The Baruungoyot Formation (also known as Barun Goyot) is a

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 ...

dating to the Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Period. It is located within and is widely represented in the

Gobi Desert The Gobi Desert (, , ; ) is a large, cold desert and grassland region in North China and southern Mongolia. It is the sixth-largest desert in the world. The name of the desert comes from the Mongolian word ''gobi'', used to refer to all of th ...

Basin, in the

Ömnögovi Province Ömnögovi ( ''Ömnögovǐ'', ''South Gobi'') is an aimag (province) of Mongolia, located in the south of the country, in the Gobi Desert. Ömnögovi is Mongolia's largest aimag. The capital is Dalanzadgad. The province is rich in mineral dep ...

of Mongolia.

Description

It was previously known as the Lower Nemegt Beds occurring beneath the

Nemegt Formation The Nemegt Formation (also known as Nemegtskaya Svita) is a geological formation in the Gobi Desert of Mongolia, dating to the Late Cretaceous. The formation consists of river channel sediments and contains fossils of fish, turtles, crocodilians ...

and above the

Djadokhta Formation The Djadochta formation (sometimes transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation in Central Asia, Gobi Desert, dating from the Late Cretaceous period, about 75 million ...

. It has been suggested that the Djadokhta and Baruungoyot Formations are lower and upper parts, respectively, of the same lithological unit and the boundary between the two does not exist. The

stratotype In geology, a stratotype or type section is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the ...

of the Baruungoyot Formation is the Khulsan locality, east of Nemegt. At Nemegt, only the uppermost barungoyotian beds are visible. The ''Red Beds of Khermeen Tsav'' are also considered part of the Baruungoyot Formation. It is approximately in thickness,Gradzinski, R.; & Jerzykiewicz, T. (1974). Sedimentation of the Barun Goyot formation. Palaeontologica Polonica, 30, 111-146. and was laid down roughly 72-71 million years ago. Given the new date for the start of the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

(72.1 MYA) a basal Maastrichtian age seems probable. The Baruungoyot Formation preserves an environment of

sand dunes A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

, created from wind-eroded rocks ( aeolian dunes).

Paleobiota of the Baruungoyot Formation

Lizards

Mammals

Dinosaurs

Ornithiscians

= Ankylosaurs

= Ceratopsians

= Pachycephalosaurs

Sauropods

Theropods

= Alvarezsaurs

= Birds

= Dromaeosaurids

=Troodontids

= Oviraptorosaurs

Gallery

File:10 2 Proti Kermen Tsav (34).JPG File:10 2 Proti Kermen Tsav (31).JPG File:Khermen Tsav - Shambala gate - panoramio.jpg File:Hermen Tsav - panoramio.jpg File:Nemegt and Baruungoyot Formations.png

References

{{Reflist, refs= {{cite book, last=Benton, first=M.J., author-link=Michael J. Benton, chapter=Mongolian Place Names and Stratigraphic Terms, pages=xxii-xxviii, editor-last=Benton, editor-first=M.J., editor2-last=Shishkin, editor2-first=M.A., editor3-last=Unwin, editor3-first=D.M., editor4-last=Kurochkin, editor4-first=E.N., title=The Age of Dinosaurs in Russia and Mongolia, publisher=Cambridge University Press, isbn=0-521-55476-4 Geologic formations of Mongolia Upper Cretaceous Series of Asia Sandstone formations Geologic formations with imbedded sand dunes Aeolian deposits