Yuanjiagou Fm
Type Locality and Naming
The type section is located at Yuanjiagou of the Xicha River, about 20 km northeast of Xunyang, Shaanxi; and the reference section at Sanlixia (about 30 km northwest of Xunyang County Seat) of Xunyang. It was named by Shaanxi Party of Regional Geological Survey in 1966, and formally cited in the Regional Stratigraphic Scale of Southwestern China ⎯ Shaanxi Volume in 1983.
Lithology and Thickness
Limestone. Dominated by neritic carbonate rock deposits, consisting of gray and dark-gray thick-bedded massive clayey limestones intercalated with sandy and calcareous limestones; 174.8 m thick.
Relationships and Distribution
Lower contact
Conformable (? – Strat chart shows a gap) contact with the underlying Devonian Nanyangshan Fm (not in Devonian Lexicon) (or Tieshan Fm?)
Upper contact
Conformable contact with the overlying Sixiakou Fm (and Fanjaiping Fm)
Regional extent
Distributed in the areas of Zhen’an and Xunyang of Shaanxi as well as Yunxi of Hubei, consisting almost completely of limestone around Miliangchuan of Zhen’an, ~200 m thick. Going southward and eastward, it is intercalated with calcareous sandstone and increasing in shale, reaching 975 m in thickness
GeoJSON
Fossils
Corals Caninia cornunconiae var. gigantea, etc.,
Age
Depositional setting
It is interpreted as a neritic carbonate
Additional Information