Doumu Fm
Type Locality and Naming
The naming section is located in an area from Doumu to the vicinity of Lianhuattang ~6 km north of Huangpu, Qianshan County, Anhaui. Named by the No. 331 Geological Party of Anhui Bureau of Geology in 1971 and formally used in the paper “Paleocene Containing Mammal Fossils in Anhui” (Qiu Zhanxiang et al., 1977).
Lithology and Thickness
According to the lithology, the formation may be divided into two members: Lower member is purplish red sandstone with conglomerate and sandy mudstone; Upper member is purplish red conglomerate, sandstone and pebbly sandstone. The rocks are poorly sorted and the gravels contained become larger in size and poorer in roundness up-section. From west to east the thickness has a tendency to increase, being generally ~600 m thick and reaching a maximum thickness of 1000 m.
Relationships and Distribution
Lower contact
Many geologists think that this formation has a conformable contact with the underlying early Paleocene Wanghudun Fm, but some geologists believe that it has an erosional unconformable contact with the underlying strata locally.
Upper contact
Its top is probably in conformable or disconformable with the late Paleocene Shuangtaxi Fm (Shuangta Fm).
Regional extent
It is mainly distributed at Yangxiaowu, Doumu, Hanhuawu and Lianhuatang northwest of Qianshan County and Yujiajing and Yuantanpu to the north, and similar outcrops may be present at Guizhen, Tongcheng County.
GeoJSON
Fossils
In the Doumu fauna ~15 species of fossils have been found now. The lower member contains less fossils, about six species, mainly the lizards Anhuisaurus huainanensis, the turtles Anhuichelys tsienshanensis, the mammals Hsiuannania tabiensis, Allictops inserrata, Mimotona robusta and Obtususdon hanhuensis; the upper member contains more than eight species of vertebrates, including the lizard Tinosaurus doumuensis, the turtles Anhuichelys sp. and the mammals Hsiuannania sp., Heomys orientalis, Mimotona wana, Hyracolestes ermineus, Sinostylops promissus and Archaeolambda tabiensis.
Age
Depositional setting
It is generally considered that the formation is fluvial-piedmont deposits.
Additional Information