The Ulansuhai Formation () is a geological
formation
Formation may refer to:
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Mathematics and science
* Cave formation or speleothem, a secondar ...
in Inner Mongolia, north China. Dinosaur remains are among the fossils that have been recovered from the formation.
[Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. .]
The Ulansuhai Formation has traditionally been considered to date to the
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...
-
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...
stages of the
Lower Cretaceous
Lower may refer to:
*Lower (surname)
*Lower Township, New Jersey
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*Lower Wick
Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...
, due to similarities between the Ulansuhai fauna and known Aptian formations.
However,
radiometric dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...
done on underlying formations has shown this to be incorrect. Due to the age of underlying rocks, the Ulansuhai Formation cannot be older than the
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...
stage of the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
, about 92 Ma.
[Kobayashi, Y., and Lu, J.-C. (2003). "A new ornithomimid dinosaurian with gregarious habits from the Late Cretaceous of China." ''Acta Palaeontol. Pol.'', 48: 235–259.][Benson, R.B.J. and Xu, X. (2008). "The anatomy and systematic position of the theropod dinosaur ''Chilantaisaurus tashuikouensis'' Hu, 1964 from the Early Cretaceous of Alanshan, People’s Republic of China."
''Geol. Mag.'', 145: 778–789. ]
Fossil content
Dinosaurs
Testudines
Ostracods
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 ...
References
{{Reflist
Geologic formations of China
Upper Cretaceous Series of Asia
Cretaceous China
Turonian Stage
Paleontology in Inner Mongolia