The Bursum 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 ...

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 ...

.Bursum Formation
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org 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 in ...

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 (Son of Dave album), ''01'' (Son of Dave album), 2000 * 01 (Urban ...

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 ...

Description

The Bursum Formation is primarily

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

but with substantial

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 ...

, particularly in its lower beds, with a thickness in excess of . It rests disconformably on the

Atrasado Formation The Atrasado Formation is a geologic formation in New Mexico. Its fossil assemblage dates the formation to the Kasimovian age of the Pennsylvanian. It was formerly known locally as the Wild Cow Formation or the Guadelupe Box Formation. Descript ...

and grades into the overlying

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 ...

. It represents the transitional zone between the marine

Madera Group The Madera Group is a group of geologic formations in northern New Mexico. Its fossil assemblage dates the formation to the middle to late Pennsylvanian period. Description The group consists primarily of marine limestones, and it is exposed in ...

and the continental Abo Formation. The Red Tanks Member is composed mostly of variegated

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

, mudstone, and

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.Blatt ''et al.'' 1980, p ...

of nonmarine origin, with some beds of marine limestone and shale forming six transgressive depositional sequences. Its type section is at Carrizo Arroyo (). It is also present at Abo Pass. The Bursum Formation has a more consistently marine character further south. The fact that the transgressive sequences are fewer in number than the

cyclothems In geology, cyclothems are alternating stratigraphy, stratigraphic sequences of Marine (ocean), marine and non-marine sediments, sometimes interbedded with coal seams. Historically, the term was defined by the European coal geologists who worked ...

of the Pennsylvanian-

Permian The Permian ( ) is a geologic period and 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 of the Paleoz ...

boundary in the North American mid-continent shows that

tectonics Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...

had more influence on the development of this formation than

glacial cycle An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

Fossil content

Fossils found in the formation include the

fusulinid 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 di ...

'' Triticites'' from which its early Permian age is determined. The formation also preserves fossils of the

foram Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an ...

s '' Bradyina lucida'' and '' Eostaffella''. There are two '' Lagerstätten'' in the Red Tanks Member at Carrizo Arroyo that are of early

Asselian In the geologic timescale, the Asselian is the earliest geochronologic age or lowermost chronostratigraphic stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Asselian lasted between and million years ago (Ma). It ...

age, while the recent definition of the base of the Permian as the first appearance of the

conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...

'' Streptognathus isolatus'' pushes the earliest part of the formation, and the associated North American

Wolfcampian The Cisuralian is the first Series (stratigraphy), series/Epoch (geology), epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian (geology), Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the w ...

Stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

back into the latest Pennsylvanian. The Red Tanks Member also contains biogenic carbonate nodules (

oncolite Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by cyanobacterial growth. Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. T ...

s) at Cibola Spring () in a distinctive, widespread limestone horizon. These are unusual in being composed mostly of forams rather than

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

and are interpreted as having formed in a shelf environment below the

euphotic The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological proc ...

zone or normal

wave base The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. At water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion ab ...

but above the storm wave base.

History of investigation

The Bursum Formation was first defined by R.H. Wilpolt and coinvestigators in 1946 for exposures near the Bursum triangulation point in the northern

Jornada del Muerto The name Jornada del Muerto translates from Spanish as "Single Day's Journey of the Dead Man" or even "Route of the Dead Man, though the modern literal translation is closer to "The Working Day of the Dead". It was the name given by the Spanish ...

and in the Los Pinos Mountains. They assigned the formation to the (now-defunct) Magdalena Group. M.L. Thompson later redefined the formation as including all Permian beds older than the Abo Formation, characterizing these as transitional beds between the marine beds of the Madera Group and the Abo Formation. D.A. Myers assigned the formation to the Madera Group in 1972. In his revision of Pennsylvanian stratigraphy in New Mexico in 2001, Barry S. Kues retained this assignment, except in the Joyita Hills. He also correlated the formation with the

Laborcita Formation The Laborcita Formation is a geologic formation in the Sacramento Mountains of New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.Otté 1959 Description The formation is composed mostly of marine beds consisti ...

and Red Tanks Formation (which he regarded as a separate formation).

References

Bibliography

* * * * * * * * {{cite journal , last1=Wilpolt , first1=R.H. , last2=MacAlpin , first2=A.J. , last3=Bates , first3=R.L. , last4=Vorbe , first4=George , year=1946 , title=Geologic map and stratigraphic sections of Paleozoic rocks of Joyita Hills, Los Pinos Mountains, and northern Chupadera Mesa, Valencia, Torrance, and Socorro Counties, New Mexico , journal=U.S. Geological Survey Oil and Gas Investigations Preliminary Map , volume=OM-61 , url=https://ngmdb.usgs.gov/Prodesc/proddesc_5422.htm , access-date=24 January 2021 Permian formations of New Mexico Permian System of North America Asselian Limestone formations of the United States Mudstone formations Lacustrine deposits Permian paleotropical deposits Paleontology in New Mexico

Description

Fossil content

History of investigation

See also

References

Bibliography