Jaisalmer Formation

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Jaisalmer Formation
Stratigraphic range: Middle-Late Jurassic, Bajocian–Oxfordian
Jaisalmer Formation Tharosaurus type locality.png
An outcrop of the Jaisalmer Formation which is the type locality for Tharosaurus indicus . Photographed between 2019-21.
Type Geological formation
Sub-unitsBadabag Member, Fort Member, Hamira Member, Jajiya Member, Joyan Member, Kuldhar Member
Underlies Baisakhi Formation
Overlies Lathi Formation
ThicknessVariable, typically 120–170 km (75–106 mi)
Lithology
Primary Siltstone, sandstone
Other Limestone
Location
Coordinates 26°54′42″N70°55′23″E / 26.911661°N 70.922928°E / 26.911661; 70.922928
Country India
ExtentJaisalmer
Type section
Named for Jaisalmer, India
Named by Richard Dixon Oldham
Year defined1886 [1]

The Jaisalmer Formation is a Middle to Late Jurassic-aged geologic formation located in India near the city of Jaisalmer that consists mainly of marine deposits. [2] The formation was first identified and defined by geologist Richard Dixon Oldham in 1886. [1]

Contents

Dinosaur remains are among the known fossils recovered from this formation. [3]

Strophodus jaisalmerensis , a hybodont, was named after this formation and the Jaisalmer District where its holotype was found. [4]

Sub-units

The Badabag, Fort, Joyan and Hamira members represent the Middle Jurassic Bajocian and Bathonian stages, [2] while the Jajiya and Kuldhar members represent the Middle Jurassic Callovian and the Late Jurassic Oxfordian stages. [2]

The Fort Member is the most extensively studied and consists of fine to medium grain sandstones and oolitic limestones. [5] The Badabag Member consists of intraformational conglomerate and is fossil bearing. [6]

Paleoenvironment

The Jaisalmer district of India is a landlocked district in the state of Rajasthan. However, during the Middle Jurassic, the Jaisalmer Formation was located on the Tethyan coast of Gondwanan India. A marine paleoenvironment is supported by the presence of Hybodont sharks. [4] The Kuldhar Member Limestone contained carbonate microfacies that also indicate a depositional environment composed mainly of lagoons, shoals and open marine environments. [7]

Paleofauna

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Sauropods

Sauropods of the Jaisalmer Formation
GenusSpeciesLocalityMaterialNotesPhotos
Turiasauria [6] indeterminateChandoo Village quarryFragmentary tooth.The oldest turiasaur.
Tharosaurus [8] T. indicusJethwai VillagePartial cervical, dorsal, and caudal vertebrae and a dorsal rib.Oldest dicraeosaurid and oldest diplodocoid.

Tharosaurus UDL.png

Theropods

Theropods of the Jaisalmer Formation
GenusSpeciesLocalityMaterialNotesPhotos
Spinosauridae [9] IndeterminateChandoo Village quarryPedal ungual phalanx.Possibly the oldest spinosaurid. Had affinities with spinosaurinae.
Specimen RAJ/JAIS/CVQS002 Pedal ungual phalanx from the Bathonian of Jaisalmer Basin, India. Specimen RAJ JAIS CVQS002.png
Specimen RAJ/JAIS/CVQS002
Averostra [10] indeterminateChandoo Village quarryIsolated tooth.A possible Ceratosaur or a Non Spinosaurid Megalosauroid or a Allosauroid.

Other Reptiles

Reptiles of the Jaisalmer Formation
GenusSpeciesLocalityMaterialNotesPhotos
Crocodylomorpha [6] IndeterminateChandoo Village quarryScutes.
Neodiapsida [6] [10] IndeterminateChandoo Village quarryTeeth.Either a sauropterygian, thalattosaurian, choristodere or an ichthyosauromorph.

Fish

Fishes of the Jaisalmer Formation
GenusSpeciesLocalityMaterialNotesPhotos
Hybodontiformes Indet. [11] Indeterminate
Strophodus S. jaisalmerensisJethwai villageTeeth.A hybodont shark.
S. indicus [12] Chandoo Village quarry
S. magnus [12] Chandoo Village quarry
S. medius [12] Chandoo Village quarry
Planohybodus P. aff. grossiconus [12] Chandoo Village quarryTeeth.A hybodont shark.
Osteichthyes [10] Indeterminate.Chandoo Village quarryTeeth and scales.Found along with an averostran tooth.
cf. Eomesodon [13] cf. Eomesodon sp.Jethwai VillagePrearticular dental plate and isolated teeth.Oldest East Gondwanan Pycnodont.

