Xiayang Fm
Type Locality and Naming
Beibu Gulf region. Named in 1965 by the Fourth Census Exploration Team of the Ministry of Geology. The named section is located in the 749 to 892.44 m drill section of Leiqiong Sanjing Xiayang, Xuwen County, Guangdong.
Lithology and Thickness
The Xiayang Formation refers to the coarse clastic rocks located between the Weizhou Fm and the Jiaowei Fm in the Leiqiong Depression. Its lithology and thickness vary greatly. The lithology can be divided into two sections. The Lower section is gray-green or gray fine sandstone and glutenite with thin mudstone; the Upper section is gray or light gray-green grayish bioclastic feldspar-quartz sandstone, conglomerate sandstone and dark gray mudstone. The thickness is 143.44 m. Oblique bedding, cross-bedding, agitated structure and wormhole develop in this Formation.
Relationships and Distribution
Lower contact
It is in pseudo-conformity contact with the underlying Oligocene Weizhou Fm.
Upper contact
It is in conformity contact with the overlying Miocene Jiaowei Fm.
Regional extent
The Xiayang Formation is distributed in the Beibu Gulf, Leizhou Peninsula, and northern Hainan Island. In the Leiqiong area, the lithology becomes finer and thinner from the northwest to the southeast. In the Beibu Gulf and Leiqiong areas, the thickness of this group is 62-717m, generally about 200m.
GeoJSON
Fossils
This Formation contains foraminifera, ostracods, gastropods, bivalves, barnacles, pollen and calcareous nannofossils. Planktonic foraminifera include Globigerina ciperoensis, Casigerinella chipolensis, Globigerinatella insueta, and benthic foraminifera Ammonia tepida, etc., belonging to the N4-N7 zone; the calcareous nannofossils only appear in the upper part of this Formation, mainly Helicosphaera ampliaperta, Discoaster deflandrei, Cyclicargalithus floridanus, etc., which correspond to the NN3-NN4 zone; the pollen is Tricolporopolodipollenites-Zonocostlisatites- Chenopodipollenites-Zonocostlisatites- Graminidites combination.
Age
Depositional setting
Littoral deposits
Additional Information