Laowuopu Fm

The type section is located at Laowuopu of the Shiguai Region, Baotou City, Inner Mongolia (110°30′, 40°40′). It was named by Gu Zhiwei in 1955, and was cited officially in the "Regional Stratigraphic Chart of North China Region: Fascicle of Inner Mongolia" 1978).

Clastics. Composed of interbeds of dark-purple pebble-bearing coarse-grained sandstone, siltstone together with medium- and fine-grained sandstones, intercalated with feldspar-rich sandstone and calcareous-nodule layer, with its basal part representing rock layers intercalated with dark-purple shale lenses. Lower part of the formation is composed of brown-purple and dark-grey feldspar-rich sandstones with a remarkable cross stratification, intercalated with shale lenses. Middle part of the formation consists of dark-purple and purplish red siltstones, intercalated with interbeds of greywacke, with its top being composed of a layer of calcareous slate. Upper part of the formation is composed of purple medium- and thick-bedded pebble-bearing feldspar-coarse-grained sandstone. The thickness is over 729 m.

No fossils have been found

It is interpreted as intermontane-basin deposits.