Bakhar Formation

Last updated
Bakhar Formation
Stratigraphic range: Aalenian-Bathonian
~174–166  Ma
Type Geological formation
Lithology
Primary Claystone
Other Coal
Location
Coordinates 44°54′N100°54′E / 44.9°N 100.9°E / 44.9; 100.9
Approximate paleocoordinates 48°06′N105°12′E / 48.1°N 105.2°E / 48.1; 105.2
CountryFlag of Mongolia.svg  Mongolia
Extent North Molasse Basin
Relief map of Mongolia.png
Blue pog.svg
Blue pog.svg
Bakhar Formation (Mongolia)

The Bakhar Formation (Russian: Bakhar Svita) is a geological formation in Mongolia whose strata date back to the Aalenian to Bathonian stages of the Middle Jurassic, comprising claystones deposited in a lacustrine environment. [1]

Contents

Fossil content

Insects; Platyperla propera , [2] Ano da , A. net, A. nym, Blattula anuniversala , B. bacharensis, B. flamma, B. mikro, B. mini, B. universala, B. velika, B. vulgara, Caloblattina vremeni , Dostavba pre , Hra disko , H. bavi, H. nie, Nuurcala cela , Okras sarko , Perlucipecta cosmopolitana , Polliciblattula analis , P. tatosanerata, P. vana, Praeblattella jurassica , Raphidiomima chimnata , R. krajka, Rhipidoblattina bakharensis , R. konserva, R. sisnerahkab, Solemnia togokhudukhensis , Truhla vekov , [3] fish (Palaeonisciformes) and pterosaur remains of the family Anurognathidae have been recovered from the formation. [4] [5] The formation has also provided many fossil flora in its coal layers, known as the Tsagan-Ovoo Flora containing 32 megafossil plant taxa belonging to horsetails, ferns, cycadaleans, ginkgoaleans, leptostrobaleans, conifers and gymnosperms. Three new species were named; Ginkgo badamgaravii , Pseudotorellia gobiense and P. mongolica . [6]

See also

Related Research Articles

<span class="mw-page-title-main">Kyzylkum Desert</span> Desert in Central Asia between the Amu Darya and Syr Darya

The Kyzylkum Desert is the 15th largest desert in the world. Its name means Red Sand in Turkic languages. It is located in Central Asia, in the land between the confluent rivers Amu Darya and Syr Darya, a region historically known as Transoxania. Today it is divided between Kazakhstan, Turkmenistan and Uzbekistan. It covers about 298,000 km2 (115,000 sq mi).

<span class="mw-page-title-main">Anurognathidae</span> Family of pterosaurs from the Jurassic and Cretaceous periods

Anurognathidae is a family of small, short-tailed pterosaurs that lived in Europe, Asia, and possibly North America during the Jurassic and Cretaceous periods. Five genera are known: Anurognathus, from the Late Jurassic of Germany; Jeholopterus, from the Middle to Late Jurassic of China; Dendrorhynchoides, from the Middle Jurassic of China; Batrachognathus, from the Late Jurassic of Kazakhstan; and Vesperopterylus, from the Early Cretaceous of China. Bennett (2007) suggested that the holotype of Mesadactylus, BYU 2024, a synsacrum, belonged to an anurognathid, though this affinity has been questioned by other authors. Mesadactylus is from the Late Jurassic Morrison Formation of the United States. Indeterminate anurognathid remains have also been reported from the Middle Jurassic Bakhar Svita of Mongolia and the Early Cretaceous of North Korea.

<i>Noripterus</i> Genus of dsungaripterid pterosaur from the Early Cretaceous

Noripterus is a genus of dsungaripterid pterodactyloid pterosaur from Lower Cretaceous-age Lianmuqin Formation in the Junggar Basin of Xinjiang, China. It was first named by Yang Zhongjian in 1973. Additional fossil remains have been recovered from Tsagaantsav Svita, Mongolia.

Dermodactylus was a genus of pterodactyloid pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Wyoming, United States. It is based on a single partial bone, from the hand.

<i>Pterorhynchus</i> Genus of darwinopteran pterosaur from the Middle Jurassic

Pterorhynchus is an extinct genus of pterosaur from the mid-Jurassic aged Daohugou Formation of Inner Mongolia, China.

<i>Notobatrachus</i> Extinct genus of amphibians

Notobatrachus is an extinct genus of frog from the Lower Jurassic (Toarcian) Cañadon Asfalto Formation, Cañadón Asfalto Basin and Middle Jurassic La Matilde Formation, Deseado Massif of Patagonia, Argentina. N. degiustoi is the most completely known Jurassic frog and has been recorded in many outcrops of the La Matilde Formation of the Deseado Massif in southern Patagonia.

The Kota Formation is a geological formation in India. The age of the Kota Formation is uncertain; it is commonly considered to date to the Early Jurassic, but some studies have suggested it may extend into the Middle Jurassic or even later. It conformably overlies the Lower Jurassic Upper Dharmaram Formation and is unconformably overlain by the Lower Cretaceous Gangapur Formation. It is split into a Lower Member and Upper Member. The lower member is approximately 100 m thick while the upper member is 490 m thick. Both subunits primarily consist of mudstone and sandstone, but near the base of the upper unit there is a 20-30 metre thick succession of limestone deposited in a freshwater setting.

