Dikaner Fm
Type Locality and Naming
The type section lies 60 km southwest of Dikaner (41°50′30″N, 90°51′30″E), Xinjiang. It was named by Luo Fazuo in 1958, and cited in Regional Stratigraphical Scale of Xinjiang in 1981.
Lithology and Thickness
Volcanics and Volcaniclastics. Composed of marine intermediate and intermediate-acid volcanic lava and pyroclastic rock, and tuffaceous clastic rock, with minor clastic rock. At Shuiquangou southwest of Dikaner, it is dominated by dark-gray to yellow-green plagioclase-rich tuff, dacitic tuff, tuffaceous sandstone and tuffaceous siltstone, often in rhythmic interbeds and intercalated with plagioclase-rich porphyrite and dacitic porphyrite. Exposed thickness of 1966 m.
Lithologically, volcanic lavas increase eastward, turning to neritic normal clastic rocks in the Yamansu area, and volcanism is weakened. The thickness varies from 889.9 m to 2416 m, reaching the thickest at Aqi Mt.
Relationships and Distribution
Lower contact
Unconformable contact with the underlying Xiaorequanze Fm. Regionally, the formation is in unconformable or disconformable contact with the underlying Yamansu Fm.
Upper contact
Uncertain: The top is unexposed. Regionally, the formation is in unconformable or disconformable contact with the overlying Aqikbulak Fm.
Regional extent
Distributed in Qoltag, extending nearly E-N.
GeoJSON
Fossils
The siltstone in the lower part contains Brachiopods Spirifer sp. and Chonetes sp. Westward to Axakbulak, it contains Brachiopods Echinoconchus sp., Martinia sp., Marginifera sp. and Plicatifera sp., etc. Wastward to the Nandagou and Beidagou areas, it contains Fusulinids Qzawainella sp., Profusulinella sp., Eofululina sp., etc. At Matoutan it contains corals Caninia sp., Diphyphyllum sp., Bothrophyllum sp., etc.
Age
Depositional setting
It is interpreted as neritic eruptive rocks
Additional Information