Hongliuyuan Fm
Type Locality and Naming
The type section is located 9.5 km southwest of the Liuyuan Station of the Lanzhou-Xinjiang Railway, Anxi, Gansu. It was named by the No. 1 Gansu Party of Regional Geological Survey in 1966.
Lithology and Thickness
Sandstone, Limestone and Volcanics. It is formed by clastic rocks intercalated with limestone and volcanic rocks. The Lower part consists of gray-green and gray-purple conglomerate, pebbled coarse-grained sandstone and feldspar-rich greywacke. The Upper part is dominated by gray and gray-black limestone and calcareous sandstone, locally intercalated with rhyolite, basalt and tuff. Thickness 337−2661 m. From west to east, volcanic rocks are decreasing while limestones are increasing.
Relationships and Distribution
Lower contact
Unconformity onto underlying granites. Coeval with Bashan Fm volcanics.
Upper contact
Disconformable contact with the overlying Shibanshan Fm
Regional extent
Distributed at places such as east of the Hongliu dried gully and Daqi Mt., south of Mazong Mt.
GeoJSON
Fossils
The Corals can be divided into two assemblage zones: a lower Arachnolasma sinense-Palaeosmilia murchisoni–Lophophyllum ashfellense assemblage zone, and an upper Gangamophyllum (Chienchangia) hamiense-Neoclisiophyllum assemblage zone. It also yields Brachiopods Gigantoproductus giganteus, G. latissimus, G. edelburgensis, Striatifera striata, Kansuella maxima, etc. and Ammonoid Eumorphoceras sp.
Age
Depositional setting
It is interpreted as neritic clastic and carbonate sediments
Additional Information