The Tuerto 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 ...

exposed around the

Ortiz Mountains The Ortiz Mountains are a mountain range in northern New Mexico, United States, in Santa Fe County, northeast of the Sandia Mountains and due north of the San Pedro Mountains. The Ortiz include Placer Peak, the highest peak in the range at 8,858 ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

. It is estimated to be of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

age, and forms the gravel cap of the Ortiz surface, one of the first pediment surfaces recognized by

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

Description

The Tuerto Formation consists primarily of

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

with minor

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

. The clasts (rock fragments) making up the conglomerate consist largely of hornfels and Ortiz porphyry eroded off the

and Cerrillos Hills and deposited as a thin alluvial fan in the Hagan basin. Beds containing

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

clasts eroded off the east slopes of the

Sandia Mountains The Sandia Mountains (Southern Tiwa: ''Posu gai hoo-oo'', Keres: ''Tsepe,'' Navajo: ''Dził Nááyisí''; Tewa: ''O:ku:p’į'', Northern Tiwa: ''Kep’íanenemą''; Towa: ''Kiutawe'', Zuni: ''Chibiya Yalanne'') are a mountain range located in ...

are sometimes also included in the formation. The formation is informally divided into a lower well- cemented cliff-forming

member Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

and an upper poorly cemented member. The formation lies with angular unconformity on the Blackshare Formation. It is distinguished from the coeval Ancha Formation in containing mostly volcanic clasts, while the Ancha Formation is rich in

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

clasts.

The unit underlies the Ortiz surface, one of the first pediment surfaces recognized, by I.H. Ogilvie in 1905.

History

The unit was first named the Tuerto Gravel by C.E. Stearns in 1953 for exposures southwest of

Santa Fe, New Mexico Santa Fe ( ; , Spanish for 'Holy Faith'; tew, Oghá P'o'oge, Tewa for 'white shell water place'; tiw, Hulp'ó'ona, label=Tiwa language, Northern Tiwa; nv, Yootó, Navajo for 'bead + water place') is the capital of the U.S. state of New Mexico. ...

. Daniel Koning, Sean Connell, Frank Pazzaglia, and William McIntosh described the unit as the Tuerto formation in 2020, and Connell first argued for formalizing it at formation rank in a footnote to a 2002 paper. It was so treated in a draft geologic map of the Hagan area in 2002.

References

Bibliography

* * * * * {{cite journal , last1=Stearns , first1=Charles E. , title=Tertiary geology of the Galisteo-Tonque area, New Mexico , journal=Geological Society of America Bulletin , date=1953 , volume=64 , issue=4 , pages=459 , doi=10.1130/0016-7606(1953)64 59:TGOTGA.0.CO;2, bibcode=1953GSAB...64..459S Neogene formations of New Mexico