Hepu Fm
Type Locality and Naming
It was named by the Guangxi Party of Regional Geological Survey in 1977 (please see Lin Baoyu, 1979). The type section is located at Niuliaodi of Shiwanxu, 12-15 km north of the Hefu County seat.
Synonym: (合浦组)
Lithology and Thickness
It is 239 m in thickness, dominated by interbeds of violet grey pelitic siltstone with shale and silty shale. The lower part consists of grayish white, gray and grayish yellow pelitic siltstone and pelitic quartzose siltstone intercalated with shale; the base is composed of micritic sandstone.
Relationships and Distribution
Lower contact
The formation rests conformably in between the underlying Lingshan Gr
Upper contact
The formation rests conformably in between the overlying Fangcheng Gr
Regional extent
The group is restricted in distribution. Its lithology is rather monotonous in Yulin and Hepu of south Guangxi. It is 120-670 m in thickness and intercalated with quartzose sandstone. In the area from Qingzhou to Dongxin it is 585-670 m thick with coarser-grained lithology as dominated by quartzose sandstone intercalated with pelitic shale, and yields upper and lower siderite layers. The Hepu Fm, over 200 m in thickness, is merely exposed at Chiping Forest Farm, Cenxi County in southeast Guangxi with slightly coarser lithology. The base, over 200 m thick, consists of inequigranular quartzose sandstone and sandstone intercalated with shale.
GeoJSON
Fossils
The graptolite zones are in ascending order listed as follows: the Cyrtograptus angustus zone, the Cyrtograptus murchisoni zone, the Monograptus riccartonensis zone, the Pristiograptus dubius zone, and the Pristiograptus vulgaris zone. It bears also brachiopod, trilobite Coronocephalus sp., etc.
Age
Depositional setting
The Hepu Gr belongs to littoral-neritic facies developed with flysch-flychoid rhythmites.
Additional Information