Zhoutian Formation
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| Zhoutian Formation | |
|---|---|
| Stratigraphic range: Late Cretaceous (Turonian–early Coniacian), | |
.png) Outcrops of the Zhoutian Formation in Jiangxi | |
| Type | Geological formation |
| Unit of | Ganzhou Group |
| Underlies | Hekou Formation |
| Overlies | Maodian Formation |
| Thickness | Lower unit: 1,435–1,270 metres (4,708–4,167 ft) Upper unit: 1,270–1,100 metres (4,170–3,610 ft)[1] |
| Lithology | |
| Primary | Reddish siltstone, sandstone |
| Other | Interbedded halite |
| Location | |
| Coordinates | 25°30′26″N 115°46′34″E / 25.50722°N 115.77611°E |
| Region | Jiangxi Province |
| Country | China |
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The Zhoutian Formation (Chinese: 周田组; pinyin: zhōu tián zǔ) is a geological formation in Jiangxi, China. It has been dated to the late Cretaceous period, at about 96–90 Ma. Abundant egg fossils are known from the formation, in addition to dinosaurs such as Datai and Gandititan. Invertebrate and plant fossils have also been described from the Zhoutian Formation.
Stratigraphy
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Layers of the Zhoutian Formation are characterized by a consistent sandy lithology, typically with mauve (reddish to purplish) hues. Most of the formation alternates between fine calcic sandstone and siltstone layers. In some places, other minerals are interbedded, such as calcium, gypsum, halite, and mirabilite.[2][3][4] The Zhoutian Formation dates to around 96–90 million years ago, during the Turonian–early Coniacian ages of the early Late Cretaceous epoch within the Cretaceous period.[5]
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.[6] These two groups comprise the Ganzhou Basin.[7]
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.[1] The environment has been interpreted as a shallow lacustrine (lake) system.[8] While oviraptorid 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.[7]
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