The Tiourarén Formation is a geological
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondar ...
in the
Agadez Region
Agadez Region is one of the seven regions of Niger. At , it covers more than half of Niger's land area, and is the largest region in the country, as well as the largest African state subdivision. The capital of the department is Agadez.
Histo ...
of Niger whose strata were originally thought to be
Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.
Geology
Pro ...
. However, re-interpretation of the sediments showed that they are probably
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...
(
Bathonian
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age.
Strat ...
) in age.
[Rauhut and Lopez-Arbarello (2009). "Considerations on the age of the Tiouaren Formation (]Iullemmeden Basin
The Iullemmeden Basin (Berber language: Iwellemmedden) is a major sub-Saharan inland basin in West Africa, extending about north to south and east to west. It covers western Niger and parts of Algeria, Mali and Nigeria. It is named after the Iu ...
, Niger, Africa): Implications for Gondwanan Mesozoic terrestrial vertebrate faunas." ''Palaeogeography, Palaeoclimatology, Palaeoecology'', 271: 259-267.[Tuiguidit foreland]
at Fossilworks
Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...
.org It is the uppermost unit of the
Irhazer Group. Dinosaur remains are among the fossils that have been recovered from the formation.
[Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 571-573. .]
Description
The formation comprises reddish, almost solid mudstones, which also shows grey and white streaks, probably caused by alternating oxidative and reducing environments. The
depositional environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be ...
has been interpreted as
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
y with seasonal flooding in
braided river
A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, ''aits'' or ''eyots''.
Braided streams tend to occur in rivers with high sediment l ...
systems.
[
]
Fossil content
See also
* List of dinosaur-bearing rock formations
This list of dinosaur-bearing rock formations is a list of geologic formations in which dinosaur fossils have been documented.
Containing body fossils
* List of stratigraphic units with dinosaur body fossils
** List of stratigraphic units with few ...
* Lists of fossiliferous stratigraphic units in Africa
These lists of fossiliferous stratigraphic units in Africa enumerate the rock layers which preserve the fossilized remains of ancient life in Africa by the modern countries wherein they are found.
Geographical atlas
C ...
** List of fossiliferous stratigraphic units in Niger
This is a list of fossiliferous stratigraphic units in Niger.
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List of fossiliferous stratigraphic units
See also
* Lists of fossiliferous stratigraphic units in Africa
** List of fossiliferous stratigraphic units in Mali
* Geol ...
* Geology of Niger The geology of Niger comprises very ancient igneous and metamorphic crystalline basement rocks in the west, more than 2.2 billion years old formed in the late Archean and Proterozoic eons of the Precambrian. The Volta Basin, Air Massif and the Iu ...
References
Further reading
* A. F. d. Lapparent. 1960. Les Dinosauriens du "Continental intercalaire" du Saharal central he dinosaurs of the "Continental Intercalaire" of the central Sahara Mémoires de la Société géologique de France, nouvelle série 39(88A):1-57
* P. C. Sereno, A. L. Beck, D. B. Dutheil, H. C. E. Larsson, G. H. Lyon, B. Moussa, R. W. Sadleir, C. A. Sidor, D. J. Varricchio, G. P. Wilson, and J. A. Wilson. 1999. Cretaceous sauropods from the Sahara and the uneven rate of skeletal evolution among dinosaurs. Science 286:1342-1347
* P. C. Sereno, J. A. Wilson, H. C. E. Larsson, D. B. Dutheil, and H.-D. Sues. 1994. Early Cretaceous dinosaurs from the Sahara. Science 266(5183):267-271
* F. Witzmann, O. Hampe, B. M. Rothschild, U. Joger, R. Kosma, D. Schwarz, and P. Asbach. 2016. Subchondral cysts at synovial vertebral joints as analogies of Schmorl's Nodes in a sauropod dinosaur from Niger. Journal of Vertebrate Paleontology 36(2):e1080719:1-11
{{DEFAULTSORT:Tiouraren Formation
Geologic formations of Niger
Mesozoic Niger
Jurassic System of Africa
Middle Jurassic Africa
Bathonian Stage
Oxfordian Stage
Siltstone formations
Mudstone formations
Fluvial deposits
Paludal deposits
Paleontology in Niger
Formations