The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch. Although, the latest studies had proven that the local Vulcanism, related to the aperture of the Atlantic Ocean and the several Rift Events, that continue until the Bajocian, while the unit itself was likely deposited between the earliest Pliensbachian, as proven by zircon with the fossil taxa deposited on the rocks above, likely of Late Pliensbachian-Lower Toarcian age, and the upper section of Late Toarcian-Late Aalenian age. Due to successions of Aalenian depositional sistems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation. Deposits of Late Triassic Age referred to this unit have been reclassified in a new formation, El Alamar Formation. In North America, La Boca Formation was found to be a regional equivalent of the Eagle Mills redbeds of southern United States, the Todos Santos Formation of southern Mexico and the Barracas Group of the Sonora desert region.

<span class="mw-page-title-main">Tiaojishan Formation</span>

The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period. It is known for its exceptionally preserved fossils, including those of plants, insects and vertebrates. It is made up mainly of pyroclastic rock interspersed with basic volcanic and sedimentary rocks. Previously, the Tiaojishan Formation was grouped together with the underlying Haifanggou Formation as a single "Lanqi Formation." The Tiaojishan Formation forms a key part of the Yanliao Biota assemblage, alongside the Haifanggou Formation.

The Tsagaantsav Formation, Tsagantsab Formation or Tsagan-Tsab Formation is an Early Cretaceous geologic formation in Mongolia. Indeterminate sauropod and psittacosaurid remains have been recovered from the formation. Remains of the pterosaur Noripterus, which were originally given their own genus, "Phobetor" have also been recovered from the formation.

The Andaikhudag Formation, in older literature referred to as Unduruh Formation or Ondorukhaa Formation, is an Early Cretaceous geologic formation in Mongolia. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

The Ialovachsk or Yalovach Formation is a geologic formation in Kyrgyzstan, Tajikistan and Uzbekistan dating to the Santonian age of the Cretaceous period.

The Alamyshik Formation is a geological formation in Kyrgyzstan whose strata date back to the Albian stage of the Early Cretaceous. Pterosaur remains are among the fossils that have been recovered from the formation.

<i>Omma</i> Genus of beetles

Omma is a genus of beetles in the family Ommatidae. Omma is an example of a living fossil. The oldest species known, O. liassicum, lived during the final stage of the Triassic (Rhaetian), over 200 million years ago, though the placement of this species in Omma has been questioned. Numerous other fossil species are known from the Jurassic and Cretaceous of Europe and Asia. The only living species is Omma stanleyi, which is endemic to Australia. Three other extant species endemic to Australia that were formerly part of this genus were moved to the separate genus Beutelius in 2020.Omma stanleyi is strongly associated with wood, being found under Eucalyptus bark and exhibiting thanatosis when disturbed. Its larval stage and many other life details are unknown due to its rarity. Males are typically 14–20 mm in length, while females are 14.4-27.5 mm. Omma stanleyi occurs throughout eastern Australia from Victoria to Central Queensland.

<span class="mw-page-title-main">Chresmodidae</span> Extinct family of insects

Chresmodidae is an extinct family of Mesozoic insects within the superorder Polyneoptera.

The Sierra Madre Formation is a geologic formation in Chiapas state, southern Mexico. It consists of marine dolomites and limestones. The formation dates to the Middle Cretaceous, spanning from the Aptian of the Early to the Cenomanian of the Late Cretaceous.

<i>Allkaruen</i> Genus of breviquartossan pterosaur from the Jurassic period

Allkaruen is a genus of "rhamphorhynchoid" pterosaur from the Early Jurassic Cañadon Asfalto Formation in Argentina. It contains a single species, A. koi.

Mesoblattinidae is an extinct family of cockroaches known from the Mesozoic. It was formerly considered a wastebasket taxon for Mesozoic cockroaches, but the family has subsequently been better defined, with many taxa transferred to Caloblattinidae. It is considered to have close affinities with Blattidae and Ectobiidae, as well as possibly Blaberidae. The family first appeared by the Early Jurassic. They are considered to represent amongst the oldest groups of modern cockroaches, and like them are thought to have laid oothecae.

Liberiblattinidae is an extinct family of cockroaches known from the Jurassic to Cretaceous. Some taxa, like Cryptoblatta and Hydrokhoohydra, are suggested to be semiaquatic. Spongistoma is suggested to be a nectarivore due to its unique sucking/sponging "proboscis" mouthparts. Some authors have suggested that the family is ancestral to Mantodea.

<i>Umaltolepis</i>

Umaltolepis is an extinct genus of seed plant, known from the Early Jurassic to Early Cretaceous of Asia. Within the form classification system used within paleobotany, it refers to the seed-bearing reproductive structures, which grew on woody plants with strap-shaped Ginkgo-like leaves assigned to the genus Pseudotorellia.

References

  1. Bakhar Formation at Fossilworks.org
  2. Sinitshenkova, 1987
  3. Vršanský, 2020
  4. Bakhurina & Unwin, 1995
  5. Barret et al., 2008
  6. Kostina et al., 2015

Bibliography