Ntawere Formation
Ntawere Formation | ||
---|---|---|
Ma | ||
Type | Approximate paleocoordinates 53°36′N 20°36′E / 53.6°N 20.6°E | |
Region | Eastern Province | |
Country | Zambia | |
Extent | Luangwa Basin | |
The Ntawere Formation is a
Geology
Several different facies are present in the Ntawere Formation, reconstructing a floodplain environment. The coarsest facies are trough cross-bedded conglomeratic sandstone full of mineral concretions. These coarse deposits formed in ancient channels such as riverbeds. Another type of facies involves thick beds of mudstone interbedding with thinner layers of fine-grained sandstone, indicating alternating low- and high-energy water flow within the channels. Graded sandstone to mudstone overbank deposits (complete with ripple marks) occur near channel deposits. Extensive successions of laminated or massive mudstone are common, often containing slickensides, calcareous nodules or layers (marls), and/or hematite nodules. These types of thick mud/marl layers likely formed in more quiet parts of the floodplain isolated from turbulent channels.[1]
The floodplain was seemingly more active during the deposition of the Lower Ntaware Formation, as coarser sandstone channel fills are prevalent in that section while extensive mudstone layers are more common in the Upper Ntaware Formation. Fossils are typically found preserved in calcareous nodules in the mudstone of the Upper Ntaware, although they occur in some parts of the Lower Ntaware as well. The Ntaware Formation is an example of red beds, which are typically deposited in warm environments with seasonal ponds and rivers tied to wet and dry seasons.[1]
Paleobiota
Invertebrates
Invertebrates of the Ntawere Formation | ||||||
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Taxon | Member | Material | Notes | |||
Unio karooensis | Upper Ntaware | Shells | A freshwater bivalve
|
Fish
Fish of the Ntawere Formation | ||||||
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Taxon | Member | Material | Notes | |||
Hybodontoidei indet. | Upper Ntaware | Fin spines | An indeterminate non- | |||
Ptycoceratodontidae indet. | Lower Ntaware, Upper Ntawere | Tooth plates | An indeterminate lungfish, similar to Ptychoceratodus |
Amphibians
Amphibians of the Ntawere Formation | ||||||
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Taxon | Member | Material | Notes | Images | ||
Batrachosuchus concordi
|
Upper Ntaware | A skull and forelimbs | A stereospondyl
|
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Cherninia megarhina
|
Upper Ntaware | A partial skull | A stereospondyl
| |||
"Stanocephalosaurus" pronus | Upper Ntaware | A skull | A new species of capitosauroid , likely not part of the genus Stanocephalosaurus
| |||
Stereospondyli indet. | Upper Ntaware | Vertebrae and part of a jaw | Indeterminate stereospondyl material. The jaw fragment may belong to a rhytidosteid
|
Synapsids
Synapsids of the Ntawere Formation
| ||||||
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Taxon | Member | Material | Notes | Images | ||
Cricodon metabolus
|
Upper Ntaware | A partial skeleton | A cynodont
|
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Cynognathus crateronotus
|
Lower Ntaware | Teeth, | A cynodont
| |||
Diademodon tetragonus
|
Lower Ntaware | A skull | A cynodont
| |||
"Kannemeyeria" latirostris | Lower Ntaware | A skull | A dicynodont, possibly a species of Kannemeyeria or Dolichuranus
| |||
Kannemeyeria lophorhinus
|
Lower Ntaware | A skull | A dicynodont
| |||
Luangwa drysdalli
|
Upper Ntaware | Skulls and postcranial material | A cynodont
| |||
Sangusaurus edentatus
|
Upper Ntaware | A partial skull | A dicynodont
| |||
Traversodontidae sp. | Upper Ntaware | Skulls and postcranial material | An unnamed species of cynodont
| |||
Zambiasaurus submersus
|
Upper Ntaware | A skull fragment | A dicynodont
|
Archosauromorphs
Archosauromorphs of the Ntawere Formation
| ||||||
---|---|---|---|---|---|---|
Taxon | Member | Material | Notes | Images | ||
Archosauriformes indet. | Upper Ntaware | Teeth | Various indeterminate large carnivorous archosauriforms, likely loricatans | |||
Archosauromorpha indet. | Upper Ntaware | A neck vertebra | An indeterminate archosauromorph, possibly an allokotosaur
| |||
Dinosauriformes indet.
|
Upper Ntaware | A partial fibula | A large silesaurid
| |||
Loricata indet. | Upper Ntaware | Vertebrae | An indeterminate large archosaur, similar to Stagonosuchus | |||
Lutungutali sitwensis
|
Upper Ntaware | An ilium | A basal silesaurid
| |||
Shuvosauridae indet. | Upper Ntaware | Part of a femur | An indeterminate poposauroid "
| |||
Silesauridae indet. | Upper Ntaware | A maxilla, femurs, and material from the hip, ankle, and foot | Indeterminate basal silesaurid material comparable to Asilisaurus and Lutungutali
|
See also
- Donguz Formation, contemporaneous fossiliferous formation of Russia
- Ermaying Formation, contemporaneous fossiliferous formation of China
- Manda Formation, contemporaneous fossiliferous formation of Tanzania
- Omingonde Formation, contemporaneous fossiliferous formation of Namibia
- Río Seco de la Quebrada Formation, contemporaneous fossiliferous formation of Argentina
- Yerrapalli Formation, contemporaneous fossiliferous formation of India
References
- ^ S2CID 133878741.
Further reading
- K. D. Angielczyk, J. S. Steyer, C. A. Sidor, R. H. H. Smith, R. L. Whatley and S. Tolan. 2014. Permian and Triassic Dicynodont (Therapsida: Anomodontia) Faunas of the Luangwa Basin, Zambia: Taxonomic Update and Implications for Dicynodont Biogeography and Biostratigraphy. In C. F. Kammerer, K. D. Angielczyk and J. Fröbisch (eds.), Early Evolutionary History of the Synapsida 93-138
- A. R. Drysdall and J. W. Kitching. 1963. A re-examination of the Karroo succession and fossil localities of part of the Upper Luangwa Valley. Memoir of the Geological Survey of Northern Rhodesia 1:1-62