Daijiaping Fm
Type Locality and Naming
Hengyang Basin. The Daijiaping Formation was established by the Hunan Regional Geological Survey Team in 1962. The section designated is at Daijiaping of the Hengdong County, Hunan. The reference section is from Daijiaping-Nanshuichong of the Hengshan County.
The Daijiaping Formation is dominated by purple red thick-bedded sandstone and conglomerate and upward brown red sandstone, siltstone and mudstone, which was assigned to the Paleogene. In 1964 the Hunan Regional Geological Survey Team reassigned it to Late Cretaceous.
Lithology and Thickness
The Daijiaping Formation comprises a set of purple red clastic sediment rhythms, which is divided into two members. Lower member is built up by brown red massive conglomerate, sandstone, sandy conglomerate, sandstone and siltstone which grade upward into mudstone with siltstone and variegated mudstone, bearing floras and faunas. Upper member is built up by purple red mudstone with siltstone and yellow green mudstone. It is 609 m thick.
Relationships and Distribution
Lower contact
It is continuous or disconformable with the underlying Shenhuangshan Fm, and locally overlaps the granite, the Upper Devonian Shetianqiao Fm. At the type section, the base built up by brown red massive conglomerate is differentiated from the underlying biotite granite.
Upper contact
Its top is bounded by the purple red gravel-bearing grit at the base of the Chejiang Fm. It lies conformably or disconformably under the Dongtang Fm (now named as Chejiang Fm).
Regional extent
The formation mainly occurs in the vast area of east Hunan. It is quite persistent in lithology and 1912 m thick in the Hengyang basin. In the Chashui basin, it is mainly characterized by the appearance of purple red conglomerate interbedded with sandstone, with a thickness of 2356 m. In the Liyou basin, it is mainly built up by purple red conglomerate, sandy conglomerate, sandstone, siltstone and clayey siltstone. It ranges from 1274.1 to 2880 m in thickness. It is called the Fenshuiao Fm in north Hunan and the Xiaodong Fm and the Jinjiang Fm in west Hunan.
GeoJSON
Fossils
Lower member contains ostracods Cypridea spongvosa, Mongolianella sp., Candona sp., and sporopollen. Upper member yields ostracods Cypridea cavernosa, C. tera, Tylicypridea amoena, C.chinensis, C.gigantea, Candona hunanensis; Charophytes Porochara anluensis, Lactochara brevis, Sphaerochara parvala, etc. In the Liyou basin, it contains abundant fossils including ostracods Talicypridea amoena, Cypridea cavernasa; Dinosaurian eggs Oolithes elongatus, and Dinosaurua.
Age
Depositional setting
The formation is of continental freshwater facies.
Additional Information