Lishuwo Fm
Type Locality and Naming
It was named by the Jiangxi Party of Regional Geological Survey in 1963. The type section is at Lishuwo, north of Dianbeicun Village, Chuantan, Wuning County in northwest Jiangxi Province (the Jiangxi Bureau of Geology and Mineral Resources, 1984).
Synonym: (梨树窝组)
Lithology and Thickness
The Lishuwo Fm, 1230 m in thickness, consists of interbeds of black gray siltstone with shale at the base; Lower part of dark gray sandstone intercalated with gray shale; and Middle and Upper parts of yellow green, gray green and gray yellow sandy shale and sandstone.
Relationships and Distribution
Lower contact
It is in continuous sedimentation relation with the underlying Xinkailing Fm (= Xinkailing Bed of lower-half of Hirnantian Stage at the uppermost Wufeng Fm); however, in pseudo-conformity with different horizons of Ordovician strata in the areas of De’an, Hukou and Penze counties because of absence of the shale at the base.
Upper contact
It is in continuous sedimentation relation with the overlying Dianbei Fm.
Regional extent
The formation is exposed in Wuning and Xiushui counties of Jiangxi Province and in Tongshan County of Hubei Province.
GeoJSON
Fossils
The lower part of the formation is rich in graptolites, including the Normalograptus bohemicus zone, the Normalograptus persculptus zone up to the Pristiograptus leei zone (Fang Yiting et al, 1990). The strata corresponded to the lower two graptolite zones are attributed to the latest Ordovician in age. No graptolite is found in the upper part of the Lishuwo Fm, which, however, may include strata correspondent to the Demirastrites triangulatus zone.
Age
Depositional setting
Additional Information