Maoniushan Fm
Type Locality and Naming
The type section is located at Maoniushan Mt. in Dulan County, Qinghai Province. It was named by Qinghai Bureau of Petroleum in 1958.
Lithology and Thickness
Sandstone, andesitic rocks. The very-thick formation at the Maoniushan section in Duyun, is composed of purple and grayish-green arkose, pebble-bearing sandstone and fine-grained conglomerate; but the Upper part consists of pyroxene andesite, andesitic lava, andesitic breccia, andesitic agglomerate, pebble-bearing andesitic lava and tuff and a few feldspathic greywacke. It is totaling 4992 m in thickness. The lithology of this formation is relatively uniform, but thickness changes considerably from more than 1000 m to more than 5000 m.
Relationships and Distribution
Lower contact
It has unconformable contact with the underlying Tanjianshan Gr of Upper Ordovician.
Upper contact
It has unconformable contact with the overlying Lower Carboniferous. In another region (also column 18 area) is the semi-coeval Devonian Amunik Fm conglomerate-sands
Regional extent
GeoJSON
Fossils
No fossils are found in this section, but in purplish-red feldspathic sandstone at southern side of Saishitengshan Mt. some plant fossils occur: Leptophloeum rhombicum, Sublepidodendron, Lepidodendropsis.
Age
Depositional setting
Additional Information