Yueshan Fm
Type Locality and Naming
Anhui Geological Bureau 326 Geological Team named in 1966. The named section is located in Huaining Yueshan, Anhui Province.
Synonym:
Lithology and Thickness
It is mainly grey-white, grey-green siltstone, silty shale, interbedded with gray dolomitic limestone and its lens or interbedding. Its thickness is generally 33 to 34 m, but the thickness can be up to 200 m.
Relationships and Distribution
Lower contact
Concordant contact between the bluish grey dolomitic limestone at the bottom and the salt soluble breccia at the top of the underlying East Ma'anshan Fm (= Dongma'anshan Fm).
Upper contact
Concordant contact between the top and the purplish red, bluish grey and greyish green thin to medium thick siltstone at the bottom of the overlying Tongtoujian Fm. Mainly it is an upward color change in the siltstone from greenish-grey to purplish-pink.
Regional extent
The formation is restrictively distributed in Wuhu and Anqing.
GeoJSON
Fossils
Plants: Neocalamites sp.; Bivalves: Costatoria submultistriata, Asoella illyrica.
Age
Depositional setting
Additional Information
The lithology of the [original] named Yueshan Fm can be divided into upper and lower members: the lower member is limestone. The upper member of the dolomite. The Yueshan Fm is between the purplish red, bluish grey and greyish green siltstone of the Tongtoujian Fm of the Middle and Upper Triassic and the limestone of the Nanlinghu Fm of the Lower Triassic, and the age is the Middle Triassic. In 1979, according to the differences in lithology, lithofacies and biota, Wang Guixiang renamed the lower [limestone] member as the Dongmaanshan Fm, so the current Yueshan Fm is only equivalent to the upper [dolomitic] member of the original meaning (i. e. dolomite member). Anhui Geological Bureau 326 Team (1966), East China Institute of Geology, Anhui District Survey Team originally identified the Yueshan Fm as the Late Triassic. Now interpreted as middle-Middle Triassic.