Xiayao Fm
Type Locality and Naming
The type section is located in the Xiayao area of Huangshi City, Hubei Province.It was named by Wang Shaowei et al., in 1966.
Lithology and Thickness
Limestone. Its lower part represents a suite of light-grey to dark-grey medium-bedded and thick-bedded cherty concretion-bearing limestones. Only a local segment has thin-bedded siliceous rocks, or with the dolomite occurring in its upper part. Variable thickness; with range from about 5 to 200 m.
Relationships and Distribution
Lower contact
Conformable contact with the Longtan Fm
Upper contact
Conformable contact with the Dalong Fm
Regional extent
Although its thickness is not so great, yet the formation is stable in its distribution in the Yangtze stratigraphic region. Its thickness is of 10-30 m in the southeastern part of Hubei Province, and is getting smaller in a direction from south to north. In the West Hubei-Southwest Hubei, its thickness is commonly of about 15-58 m, locally (for instance, in the area of Jinjia’ao of Changyang County) being of over 200 m. In the area to the east of the Ziqiu Country of Changyang County to Songzi City the formation has facially changed into siliceous rocks of the Dalong Fm. In the Jingshan-Nanzhang area it is only 4-7 m thick and is thinning out in the area extending from the northwestern part of the Nanzhang County to Baokang County. In the area of south Anhui to south Jiangsu provinces, the formation is commonly regarded as the Top Limestone Member of the Longtan Fm, known locally as the Coal-pressing Limestone, with a thickness of less than 10 m.
GeoJSON
Fossils
In the area of south Anhui to south Jiangsu provinces, it yields abundant Brachiopod fossils such as Neophricodothyris waageni, N. asiatica, Squamularia calori, Dictyoclostus margritatus, Spinomaginifera kueichowensis, Tyloplecta yangtzeensis, Edristeges kayseri, Cathaysia chonetoides, Leptodus nobilis, etc.; Fusulinids such as Codonofusiella schubertelloides, C. paradoxical, C. lui, Palaeofusulina parafusiformis, P. nana, P. fluxa, Reichelina simplex, etc.; and Corals such as Waagenophyllum simplex, Tachylasma lopingense, etc.
Age
Depositional setting
Additional Information