Öösh Formation

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title: "Öösh Formation" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["geologic-formations-of-mongolia", "lower-cretaceous-series-of-asia", "cretaceous-mongolia", "berriasian-stage", "valanginian-stage", "hauterivian-stage", "barremian-stage", "sandstone-formations", "conglomerate-formations", "siltstone-formations", "mudstone-formations", "alluvial-deposits", "fossiliferous-stratigraphic-units-of-asia", "paleontology-in-mongolia", "övörkhangai-province"] description: "Geological formation in Övörkhangai, Mongolia" topic_path: "philosophy" source: "https://en.wikipedia.org/wiki/Öösh_Formation" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Geological formation in Övörkhangai, Mongolia ::

::data[format=table title="Infobox rockunit"]

Field	Value
name	Öösh Formation
type	Geological formation
age	Berriasian-Barremian
~
period	Early Cretaceous
prilithology	Sandstone, claystone, shale
otherlithology	Siltstone
region	Ovorkhangai
country	Mongolia
coordinates
paleocoordinates
subunits	Cannonball beds
underlies	Basalt
overlies	Basement
thickness	600 m
map	{{Location map+
relief	1
width	250
float	center
lat_deg	44.2
lon_deg	102.7
mark	Green pog.svg
marksize	10
::

| name = Öösh Formation | image = | caption = | type = Geological formation | age = Berriasian-Barremian ~ | period = Early Cretaceous | prilithology = Sandstone, claystone, shale | otherlithology = Siltstone | namedfor = | namedby = | region = Ovorkhangai | country = Mongolia | coordinates = | paleocoordinates = | unitof = | subunits = Cannonball beds | underlies = Basalt | overlies = Basement | thickness = 600 m | extent = | area = | map = {{Location map+ | Mongolia | relief = 1 | width = 250 | float = center | places = | lat_deg = 44.2 | lon_deg = 102.7 | mark = Green pog.svg | marksize = 10 | map_caption = The Öösh Formation, also known as the Tevsh Formation is a geological formation of Lower Cretaceous strata in Övörkhangai Province, Mongolia. Dinosaur remains are among the fossils that have been recovered from the formation. It overlies folded and metamorphosed basement strata of the Gobi region, and is capped by basalt. The succession is around 600 metres thick and consists of red claystones and sandstones, along with black thinly laminated shales. The claystones and sandstones were deposited as part of an alluvial fan system, while the shales were deposited in lakes present in the foot of the fan. Many of the fossils come from the "Cannonball beds", which comprise the lowest 60 metres of the unit and consist of green siltstone.

Vertebrate paleofauna

Dinosaurs

::data[format=table]

Dinosaurs of the Öösh Formation	Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Asiatosaurus	A. mongoliensis			Teeth	Indeterminate sauropod
Halszkaraptorinae indet.				ISMD-VP09, preserving a maxillary fragment, two teeth, and partial appendicular elements	Halszkaraptorine
Prodeinodon	P. mongoliensis			Several teeth, fragmentary tibia, fragmentary fibula	Indeterminate theropod
Protiguanodon	P. mongoliensis				Reclassified as a species of Psittacosaurus, Psittacosaurus protiguanodonensis
Psittacosaurus	P. mongoliensis					[[File:Psittacosaurus stomach stones.jpg	thumb
P. protiguanodonensis				Junior synonym of P. mongoliensis
last=Turner	first=A.S.	author2=Hwang, S.H.	author3= Norell, M.A.	year=2007	title=A small derived theropod from Öösh, Early Cretaceous, Baykhangor Mongolia	journal=American Museum Novitates	issue=3557
::

Mammals

::data[format=table]

Mammals of the Öösh Formation	Genus	Species	Location	Stratigraphic position	Material	Notes	Images
author=Kielan-Jaworowska, Z., Dashzeveg, D.	year=1998	title=Early Cretaceous amphilestid ("triconodont") mammals from Mongolia	journal= Acta Palaeontologica Polonica	volume=43	issue=3	pages=413–438	url=http://app.pan.pl/archive/published/app43/app43-413.pdf}}
::

Pterosaurs

::data[format=table]

Pterosaurs of the Öösh Formation	Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Indeterminate tapejaroid				"Single cervical vertebra (IGM 100/1321)"
::

Squamates

::data[format=table]

Squamates of the Öösh Formation	Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Norellius	N. nyctisaurops			"Nearly complete skull with mandibles and partial hyoid"	Gekkonomorph
::

References

References

1. Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. {{ISBN. 0-520-24209-2.
2. (2011). "A diminutive deinonychosaur (Dinosauria: Theropoda) from the Early Cretaceous of Öösh (Övörkhangai, Mongolia)". Alcheringa: An Australasian Journal of Palaeontology.
3. (2019-07-10). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ.
4. Turner, A.S.. (2007). "A small derived theropod from Öösh, Early Cretaceous, Baykhangor Mongolia". American Museum Novitates.
5. Kielan-Jaworowska, Z., Dashzeveg, D.. (1998). "Early Cretaceous amphilestid ("triconodont") mammals from Mongolia". Acta Palaeontologica Polonica.
6. Andres, B. and Norell, M.A. 2005. [http://digitallibrary.amnh.org/bitstream/handle/2246/2782/v2/dspace/ingest/pdfSource/nov/N3472.pdf?sequence=1 The first record of a pterosaur from the Early Cretaceous strata of Öösh (Övörkhangai; Mongolia).] American Museum Novitates 3472: 1–6. [http://www.bioone.org/doi/abs/10.1206/0003-0082(2005)472%3C0001:TFROAP%3E2.0.CO%3B2]
7. "Tapejaroidea indet.". Fossilworks.
8. (2015-08-28). "Naming and rediagnosing the Cretaceous gekkonomorph (Reptilia, Squamata) from Öösh (Övörkhangai, Mongolia)". Journal of Vertebrate Paleontology.

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