Nandaling Fm
Type Locality and Naming
It was named by the Geological College of Beijing in 1961. The naming locality is situated at the Nandaling Ridge in the Mentougou District, Beijing City, with its reference section being located in the area of Guanting Village-Yangpoyuan Village, Mentougou District, Beijing City (Geological College of Beijing, 1961, geological map on the scale 1:50000, Shijingshan Sheet, Summary Report on the Regional Geological Survey in the Territory of the Liangxiang Sheet).
Synonym: （南大岭组）
Lithology and Thickness
Composed of dark-green, grey-green and black-grey compacted massive basalt, andesite, vesicular and amygdaloidal basalts, andesite, andesitic agglomerates, andesitic breccias and andesitic lithic tuffs, intercalated with yellow-green and yellow-brown sandstones, conglomerates, dark-green silty mudstones and black-grey shales, with a thickness of 15-767 m.
Relationships and Distribution
Lower contact
In the naming section the formation is in a disconformable contact with the underlying Xingshikou Fm. While in the area north of the Wujiachang Village of Changde City, northern Hebei the formation is in a conformable contact with the underlying Xingshikou Fm
Upper contact
It is in a disconformable contact with the overlying Yaopo Fm. While in the area north of the Wujiachang Village of Changde City, northern Hebei the formation is in a conformable contact with the overlying Huayuan Fm
Regional extent
The formation is distributed extensively and is exposed on the surface in the areas of Badachu, Nandaling, Datai and Da’an Mt in the western part of Beijing City, as well as in the areas of Xiabancheng, Wujiachang, Wangyingzi and Dashipeng of the Luanping-Chengde region and in the Xiahuayuan area of Xuanhua region. Both the thickness and lithology of the formation are changeable from region to region, with the thickness getting smaller westerly, being of over 767 m at Badachu; of 547 m in the area of Guanting-Yangpoyuan; of 362 m at Datai; and being of only 15 m in the area of Baoershi. In the area of West Hills of Beijing the formation is characterized by the predominance of intermediate volcaniclastic rocks, associated occasionally with intermediate lavas, while in the Xiahuayuan area of northwestern Hebei it is characterized by the predominance of purple and grey-green andesites, intercalated with poststones (= fine-grained sandstone), shales and tuffs.
GeoJSON
Fossils
No reliable fossils have so far been found in the formation.
Age
Depositional setting
Additional Information