Badaowan Fm
Type Locality and Naming
Junggar and Turfan-Hami Basins. It was named by the Geological Survey Division under the Xinjiang Petroleum Administration in 1956, and was first cited publicly by Si Xingjian and Zhou Zhiyan in 1962. The naming section is located 3-4 km southeast of the Badaowan to the north of Urumqi City, with the section on the Manas River serving as its reference section. Lowermost formation in Shuixigou Gr.
Synonym: (八道湾组)
Lithology and Thickness
This formation is composed of grey-green and dark-grey sandstones, alternate layers of sandy mudstone and shale, and is divided into the following three parts: Lower part, consisting of grey-green, and dark-grey sandstone, sandy mudstone and shale alternate layers, associated with thin-bedded limonite and three coal layers; Middle part, consisting of grey-green sandstone, sandy shale and pure shale, containing three coal layers; Upper part, consisting of grey-green and dark-grey thick-bedded sandstone, shale and three coal layers, with no top and basal parts having been found, and with a thickness of 663 m.
Relationships and Distribution
Lower contact
At the reference section, the basal part of the particular formation is in a disconformable contact with the underlying Xiaoquangou Gr (T2-3).
Upper contact
Its top part is in a conformable contact with the overlying Sangonghe Fm
Regional extent
It is distributed in the Junggar, Turufan-Hami and Santanghu Basins. In the area of the Baiyanghe-Heshitouluogai district on the northern margin of the Junggar Basin, the deposits are changing from coarse-grained ones on the west into fine-grained ones on the east. In the Karamay area, there occur four cycles of conglomerate-sandstone-mudstone intercalated with coal seams; in the Tostai-Urumqi area on the southern margin of the basin, the amount of mudstone is increasing, being intercalated with coal seams and siderite; and in the Sangequan-Shaqiuhe area and on the southern foothill of the Karameli Mts, the particular formation is thinning to be of 30-50 m, and represents conglomerate intercalated with sandstone and mudstone; and to the north of the Turufan-Hami Basin, as well as on the western margin of the basin, the formation is composed of coarse clastics, with its poor development on both the southern and northern margins of the basin, and with a still much more poor coal-bearing capacity of it.
GeoJSON
Fossils
The Badaowan Fm yields plant fossils as represented by Coniopteris hymenophylloides, Cladophlebis gigantea, Phoenicopsis speciosa, and Podozamites lauceolatus; bivalves such as Ferganoconcha subcentralis, F. tomiensis, Sibireconcha jenicejensis, Cuneopsis johannisboehmi, Unio khomentowski, U. shuixigouensis, Waagenoperna lilingensis, W. mytiloides, and W. cf. lilingensis.
Age
Depositional setting
The particular formation represents fluvial and swamp-facies deposits.
Additional Information