The Ulaanoosh Formation, formerly Baruunbayan Formation, is a
geologic formation in the
Ömnögovi Province of southern
Mongolia. The formation dates to the
Albian to
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
stages of the
Cretaceous. The Ulaanoosh Formation has provided fossils of
dinosaurs,
turtles and
dinosaur eggs assigned to ''
Parafaveoloolithus sp.''. In
2020
2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of events, COVID- ...
, the
neoceratopsian ''
Beg tse
''Beg'' (after the Himalayan war deity Beg-tse) is a genus of neoceratopsian dinosaur from the early Cretaceous period of Mongolia. The genus contains a single species, ''Beg tse'', known from a partial skull and very fragmentary postcrania. '' ...
'' was described from the
alluvial sandstones,
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. ...
s and
conglomerates of the formation.
Description
The Ulaanoosh Formation was formerly considered to be the Baruunbayan Formation (or Baruunbayan Svita in Russian or Mongolian),
[Baruunbayan 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 first documented by the Soviet-Mongolian Paleontological Expeditions between 1946 and 1949. These beds are now considered to be part of the Ulaanoosh Formation. Shuvalov (1982) recognized the red beds at Baruunbayan based on exposures near mountains adjacent to the towns of
Baruunbayan and
Zuunbayan. Later, the Baruunbayan Svita was more thoroughly studied during a large geological mapping project carried out in the same area by a variety of studies. Due to insufficient representation (only partial sections are exposed at these localities), Badamgarav et al. in 1995 proposed that the Ulaanoosh Formation represents a complete section of red beds in the Baruunbayan area based on drill logs. The Ulaanoosh Formation is distributed in the areas of Ulaanoosh, Alguu Ulaan Tsav, Baruunbayan, and Zuunbayan. The age of the Ulaanoosh Formation ranges from late Early to early Late Cretaceous (
Albian-
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
) based on vertebrate and invertebrate fossils such as dinosaurs, dinosaur eggs, molluscs, ostracods, and turtles.
[Yu et al., 2020, p.2]
The Ulaanoosh Formation is composed of two members: a lower and an upper. The lower member (Aptian to Albian) comprises white-colored
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. ...
s, fine-grained
conglomerates, bright gray colored, carbonate-rich
sandstones, yellowish fine-grained sandstones with carbonate concretions and gray colored conglomerates preserving invertebrate fossils. The upper member is largely composed of reddish colored, fine to medium grained
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. ...
s, fine-medium grained conglomerates, and a
breccia layer in the base. The upper member of the formation preserved fragmentary sauropods and dinosaur eggs ''
Faveoloolithus
''Faveoolithus'' is an oogenus of dinosaur egg. The oogenus contains two oospecies, ''F. ningxiaensis'' and ''F. zhangi''.[Early
Early may refer to:
History
* The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.:
** Early Christianity
** Early modern Europe
Places in the United States
* Early, Iowa
* Early, Texas
* Early ...]
and
Late Cretaceous (~100.5 Ma).
[
]
Fossil content
The following fossils have been reported from the formation:[
]
See also
* List of dinosaur-bearing rock formations
* Alagteeg Formation
The Alagteeg Formation is a geological formation in Mongolia whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel et al., 2004, pp.593-600 It predominantly cons ...
* Khuren Dukh Formation
The Khuren Dukh Formation, also known as the Hühteeg Svita, ( mn, Хөхтээг формаци, ) is a geological formation in Mongolia whose strata date back to the middle to late Albian.Nichols et al., 2006 Dinosaur remains are among the foss ...
References
Bibliography
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{{CC-notice, cc=by4, url=https://www.nature.com/articles/s42003-020-01222-7, author(s)=Congyu Yu, Albert Prieto-Marquez, Tsogtbaatar Chinzorig, Zorigt Badamkhatan & Mark Norell
Geologic formations of Mongolia
Cretaceous System of Asia
Cretaceous Mongolia
Albian Stage
Cenomanian Stage
Conglomerate formations
Mudstone formations
Sandstone formations
Alluvial deposits
Ooliferous formations
Fossiliferous stratigraphic units of Asia
Paleontology in Mongolia
Formations