Donggou Fm
Type Locality and Naming
Junggar Basin. Sun Jianliang erected the Donggou series in 1956. The type locality for the designation is in Donggou of the Hutubi County, Xinjiang. In the report on the geological survey made in the Changji river-Urumqi river area, Sun Jianliang called the red beds and the lower green bed above it the Donggou series, and assigned it to Late Cretaceous-Paleogene, which was openly published by the Xinjiang Regional Geological Survey Team (1965). In 1960 the third party of the Team called the red beds the Donggou Formation, and then the Donggou Group in 1965, which was assigned to Late Cretaceous -Eocene. The formation is assigned to Late Cretaceous in this lexicon.
Lithology and Thickness
The Donggou Formation is represented by brick red, brown red and gray brown conglomerate interbedded with sandstone and siltstone, intercalated with sandy mudstone, with abundant calcareous materials and a few number of calcareous nodules. The Donggou Formation is 420 m thick.
Relationships and Distribution
Lower contact
Its base is separated by a disconformity from the underlying Lianqinxin Fm by brown red conglomerate.
Upper contact
Its top comprising break red clayey siltstone and conglomerate with calcareous cementing matters is differentiated from the overlying Paleogene Ziniquanzi Fm in south Junggar Basin. The Donggou Formation is in disconformable and unconformable contact with the overlying Honglishan Fm in NW Junggar Basin.
Regional extent
The present formation mainly occurs on the first row structures and the monocline zone between the Changji county and the Shawan county on the southern margin of the Junggar basin. To the east of Urumqi, it occurs to the west of the Shuimohe and on the southwest limb of the paleo-grassland of the Fukang County. On the northwest margin it is seen in on the east bank of the Aili lake of Urhe and in Lijishan and Honglishan northwest of Karamay. On the southern margin of the basin, it becomes finer from the Jichang river westward to the Tugulu river, and then becomes coarser in Manas-Ziniquanzi. It thickens from west to east, generally ranging from 46 to 813 m. On the northwest margin the name of the Ailikhu Formation was once used. In Urhe it is represented by gray white quartz sandstone and conglomerate with brown and brown yellow sandy mudstone, which become finer in Xiazijie and then coarser eastward to the Delunshan area and range from 80 to 179 m in thickness.
GeoJSON
Fossils
The formation bears Dinosaurian eggs Oolithes elongatus; and Ostracods Talicypridea amoena, T. subglosa, T. obligua in the Dahonggou, Toutunhe and Manasihe areas of Fukang. In the Ailik lake area of Urhe on the northwest margin of the Junggar basin, it contains the representative elements of the early stage Hadrosauridae and ostracods.
Age
Depositional setting
It is of piedmont-fluvial facies deposition.
Additional Information