Boluo Gr
Type Locality and Naming
It was named as the “Boluo Conglomerate Layer” by Meng Zhaoyi in 1946, and was first cited publicly in the [Regional Stratigraphic Charts of China (draft)] in 1956. The naming locality is situated in the Boluohutong area 18 km southeast of Yumen City, Gansu Province.
Synonym:
Lithology and Thickness
It is composed essentially of purple pebblestone, cobblestone, micro-conglomerate, fine-grained sandstone and siltstone, with its lower part being intercalated with grey-green fine-grained sandstone. Its thickness is of more than 234 m.
Relationships and Distribution
Lower contact
The basal part of the particular group marked by a layer of purple pebblestone and cobblestone is in a disconformable contact with the underlying strata consisting of yellow-green pebble-bearing fine-grained sandstone and siltstone (temporarily put as Shanhujing Gr of Late Triassic; pending clarification if there is Lower Jurassic in this region).
Upper contact
No top part of the group has been found. Schematic strat column suggests next younger regional unit is the Chijinqiao Fm of mid-Early Cret.
Regional extent
The particular group is distributed in the areas of Hexi Corridor, western Qilian Mts and Beishan Mts of Gansu Province. The lithology of the group in various places is consistent, yet its thickness varies more or less greatly in a range from 443 m to 1197 m.
GeoJSON
Fossils
The basal part of it yielding plant fossils as represented by Neocalamites sp. as well as spore and pollen fossils.
Age
Depositional setting
Additional Information