Yongxing Fm
Type Locality and Naming
South China Sea – Xisha islands. The type section is located at Xiyong Well No.2 in Xisha Islands ("Paracel Islands"), South China Sea. It was named and surveyed by Zhang M. in 1989.
NOTE: There is not a standardized regional lithostratigraphy for the Xisha islands; nor for the nomenclature in the reference wells.
Synonym: maybe lower Ledong Fm ?
Lithology and Thickness
It is characterized by the white and grayish white wackestone, marl, algal limestone and oncolytic limestone, framestones are occasionally present. Debris of Blue-green algae are abundant, oncolites are present in lower part; debris of red algae and algae mat layers are abundant, foraminifera fossils are present in upper part. The thickness is 125 m.
Relationships and Distribution
Lower contact
Yongxing Fm is unconformable in contact to underlying Yongle Fm.
Upper contact
Yongxing Fm is unconformable in contact to overlying Chenhang Fm (= Leodong Fm of other publications?).
Regional extent
GeoJSON
Fossils
Age
Depositional setting
It is interpreted as an atoll lagoon, reef flat lagoon environment.
Additional Information