Wanglougang Fm

Beibu Gulf region. Named in 1960 by Team 765 of Guangdong Geological Bureau. The named section is located at drill hole CK4/4 of Wanglou Port, Jiusuo Town, Ledong County, Hainan; the reference section is located at No.1 drill in Zhushan, Xuqian, Xuwen County, Guangdong.

The famous Wanglougang Formation is a set of black-dark grey clay in the No. 4 drill hole of Wanglougang with a drill depth of 6.7 to 183.55 m, with interbedded silty clay and thin glutenite. It was later widely applied in the Leiqiong Depression and Beibu Gulf, representing the shallow sea fine clastic sediments with a transgressive sequence conformity above on the Foluo Formation or Dengloujiao Fm. The lithology of this group is fine at the bottom and thick at the top, forming an anti-rhythm. Lower section is light gray or gray-green silty mudstone, mudstone with light gray or gray-yellow sandstone, and conglomerate sandstone. In some areas, there are tuff and basalt. The mudstone has poor diagenesis, slightly calcareous, rich in bioclastics, and locally rich integrated bioclastic rock. Upper section is dominated by a large set of gray or gray-yellow sandy conglomerate and conglomerate, with a small amount of gray mudstone, and the sandstone is loosely cemented and poor in sorting. The lithology and thickness vary greatly, from the southwest to Qiongbei, the lithology becomes thicker and the thickness becomes smaller; from the northwest of the Leizhou Peninsula to the southeast, the lithology becomes finer and thinner. The thickness is 18 to 511.5m.

Contains planktonic foraminifer Globigerinoides extrimus, Globorotalia menardii, G.multicamerata, Globigerina nepenthes, Pulleniatina obliqueloculata, etc., belonging to the N18-N21 zone, and the benthic species Aserocotalia spp., Pseudorotalia spp., Bigenerinanodosaria, etc., The rich ostracods records include Hemikrither foveata-Neomonoceratina delicata combination; pollen is the Cupuliferoipollenites-Polypodiaceaesporites-Chenopodipollis combination, in addition, it also contains gastropods, bivalves, bryozoans, etc.

Coastal and neritic deposits