Dazhang Formation
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| Dazhang Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Underlies | Tantou Formation |
| Overlies | Gaoyugou Formation |
| Thickness | 373.2 m |
| Lithology | |
| Primary | Marl, oil shale, claystone and glutenite |
| Location | |
| Coordinates | 33°23′N 111°07′E / 33.39°N 111.11°E[1] |
| Region | Henan |
| Country | China |
| Extent | Tantou Basin |
  Dazhang Formation (China)  Dazhang Formation (Henan) | |
The Dazhang Formation (simplified Chinese: 大章组; traditional Chinese: 大章組; pinyin: Dàzhāng zǔ) is a geologic formation in China. It preserves fossils dating back to the late Paleocene, including those of plants and mammals.[2] The formation is primarily composed of interbedded marl, oil shale, claystone and glutenite. Depending on the section, the color of the mudstone may vary from green, red-brown or gray-black.[1]
Comprehensive comparison of the lithology and stratigraphy suggests the Dazhang Formation was deposited during the late Paleocene. This dating is further supported by fossil evidence, as standard Paleocene fossils such as those of the snails Parhydrobia xiaohegouensis and Opeas guangdongensis, and anagalid mammals. Palynological evidence based on large amounts of Paleocene palynomorphs (including Proteaceae and Ulmaceae) also supports a late Paleocene age for this formation.[1]