Shibanshan Fm
Type Locality and Naming
The type section is located at Shibanshan (Mt.), 78 km northeast of Dunhuang, Gansu. It was named by the No. 2 Gansu Party of Regional Geological Survey in 1973, and formally cited in 1979.
Lithology and Thickness
Sandstone, Claystone, Limestone and Volcaniclastics. A suite of littoral-neritic clastic and carbonate rocks intercalated with minor volcanic rocks. At the type section, it is composed of gray and dark-gray feldspar-rich quartz sandstone and silty slate, intercalated with conglomerate, pebbly sandstone, marble and bioclastic limestone. At Jijitaizi 82 km north of Jinta, it is of gray-black and gray-white moderately thick-bedded chert nodule-bearing limestone intercalated with thick-bedded crystalline limestone, occasionally with purple-red brecciated limestone, thickness >516 m.
Relationships and Distribution
Lower contact
conformable contact with the underlying Hongliuyuan Fm and Baishan Fm
Upper contact
conformable contact with the overlying Jijitaizi Fm
Regional extent
In the north zone, the formation outcrops at Shibanshan, Baijianshan, Hongliuyuan, Yin’aoxia, the Beishan Coalpit, etc.; while in the south zone only seen around Pochengshan and Yemaquan of Subei County in the western part. The west member in the south zone is dominated by clastic rocks, with limestone increasing eastward. In the north zone, represented by the Pochengshan section of Subei, it is composed of gray-green sandstone, slate and conglomerate intercalated with thin-bedded limestone, 550 m thick, with acid pyroclastic rocks increasing westward, over a thousand meters thick.
GeoJSON
Fossils
Type section has Corals Lophophyllum cf. subtilisum, Lithostrotion cf. kueichowense and Lithostrotionella sp. Jijitaizi section contain Fusulinids Pseudostaffella antiqua, Pseudowedekindellina prolixa, Profusulinella longissima, etc.
Age
Depositional setting
It is interpreted as a littoral-neritic facies
Additional Information