Crustaceans

Crustaceans of the Jaisalmer Formation
GenusSpeciesLocalityMaterialNotesPhotos
Cytherella [14] C. indica
Micropneumatocythere [14] M. joyanensis
Progonocythere [14] P. khoslai
Trichordis [14] T. minuta

Ichnofossils

References

  1. 1 2 Oldham, R.D., (1886). Preliminary note on the geology of northern Jaisalmer. Record Geological Survey of India, 19,157-160.
  2. 1 2 3 Ahmad, Faiz; Quasim, Mohammad Adnan; Ahmad, Abul Hasnat Masood (January 2021). "Review for "Microfacies and diagenetic overprints in the limestones of Middle Jurassic Fort Member (Jaisalmer Formation), Western Rajasthan, India: Implications for the depositional environment, cyclicity, and reservoir quality" . Geological Journal. 56 (1): 130–151. doi:10.1002/gj.3945/v1/review2.
  3. ↑ Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria , 2nd, Berkeley: University of California Press. Pp. 593–600. ISBN   0-520-24209-2.
  4. 1 2 Krishna Kumara, Sunil Bajpaib, Pragya Pandeya, Triparna Ghosha, Debasish Bhattacharya (2021). "Hybodont sharks from the Jurassic of Jaisalmer, western India". Historical Biology. 34 (6): 953-963. doi:10.1080/08912963.2021.1954920.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ↑ Narayanan, K., Subrahmanyan, M., Srinivasan, S., (1961). Geology of Jaisalmer. Unpublished report, Oil and Natural Gas Corporation Dehradun, India.
  6. 1 2 3 4 Sharma, Archana; Singh, Sanjay; S. R., Satheesh (2022-06-10). "The first turiasaurian sauropod of India reported from the Middle Jurassic (Bathonian) sediments of Jaisalmer Basin, Rajasthan, India" . Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen: 187–203. doi:10.1127/njgpa/2022/1064.
  7. ↑ Asjad, Shaikh; Khan, K. F.; Quasim, M. A.; Sachan, H. K.; Javed, Aashna (2023-11-06). "Microfacies and stable isotope analysis of Kuldhar Member Limestone (Callovian–Oxfordian), Jaisalmer Basin, western Rajasthan: implications for depositional environment and diagenetic evolution" . Carbonates and Evaporites. 38 (4): 81. doi:10.1007/s13146-023-00905-6. ISSN   1878-5212.
  8. ↑ Bajpai, S.; Datta, D.; Pandey, P.; Ghosh, T.; Kumar, K.; Bhattacharya, D. (2023). "Fossils of the oldest diplodocoid dinosaur suggest India was a major centre for neosauropod radiation". Scientific Reports. 13 (1). 12680. Bibcode:2023NatSR..1312680B. doi: 10.1038/s41598-023-39759-2 . PMC   10403599 . PMID   37542094.
  9. ↑ Sharma, A.; Novas, F. E.; Singh, S. (2023). "First Jurassic evidence of a possible spinosaurid pedal ungual from the Jaisalmer Basin, India". Rivista Italiana di Paleontologia e Stratigrafia. 129 (3): 653–670. doi: 10.54103/2039-4942/20032 .
  10. 1 2 3 Sharma, Archana; Hendrickx, Christophe; Singh, Sanjay (2023-01-23). "First Theropod Record from the Marine Bathonian of Jaisalmer Basin, Tethyan Coast of Gondwanan India". Rivista Italiana di Paleontologia e Stratigrafia. 129 (1). doi: 10.54103/2039-4942/18306 . ISSN   2039-4942. S2CID   256347914.
  11. ↑ Ghosh, T.; Swami, N. K.; Kumar, K.; Maurya, A. S.; Bajpai, S. (2024). "An assemblage of Middle Jurassic hybodonts from Jaisalmer Basin, western India". Historical Biology: An International Journal of Paleobiology. doi:10.1080/08912963.2024.2412131.
  12. 1 2 3 4 Sharma A, Singh S (2021). "A small assemblage of marine hybodont sharks from the Bathonian of the Jaisalmer Basin, India". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 301 (3): 317–333. doi:10.1127/njgpa/2021/1014. S2CID   239669413.
  13. ↑ Kumar, Krishna; Bajpai, Sunil; Ghosh, Triparna; Pandey, Pragya; Bhattacharya, Debasish (2022-12-01). "Oldest East Gondwanan pycnodont fishes (Neopterygii, Pycnodontiformes) from the Middle Jurassic (Bathonian) of Jaisalmer, western India" . PalZ. 96 (4): 795–804. doi:10.1007/s12542-022-00619-5. ISSN   1867-6812.
  14. 1 2 3 4 Kumari, M. (2023). "Middle Jurassic Ostracodes from Joyan Member, Jaisalmer Formation, Jaisalmer, Rajasthan, India". Paleontological Journal. 57 (7): 775–783. doi:10.1134/S0031030123070055.
  15. 1 2 3 4 5 6 Kulkarni, K.G., Borkar, V.D., Petare, T.J., (2008). Ichnofossils from the Fort Member (Middle Jurassic), Jaisalmer Formation, Rajasthan. Journal of the Geological Society of India, 71, 731-738
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