Jaisalmer Formation
| Jaisalmer Formation | |
|---|---|
| Stratigraphic range: Middle-Late Jurassic, | |
 An outcrop of the Jaisalmer Formation which is the type locality for Tharosaurus indicus. Photographed between 2019-21. | |
| Type | Geological formation |
| Sub-units | Badabag Member, Fort Member, Hamira Member, Jajiya Member, Joyan Member, Kuldhar Member |
| Underlies | Baisakhi Formation |
| Overlies | Lathi Formation |
| Thickness | Variable, typically 120–170 km (75–106 mi) |
| Lithology | |
| Primary | Siltstone, sandstone |
| Other | Limestone |
| Location | |
| Coordinates | 26°54′42″N 70°55′23″E / 26.911661°N 70.922928°E |
| Country |  India |
| Extent | Jaisalmer |
| Type section | |
| Named for | Jaisalmer, India |
| Named by | Richard Dixon Oldham |
| Year defined | 1886[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]
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[edit]
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[edit]
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 comprised mainly of lagoons, shoals and open marine environments.[7]
Paleofauna[edit]
![[icon]](/wiki/File:Wiki_letter_w_cropped.svg){kind=small} | This section needs expansion. You can help by adding to it. (August 2022) |
Dinosaurs[edit]
| Dinosaurs of the Jaisalmer Formation | ||||
|---|---|---|---|---|
| Genus | Species | Material | Notes | Photos |
| Turiasauria indet.[6] | Fragmentary tooth | Possibly the oldest Turiasaur | ||
| Averostra indet.[8] | isolated tooth | A possible Ceratosaur or a Non Spinosaurid Megalosauroid | ||
| Spinosauridae Indet.[9] | Pedal ungual phalanx | Possibly the oldest Spinosaurid |  | |
| Tharosaurus[10] | T. indicus | Partial cervical, dorsal, and caudal vertebrae and a dorsal rib | Oldest Dicraeosaurid and oldest Diplodocoid |
|
Other Reptiles[edit]
| Reptiles of the Jaisalmer Formation | ||||
|---|---|---|---|---|
| Genus | Species | Material | Notes | Photos |
| Crocodylomorpha | Indeterminate | Scutes | ||
| Reptilia | Indeterminate | Teeth | A possible Marine reptiles | |
Ichnofossils[edit]
- (?)Bichordites sp. – "Ichnofossils"[11]
- Cytherella indica[12]
- Micropneumatocythere joyanensis[12]
- Planolites .sp – "Ichnofossils"[11]
- Progonocythere khoslai[12]
- Rhizocorallium irregulare – "Ichnofossils"[11]
- Rhizocorallium jenense – "Ichnofossils"[11]
- Taenidium serpentinum – "Ichnofossils"[11]
- Thalassinoides .sp – "Ichnofossils"[11]
- Trichordis minuta[12]
Sharks[edit]
- Strophodus jaisalmerensis
- Strophodus indicus[13]
- Strophodus magnus[13]
- Strophodus medius[13]
- Planohybodus sp.[13]
References[edit]
- ^ a b Oldham, R.D., (1886). Preliminary note on the geology of northern Jaisalmer. Record Geological Survey of India, 19,157-160.
- ^ a b c 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.
- ^ 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.
- ^ a b 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) - ^ Narayanan, K., Subrahmanyan, M., Srinivasan, S., (1961). Geology of Jaisalmer. Unpublished report, Oil and Natural Gas Corporation Dehradun, India.
- ^ a b Sharma A, Singh S, Satheesh SR (2022). "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. 304 (2): 187–203. doi:10.1127/njgpa/2022/1064. S2CID 249030842.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ a b c d e f 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
- ^ a b c d Kumari, M. (2023). "Middle Jurassic Ostracodes from Joyan Member, Jaisalmer Formation, Jaisalmer, Rajasthan, India". Paleontological Journal. 57 (7): 775–783. doi:10.1134/S0031030123070055.
- ^ a b c d 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.