Lengshuigou Fm
Type Locality and Naming
The type section is located at the “Lengshui Gully section” (E109°12′, N34°21′) of the Beihou village, Lengshuigou town, southwest of Lintong District of Xi’an City, Shaanxi Province (BGMRS(Shaanxi)P, 1998). It was named by Jia et al. (1966).
Lithology and Thickness
It mainly consists of brownish-red sandy mudstones interbedded with greyish-yellow and greyish-green sandstones. Its bottom is formed by conglomerates. It contains fossil mammals. Its thickness is in range of 20~82 m.
Relationships and Distribution
Lower contact
In the type section, the Lengshuigou Fm unconformably contacts with the underlying Eocene Honghe Fm.
Upper contact
In the type section, the Lengshuigou Fm is unconformably overlain by the Upper Miocene Bahe Fm. But regionally, may be below the Koujiacun Fm (see Additional Information for discussion).
Regional extent
In other area, it unconformably contacts with the overlain Koujiacun Fm or Bahe Fm and the underlying Bailuyuan Fm. The thickness of this formation is about 82 m in Weinan, 20 m in Lantian, and 59 m in Lintong, respectively. This formation is mainly distributed to Lantian-Weinan area, Shaanxi Province.
GeoJSON
Fossils
Mammals: Alloptox minor, Tsaganolagus wangi, Gomphotherium shensiensis, Selenolopodon spectabilis, Hispanotherium lingtungensis, Listriodon lishanensis, Palaeotragus sp., Stephanocemas sp., Palaeomeryx sp., ? Micromeryx sp., Turcocerus lishanensis (Zhang et al., 1978; Qiu and Qiu, 1995).
Age
Depositional setting
It is interpreted as river-lake environment.
Additional Information
Regional extent:
In other area, it unconformably contacts with the overlain Koujiacun Fm or Bahe Fm and the underlying Bailuyuan Fm. The thickness of this formation is about 82 m in Weinan, 20 m in Lantian, and 59 m in Lintong, respectively. This formation is mainly distributed to Lantian-Weinan area, Shaanxi Province.
GeoJSON:
Fossils:
Mammals: Alloptox minor, Tsaganolagus wangi, Gomphotherium shensiensis, Selenolopodon spectabilis, Hispanotherium lingtungensis, Listriodon lishanensis, Palaeotragus sp., Stephanocemas sp., Palaeomeryx sp., ? Micromeryx sp., Turcocerus lishanensis (Zhang et al., 1978; Qiu and Qiu, 1995).
Age:
Tao Deng et al. (2019; Neogene integrated stratigraphy and timescale of China) show it as spanning the Burdigalian through Langhian.
Age Span:
Beginning stage: Burdigalian
Fraction up in beginning stage: 0.3
Beginning date (Ma):
Ending stage: Langhian
Fraction up in ending stage: 1.0
Ending date (Ma):
Depositional setting:
It is interpreted as river-lake environment.
Depositional-pattern:
Additional information
The Lengshuigou Fm was considered below the Koujiacun Fm in stratigraphy (Jia et al., 1966; Zhang et al., 1978; Li et al., 1984). However, Qiu and Qiu (1995) considered that the Lengshuigou Fauna from the Lengshuigou Fm is distinct younger than the Koujiacun Fauna from the Koujiacun Fm, and suggested placing the Lengshuigou Fm above the Koujiacun Fm. Future work need to be conducted to confirm the stratigraphic correlation between these two formations.