mexico
Country	United States
Type section
Named for	Tansill power dam
Named by	DeFord et al.
Year defined	1938
Tansill Formation (the United States) Show map of the United States Tansill Formation (New Mexico) Show map of New Mexico

Description

Tansill Formation exposed at Rattlesnake Canyon as viewed from the trailhead, Carlsbad National Park

The formation consists of limestone, siltstone, and anhydrite that is extensive in the subsurface in southeastern New Mexico and west Texas. The formation is mostly limestone in the south and west, around the rim of the Delaware Basin, and grades into anhydrite in the north and east. It forms the top of the Capitan reef but dips steeply into the subsurface.^[3] It has a total thickness of 123–320 feet (37–98 m).^[3][4] It overlies the Yates Formation.^[5] The formation is part of the Artesia Group, which is interpreted as a shelf rock sequence.^[2]

History of investigation

The formation was first named by DeFord et al. in 1938^[1] and formally defined in 1941 and assigned to the (now abandoned) Whitehorse Group.^[3] Tait et al. assigned it to the newly defined Artesia Group in 1962.^[2]

See also

• Earth sciences portal
• Paleontology portal

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