Qingtujing Gr
Type Locality and Naming
It was named by Sun Jianchu as the Qingtujing System in 1942. The naming locality is situated at Qingtujing 24 km northwest of Jinchang City, Yongchang region, Gansu Province, with its reference section being located at Qingshuijing (Geological Bureau of Gansu Province, 1968).
Synonym: （青土井群）
Lithology and Thickness
Lower part represents an alternating layer of grey and grey-green shales together with sandstones and micro-conglomerates, intercalated with a small amount of carbonaceous shales, with a thickness of 295 m. Upper part represents purple siltstones and argillaceous siltstones, intercalated with purple mudstones, grey-green mudstones, siltstones and orange conglomerates, with a thickness of 549 m.
Relationships and Distribution
Lower contact
It is unconformably overlying the Paleozoic metamorphic rocks (?). In the area of the Jijigou Gully the group overlies unconformably the Jijigou Gr.
Upper contact
Unconformably underlying the Paleogene or Neogene rocks. Regionally, the next younger unit is central Gansu is the Maliangou Fm of upper Cretaceous.
Regional extent
The formation is distributed in the areas of Qingtujing, Shangjingzi, Jijigou, Tanjinggou of the Chaoshui Basin. The lithology of the lower part of the formation is more or less consistent, yet the lithology of its upper part is changeable greatly, as is shown by the occurrence of conglomerate and sandy conglomerate intercalated with sandstone in it in the areas of Shangjingzi and Tanjinggou Gully.
GeoJSON
Fossils
Its lower part yields plant fossils such as Coniopteris hymenophylloides, C. tatungensis; bivalve fossils as represented by Ferganoconcha subcentralis, F. jorekensis, Sibireconcha glovae.
Age
Depositional setting
Additional Information