Leijiaba Fm
Type Locality and Naming
The type section is located between Zhujiaba and Guanshang, 46 km south of Lixian County, Gansu Province. It was named by Xi’an Institute of Geology and Mineral Resources in 1971; Qin Feng and Gan Yiyan published it formally in 1976.
Lithology and Thickness
Slate. The Lower part is dominated by gray to dark-gray sandy slate (phyllite), intercalated with medium-bedded quartz sandstone, calcareous sandstone and minor sandy limestone.
The Upper part, 2402 m thick, is composed of dark-gray, gray slate (phyllite), calcareous slate intercalated with thin- to medium-bedded bioclastic limestone, lime lenticle and minor thin-platy siltstone.
Relationships and Distribution
Lower contact
Its base is an overthrust fault contact onto the Guanting Group of the Triassic in the south, where the outcropped thickness is more than 1623 m.
Upper contact
It conformably underlies the Yuchiba Fm.
Regional extent
GeoJSON
Fossils
In the limestone it yields abundant corals: Temnophyllum poshiense, Pseudomicroplasma uralica, Parasociophyllum isactis, and brachiopods: Uncinulus parallelepipedus, Athyrisina etc.
In the lower part (Li Yongjun, 1989) the spore: Apiculiretusispora plicata, Acanthotriletes tenuispinosus, Craspedispora arctica, Archaeozonotriletes variabilis etc., have been reported, which can be correlated to those of the Dangduo Fm in Têwo area of West Qinling.
Age
Depositional setting
Additional Information