The Barzalosa Formation (, Pgb, Pgba) is a

fossiliferous 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 i ...

geological 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 expo ...

of the

Upper Magdalena Valley Upper may refer to: * Shoe upper or ''vamp'', the part of a shoe on the top of the foot * Stimulant, drugs which induce temporary improvements in either mental or physical function or both * ''Upper'', the original film title for the 2013 found fo ...

and the bounding foothills of the

Central Ranges Central Ranges (code CER) is an Australian bioregion, with an area of 101,640.44 square kilometres (39,244 sq mi) spreading across two states and one territory: South Australia, Western Australia, and the Northern Territory.Eastern Ranges The Eastern Ranges is an Australian rules football team that currently competes in the Talent League, the Victorian statewide under-18s competition. History Inaugural playing squad (1992) Honours *Premiers (2): 2002, 2013 *Runners-up (6): 199 ...

of the

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The formation consists of conglomerates,

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 ...

s 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. Although its permeabil ...

s. The Barzalosa Formation probably dates to the

Late Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

to Early Neogene period;

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

epochs, and has an approximate thickness of . Fossils of '' Balanerodus logimus'', '' Lophiodolodus chaparralensis'', '' Xenastrapotherium chaparralensis'', '' Protheosodon sp.'' and '' Proadinotherium sp.'' have been uncovered from the formation in

Chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

, Tolima.

Etymology

The formation was defined by Scheibe in 1934 and named after Barzalosa, a ''vereda'' of Girardot, Cundinamarca. Cáceres and

Etayo Etayo () is a town and municipality located in the province and autonomous community of Navarre, northern Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. F ...

elevated the "Pisos de Barzalosa" to a formation in 1969.Acosta et al., 2002, p.49

Description

Lithologies

The Barzalosa Formation consists of conglomerates,

s and

s.Acosta et al., 2002, p.50 In parts, the formation contains

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 ...

beds and

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...

.Acosta & Ulloa, 2001, p.56

Stratigraphy and depositional environment

The approximately thick Barzalosa Formation overlies the Olini Group and the Seca Formation in the west and is overlain by the

Honda Group commonly known as just Honda, is a Japanese multinational conglomerate automotive manufacturer headquartered in Minato, Tokyo, Japan. Founded in October 1946 by Soichiro Honda, Honda has been the world's largest motorcycle manufacturer sin ...

. In the east towards

Fusagasugá Fusagasugá (; ) or Fusa is a city and municipality in the department of Cundinamarca, in central Colombia. It is located in the warm valley between the rivers Cuja and Panches, a central region of the Andes Mountains in South America. The mun ...

, the formation overlies the La Tabla Formation and is overlain by the

Carmen de Apicalá Conglomerate ''Carmen'' () is an opera in four acts by the French composer Georges Bizet. The libretto was written by Henri Meilhac and Ludovic Halévy, based on the Carmen (novella), novella of the same title by Prosper Mérimée. The opera was first perfo ...

.Acosta & Ulloa, 2001, p.52 As the formation does not contain

foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

, the age is difficult to establish, but has been estimated to be

, or

Middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

to Oligocene.Acosta & Ulloa, 2001, p.57 The depositional environment has been interpreted as

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

s and

braided river A braided river (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. ...

s.Acosta et al., 2002, p.51

Fossil content

Outcrops

The Barzalosa Formation is apart from its type locality found in

Tocaima Tocaima () refers to both a city and a municipality in Cundinamarca, Colombia. City The city of Tocaima was founded on March 20, 1544 as San Dionisio de los Caballeros de Tocaima by the Spanish explorer Hernán Venegas Carrillo. This city is mos ...

and to the east of

Agua de Dios Agua de Dios (, literally in ) is a municipality and town of Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The ...

, and on the western side of the

Magdalena River The Magdalena River (, ; less commonly ) is the main river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, ...

around

, Tolima.

Regional correlations

Notes

References

Bibliography

* *

Maps

* * {{Paleontology in Colombia, state=collapsed Geologic formations of Colombia Paleogene Colombia Neogene Colombia Oligocene Series of South America Miocene Series of South America Conglomerate formations Sandstone formations Siltstone formations Alluvial deposits Fluvial deposits Fossiliferous stratigraphic units of South America Paleontology in Colombia Formations Formations

Etymology

Description

Lithologies

Stratigraphy and depositional environment

Fossil content

Outcrops

Regional correlations

See also

Notes

References

Bibliography

Maps