Wudaoling Fm
Type Locality and Naming
The type section is located in the Wudaoling area, Xiaoling Region, Archeng City, Heilongjiang Province. It was named by Zheng Guangyuan in 1963, and was cited officially by the Compiling Group for the Regional Stratigraphic Chart of the Heilongjiang Province (1979).
Lithology and Thickness
Volcaniclastics. In the naming locality, the base is grey-green andesitic porphyrite. Lower part is composed of grey-green and grey-black intermediate-acidic volcaniclastic rocks and their tuffs, intercalated with sandstone and carbonaceous slate, yielding plant fossils (phytolites). Middle part is composed of grey-green andesitic porphyrite and its tuffaceous lava and welded tuff. Upper part is composed mainly of rhyolitic tuffaceous lava and sandy slate. In the formation the sedimentary rocks are reducing in amount and the volcaniclastic rocks are increasing remarkably in amount in ascending order, with the basal volcaniclastic rocks and the normal sedimentary rocks being interbedded with one another, and with the intermediate volcaniclastic rocks having been replaced upwards by acidic lavas gradually to constitute a complete effusion cycle. Its maximum thickness is of 2220 m.
Relationships and Distribution
Lower contact
Uncertain in type section, where it is in fault contact with the metamorphosed fine-grained sandstone of the underlying Tumenling Fm. In the Anbang area of Tieli County the formation and its underlying Sanjiaoshan Fm represent continuous deposits.
Upper contact
Unconformable contact with the overlying Middle Jurassic Series in type section. But regionally, the next higher unit is the Hongshan Fm sandstone.
Regional extent
Distributed largely in the Binxi area of Bixian County, the Fu’antun, Xuhuatun and Xiweizi areas of Shangzhi City, the Qiupigou, Wudaoling, the Shanhe Forest Center in the southern part of the Yuquan Spring area of Archeng City, the Nianzigou area and West Tumen Ridge on the northern bank of the Mongniu River of Wuchang City.
GeoJSON
Fossils
Yields Plant fossils (phytolites) such as Paracalamites, Pecopteris, Calamites and Annularia.
Age
Depositional setting
It is interpreted as effusive continental volcanic activity.
Additional Information