Zhoutian Formation
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The Zhoutian Formation () is a
geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...
in
Jiangxi ; Gan: ) , translit_lang1_type2 = , translit_lang1_info2 = , translit_lang1_type3 = , translit_lang1_info3 = , image_map = Jiangxi in China (+all claims hatched).svg , mapsize = 275px , map_caption = Location ...
, China. It has been dated to the late
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
period, at about 96–90 Ma. Abundant
egg fossil Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...
s are known from the formation, in addition to dinosaurs such as ''
Datai ''Datai'' is an extinct genus of ankylosaurid dinosaur from the Late Cretaceous Zhoutian Formation of Jiangxi Province, China. The genus contains a single species, ''D. yingliangis'', which is known from the articulated skulls and partial skele ...
'' and '' Gandititan''. Invertebrate and plant fossils have also been described from the Zhoutian Formation.


Geology

Layers of the Zhoutian Formation are characterized by a consistent sandy
lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...
, typically with
mauve Mauve ( ; ) is a pale purple color named after the mallow flower (French: ). The first use of the word ''mauve'' as a color was in 1796–1798 according to the ''Oxford English Dictionary'', but its use seems to have been rare before 1859. ...
(reddish to purplish) hues. Most of the formation alternates between fine calcic
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
and
siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...
layers. In some places, other minerals are
interbedded In geology, interbedding occurs when beds (layers of rock) of a particular lithology lie between or alternate with beds of a different lithology. For example, sedimentary rocks may be interbedded if there were sea level variations in their sedimen ...
, such as
calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...
,
gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...
,
halite Halite ( ), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...
, and
mirabilite Mirabilite, also known as Glauber's salt, is a hydrous sodium sulfate mineral with the chemical formula Na2SO4·10H2O. It is a vitreous, colorless to white monoclinic mineral that forms as an evaporite from sodium sulfate-bearing brines. It is ...
. The Zhoutian Formation dates to around 96–90 million years ago, during the
Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...
–early
Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by ...
ages of the early
Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...
epoch within the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
period.


Stratigraphy

The Zhoutian Formation is the upper unit of the Ganzhou Group, overlying the Maodian Formation in that group. The Guifeng Group (beginning with the Hekou Formation) overlies the Zhoutian Formation. These two groups comprise the
Ganzhou Ganzhou (), alternately romanized as Kanchow, is a prefecture-level city in the south of Jiangxi province, China, bordering Fujian to the east, Guangdong to the south, and Hunan to the west. Its administrative seat is at Zhanggong District. His ...
Basin.


Paleoenvironment

The lower unit of the Zhoutian Formation is suggested to have had a predominantly hot-arid climate, punctuated by two cooling events. The upper unit was likely characterized by a predominantly warm-humid climate with frequent climate fluctuations. The environment has been interpreted as a shallow
lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...
(lake) system. While
oviraptorid Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one ...
body fossils have not been found in the Zhoutian Formation, they are among the most common dinosaur fossils found in other similar localities, in addition to occasional sauropod and hadrosaurid fossils.


Fossil content


Dinosaurs


Ootaxa


Invertebrates


Plants


See also

*
List of stratigraphic units with dinosaur body fossils This is a list of stratigraphic units from which dinosaur body fossils have been recovered. Although Dinosauria is a clade which includes modern birds, this article covers only Mesozoic stratigraphic units. Units listed are all either formation ra ...
*
List of stratigraphic units with dinosaur trace fossils This is a list of stratigraphic units dinosaur trace fossils have been recovered from. Although Dinosauria is a clade which includes the descendant taxon Aves (modern birds), this article covers only stratigraphic units containing Mesozoic forms. ...


References

{{Reflist Fossiliferous stratigraphic units of Asia Upper Cretaceous Series of Asia Geologic formations of China Cretaceous China Lacustrine deposits Sandstone formations Paleontology in Jiangxi Turonian Stage Coniacian Stage