Tanzhuang Fm
Type Locality and Naming
The type section is located at Tanzhuang in Jiyuan City, Henan. It was named by Petroleum Geology Team of Henan Geological Bureau in 1960, and firstly published by Henan Bureau of Geology in 1965. It was equivalent to the uppermost strata of Yanchang Group. The Tanzhuang Formation in Henan Geological Bureau in the geological map specification in 1965 (1:200000 Luoyang) also includes the overlying Lower Anyao Formation of Lower Jurassic.
Synonym:
Lithology and Thickness
This formation, 773.2 m thick, is mainly composed of grayish-yellow, beige yellow and yellowish-green calcareous mudstone interbedded with yellowish-gray, brownish-gray calcareous siltstone, which can be divided into two parts. Lower part is intercalated with medium-fine feldspar quartz sandstone, calcareous fine sandstone, grayish-black mudstone and coal seams. Upper part contains multiple coal seams and oil shale. There is a bed of light gray claystone at the top.
Relationships and Distribution
Lower contact
The Tanzhuang Fm is conformable in contact to underlying Chunshuyao Fm
Upper contact
It is disconformable in contact to overlying Yima Fm of lower-middle Jurassic.
Regional extent
The formation is mainly distributed at Youfangzhuang, Chunshuyao, Tanzhuang of Jiyuan City and Mianchi of Yima in Henan. The thickness becomes thin and lithology coarsen from east to west.
GeoJSON
Fossils
Plants: Danaeopsis fecunda, Bernoullia zeilleri, Todites shensiensis, Cladophlebis gracilis, Cl. raciborskii, Thinnfeldia nordenskioldi; Bivalves: Shaanxiconcha nanzhaoensis, Sh. Mianchiensis, Sh. elliptica.
Age
Depositional setting
It is interpreted as freshwater lacustrine swamp facies.
Additional Information