Lingfeng Fm
Type Locality and Naming
Depressions north of Taiwan. The naming section is located in Lingfeng No. 1 well of the Oujiang depression in the East China Sea continental shelf basin at 129º58′24"E and 27º02′40"N; the reference section is located in Shimentan No. 1 well. Named by the Shanghai Comprehensive Marine Geological Party, former Ministry of Geology and Mineral Resources in 1987.
Lithology and Thickness
The Lingfeng Formation refers to a sequence of dark gray mudstone below coal measures above the Shimentan Fm. It takes the 2292–2488 m interval of Lingfeng No. 1 well as the stratotype section. Large quantities of foraminifera, dinoflagellates, calcareous nannofossils, ostracods and sporopollen are found in mudstone of this formation. According to analysis of seismic wave groups, its top is T41 wave and its lower part directly overlaps on gneiss in the Proterozoic Wendong Gr in Lingfeng No. 1 well, whereas in Shimentan No. 1 well its base is bounded by T50 unconformity. The age is mid-late Paleocene and the apparent thickness is 196 m. Lithologically, it may be subdivided into the upper and lower members. Lower member is gray mudstone and grayish white lime, silty and fine sandstone; the base is 2 m thick light gray bioclastic limestone; Upper member is light gray silty and fine sandstone and coarse sandstone and dark gray or grayish black mudstone. The thickness of this formation is 200–700 m, reflected by the seismic wave T41 group to T50.
Relationships and Distribution
Lower contact
This formation has an unconformable contact with the underlying Paleocene Shimentan Fm or Wengdong Gr.
Upper contact
Conformable contact with the overlying Mingyuefeng Fm.
Regional extent
Its distribution is controlled by downfaulting. Regionally the thickness of sediments decreases from south to north. It is most complete and typical in Shimentan No. 1 well, and has been partly eroded in Mingyuefeng No. 1 well and mostly eroded in Wenzhou No. 6-1-1 well.
GeoJSON
Fossils
It contains abundant marine fossils. The benthic foraminifera are represented by the Silicosigmoilina-Spiroplectammina assemblage. Their associated planktic foraminifera are Muricoglobigerina soldadoensis, Globorotalia (M.) angulata, G. (G.) pseudomenardii and Subbotina linaperta, belonging to zones P3–P6. Ostracods are characterized by the Cytherella-Krithe assemblage. The calcareous nannofossils are NP4–NP9, the main elements are Fasciculithus tympaniformis, Prinsius bisulcus, Heliolithus kleinpellii and Discoaster multiradiatus. The dinoflagellates are the Apectodinium homomorphum-Ceratiopsis speciosa assemblage. The sporopollen is Lingfenpollis-Momipites-Taxodiaceaepollenites assemblage.
Age
Depositional setting
This formation is littoral deposits
Additional Information