Jaisalmer Formation | |
---|---|
Stratigraphic range: Middle-Late Jurassic, | |
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″N70°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]
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]
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]
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Color key
| Notes Uncertain or tentative taxa are in small text; |
Sauropods of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Turiasauria [6] | indeterminate | Chandoo Village quarry | Fragmentary tooth. | The oldest turiasaur. | |
Tharosaurus [8] | T. indicus | Jethwai Village | Partial cervical, dorsal, and caudal vertebrae and a dorsal rib. | Oldest dicraeosaurid and oldest diplodocoid. | |
Theropods of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Spinosauridae [9] | Indeterminate | Chandoo Village quarry | Pedal ungual phalanx. | Possibly the oldest spinosaurid. Had affinities with spinosaurinae. | |
Averostra [10] | indeterminate | Chandoo Village quarry | Isolated tooth. | A possible Ceratosaur or a Non Spinosaurid Megalosauroid or a Allosauroid. | |
Reptiles of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Crocodylomorpha [6] | Indeterminate | Chandoo Village quarry | Scutes. | ||
Neodiapsida [6] [10] | Indeterminate | Chandoo Village quarry | Teeth. | Either a sauropterygian, thalattosaurian, choristodere or an ichthyosauromorph. |
Fishes of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Hybodontiformes Indet. [11] | Indeterminate | ||||
Strophodus | S. jaisalmerensis | Jethwai village | Teeth. | 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 quarry | Teeth. | A hybodont shark. | |
Osteichthyes [10] | Indeterminate. | Chandoo Village quarry | Teeth and scales. | Found along with an averostran tooth. | |
cf. Eomesodon [13] | cf. Eomesodon sp. | Jethwai Village | Prearticular dental plate and isolated teeth. | Oldest East Gondwanan Pycnodont. |
Cephalopods of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Crustaceans of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
Cytherella [14] | C. indica | ||||
Micropneumatocythere [14] | M. joyanensis | ||||
Progonocythere [14] | P. khoslai | ||||
Trichordis [14] | T. minuta |
Brachiopods of the Jaisalmer Formation | |||||
---|---|---|---|---|---|
Genus | Species | Locality | Material | Notes | Photos |
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