The Goat Seep 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 ...

found in western

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

and southeastern

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, Ke ...

. It is a

fossil 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 ...

ized

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...

dating to the

Guadalupian The Guadalupian is the second and middle series/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 and Texas, and dates between 272.95 ± ...

Age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or 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 251.9 Mya. It is the last ...

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. The formation underlies Bartlett Peak () and nearby areas in

Guadalupe Mountains National Park Guadalupe Mountains National Park is an American national park in the Guadalupe Mountains, east of El Paso, Texas. The mountain range includes Guadalupe Peak, the highest point in Texas at , and El Capitan used as a landmark by travelers on the ...

Description

The Goat Seep Formation consists of up to of massive to thickly bedded light grey to white

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

. The lower part of the formation contains some

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 ...

beds. It grades below into the

Cherry Canyon Formation The Cherry Canyon Formation is a geologic formation found in the Delaware Basin of southeastern New Mexico and western Texas. It contains fossils characteristic of the Guadalupian Age of the Permian Period.Kues and Giles 2004, p.100 Description ...

and is overlain by the

Capitan Formation The Capitan Formation is a geologic formation found in western Texas and southeastern New Mexico. It is a fossilized reef dating to the Guadalupian Age of the Permian period. The formation underlies El Capitan in Guadalupe Mountains National Park ...

, a younger Permian reef. The Capitan Formation and Goat Seep Formation are quite similar, but are separated by an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

marked by ledges of dark limestone. The formation represents a fossil reef, and grades laterally into the shelf limestones of the Grayburg and Queen Formations. It is regarded as a precursor to the Capitan reef. The reef was built mostly by red ('' Solenopora'') and green ( Dasycladaceae) algae and cyanobacteria (''

Girvanella ''Girvanella'' is a fossil thought to represent the calcified sheath of a filamentous cyanobacterium known from the Burgess Shale and other Cambrian fossil deposits. ''Girvanella'' was originally described as a foraminifera. It was later assign ...

'') with calcareous sponges,

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...

, and

hydrocoral Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, heavily discussed, and spectacular group. It has also been called Gymnobla ...

s also playing a role.

Fossils

Portions of the formation are highly fossiliferous, and these include beds very rich in

fusulinids The Fusulinida is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was dif ...

. However,

dolomitization Dolomitization is a geological process by which the carbonate mineral dolomite is formed when magnesium ions replace calcium ions in another carbonate mineral, calcite. It is common for this mineral alteration into dolomite to take place due to e ...

(conversion of the original

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 ...

to dolomite) has resulted in very poor preservation of most of these fossils. The fusulinid ''

Parafusulina ''Parafusulina'' is a genus of foraminifera included in the fusulinacean family Schwagerinidae that were extant during the Permian. The shell, or test, of ''Parafusulina'' is elongate, up to 65 mm in length, fusiform to subcylindrical in sh ...

rothi'' has been identified in a few locations. Other tentative identifications are of the

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

'' Guadalupia zitteliana'', several genera of

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, w ...

s, some poorly preserved

gastropods The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...

, and a species of

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

, '' Anisopyge perannulata''.

History of investigation

The beds were first described by K.H. Crandall and assigned to the Chupadera Formation, a unit recognized in central New Mexico but since abandoned. W.B. Land assigned the same beds to the Dog Canyon Limestone, but P.B. King found this name too similar to that of a unit in the oil fields of Oklahoma, and he renamed the unit as the Goat Seep Limestone. N.D. Newell and coinvestigators renamed the formation as the Goat Seep Dolomite, due to its extensive dolomitization, and reassigned the shelf facies originally assigned to the formation to the Queen Formation.

References

{{Reflist Permian geology of Texas Permian formations of New Mexico

Description

Fossils

History of investigation

See also

References