Hongshuichuan Gr
Type Locality and Naming
The type section is located at Naocangjiangou, Maduo County, Qinghai Province and the mouth of Tatuo coal mine, Dulan County. The reference section is located in Haotelowa, the upper reaches of Nuomuhong River, Dulan County. It was named by the first regional survey team of Qinghai Geological Bureau in 1970. In 1982, Xu Xian et al publicly cited this group for the first time and divided it into two rock groups, namely the upper sandstone limestone group and the lower glutenite-volcanic rock group. In 1987, Rao Rongbiao and others named it the Upper Rock Formation and Lower Rock Formation
Synonym:
Lithology and Thickness
It is composed of clastic rock, volcanic clastic rock and limestone. Lower rock group is composed of purple-red, gray-purple, gray-green sandstone and glutenite (=gravel), and contains a lot of volcanic clastic rocks. The bottom is a thick conglomerate. Total thickness of 680-968 m. Upper rock group is composed of clastic limestone, marl, Breccia limestone is dominated by sand slate. The thickness is generally 500-900 m.
Relationships and Distribution
Lower contact
The bottom is marked by the initial appearance of thick conglomerate, which is false conformable contact with the underlying Lower Permian Maokou Fm (at type region). Regionally, the next older unit is an "unnamed conglomerate" of upper Permian, which is above the Maerzheng Fm (Ma'erzhengFm).
Upper contact
The top is conformable contact with the overlying Naocangjiangou Fm
Regional extent
This group is mainly exposed in Dulan County and northern Maduo County in Qinghai Province. The lithology and thickness vary greatly. The lower part to the north of Soto Lake is dominated by sandstone with acid tuff lava, 1218-1971 m thick, and the upper part also contains volcanic rocks and pyroclastic rocks; Arak Lake, Sanchakou, Kekeke Tewei See the volcanic rock with a thickness of 176-1456 m.
GeoJSON
Fossils
Ammonoids: Anasabirites kingianus, Anakashmirites oyensi, Zeoites helenae, Pseudocelitites sp., Pseudosageceras sp., Prosphingites sp., Arnautocelites sp., Subcolumbites sp., Subvishnuites sp., and Bivalves: Claraia sp., C. concentrica, Entolum buscites microtis, Eumorphotis multiformis hongshuichuanensis, E. huancangensis.
Age
Depositional setting
It is interpreted as marine volcanic eruption-sedimentary products.
Additional Information