The Tansill Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

in southeastern

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and west

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, United States.DeFord ''et al.'' 1928 It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

dating back to the late

Guadalupian The Guadalupian is the second and middle Series (stratigraphy), series/Epoch (geology), epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico an ...

Age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

of the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

.Tait ''et al.'' 1962

Description

The formation consists of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

, and

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...

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 The Delaware Basin is a geologic depositional and structural basin in West Texas and southern New Mexico, famous for holding large oil fields and for a fossilized reef exposed at the surface. Guadalupe Mountains National Park and Carlsbad Cav ...

, and grades into anhydrite in the north and east. It forms the top of the Capitan reef but dips steeply into the subsurface.DeFord and Riggs 1941 It has a total thickness of .Newell ''et al.'' 1953 It overlies the Yates Formation.King 1948 The formation is part of the Artesia Group, which is interpreted as a shelf rock sequence.

History of investigation

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

Footnotes

References

* * * * Newell, N.D., Rigby, J.K., Fischer, A.G., Whiteman, A.J., HIckox, J.E., and Bradley, J.S., 1953, ''The Permian reef complex of the Guadalupe Mountains region, Texas and New Mexico; a study in paleoecology'': San Francisco, W.H. Freeman and Company * {{cite journal , last1=Tait , first1=D.B. , last2=Ahien , first2=J.L. , last3=Gordon , first3=A. , last4=Scott , first4=G.L. , last5=Motts , first5=W.S. , last6=Spitler , first6=M.E. , title=Artesia Group of New Mexico and West Texas , journal=AAPG Bulletin , date=1962 , volume=46 , issue=4 , pages=504–517 , doi=10.1306/BC74383B-16BE-11D7-8645000102C1865D Permian formations of New Mexico Permian formations of Texas Limestone formations of the United States Siltstone formations of the United States

Description

History of investigation

See also

Footnotes

References