Tangshan Fm
Type Locality and Naming
The type section lies at the west slope of Tangshan Mt. northeast of Tangshan City, Kaiping coalfield, Hebei. It was named by Grabau in 1920.
Lithology and Thickness
Fe-rich Claystone, Sandstone, and Coal. Dominated by mudstone, intercalated with siltstone and fine-grained sandstone. There are three intercalations of thin- to moderately thick-bedded limestone, formerly called K1, K2 and K3 in ascending order. The bottom is formed by ferroaluminous mudstone and the Shanxi-type iron ore. Below K1 are gray, gray-purple and yellow ferroaluminous mudstones, intercalated with yellow thin-bedded fine-grained sandstone, occasionally with 3 coal seams (Coal 19, Coal 20 and Coal 21). Between K1−K2, it is dominated by gray thin-bedded mudstone, intercalated with yellow-gray fine-grained sandstone and thin-bedded ferruginous oolitic sandstone, locally with a coal seam (Coal 18). The interval between K2−K3 is composed of yellow-gray calcareous siltstone and medium-grained sandstone. Thickness 43−113 m.
Relationships and Distribution
Lower contact
Disconformable contact of bottom ferroaluminous mudstone (Layer G) on underlying Mid-Lower Ordovician strata
Upper contact
Conformable contact with the overlying Kaiping Fm
Regional extent
The formation is also distributed in the Xinglong area, Shanhaiguan and Jingxi area of Liaoning, where it is called the Benxi Fm.
GeoJSON
Fossils
Contains Fusulinids Pseudostaffella sphaeroides, Fusulinella bocki and Fusulina konnoi; Brachiopods Choristites mosquensis, C. parlovai, Chonetes granulifer and C. hardyensis; Corals Multithecopora penchiensis, Chaetetes tangshanensi, etc.; Gastropod Euomplalus sp.; Bivalve Acanthopecten sp.; Trilobites Phillipsia cf. gansuensis, etc.; Plants Sphenopteris neuropteroides, Neuropteris kaipingiana, N. cf. gigantea, Linopteris brongniartii, Conchophyllum richthofenii, etc.
Age
Depositional setting
It is interpreted as littoral-neritic deposits.
Additional Information