The Hueco 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 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 ...

and southern

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 ...

.Richardson 1904Richardson 1908Richardson 1914 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

early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

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 ...

.Nelson 1940Bachman and Hayes 1958

Description

The formation is composed most of massive gray

fossiliferous limestone Fossiliferous limestone is a type of limestone that contains noticeable quantities of fossils or trace fossil, fossil traces. If a particular type of fossil dominates, a more specialized term can be used as in "Ames Limestone, Crinoidal", "Coral ...

with some

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

and

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, with a thickness in excess of . It overlies the Panther Seep FormationKelley and Matheny 1983 with a slight disconformity, and its base is typically a thick biostromal limestone bed.Kues and Giles 2004 The formation unconformably underlies the Wilkie Ranch Formation.Cys 1976 It intertongues with the

Abo Formation The Abo Formation is a geologic formation in New Mexico. It contains fossils characteristic of the Cisuralian epoch of the Permian period. Description The Abo Formation consists of fluvial redbed mudstones and sandstones, including river channel ...

in the southern

San Andres Mountains The San Andres Mountains are a mountain range in the southwestern U.S. state of New Mexico, in the counties of Socorro, Sierra, and Doña Ana. The range extends about north to south, but are only about wide at their widest. The highest peak ...

. In the

Robledo Mountains The Robledo Mountains are a mountain range in Doña Ana County, New Mexico, just northwest of Las Cruces. They are an uplifted block of Paleozoic rocks on the west side of the Rio Grande Rift. The range was named for Pedro Robledo, who died o ...

, the Hueco is promoted to

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

rank and divided into (in ascending stratigraphic order) the Shalem Colony, Community Pit, Robledo Mountains, and Apache Dam Formations.Lucas ''et al.'' 1998 In the Hueco Mountains, the uppermost formation is the Alacran Mountain Formation.Williams 1963 The Hueco Formation is contemporary with the

and represents continued marine sediment deposition south of the prograding Abo

delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

History of investigation

The formation was first defined by G.B. Richardson in 1904, but mistakenly thought to be

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timesc ...

in age. Nelson dated the formation as earliest Permian in the Franklin Mountains in 1940. Spencer G. Lucas ''et al.'' promoted the formation to group rank in 1998.

Footnotes

Bibliography

* * * * * * * * * * {{cite journal , last1=Williams , first1=T.E. , year=1963 , title=Fusulinidae of the Hueco Group (Lower Permian), Hueco Mountains, Texas , journal=Peabody Museum of Natural History Bulletin , volume=18 Limestone formations of the United States Permian formations of New Mexico Permian geology of Texas Shale formations of the United States Sandstone formations of the United States

Description

History of investigation

See also

Footnotes

Bibliography