Guyang Fm
Type Locality and Naming
The No.201 Geological Team of the North China Bureau of Geology and Mineral Resources erected the Guyang Coal Measures in 1957. The section for the designation is at Guyang of Inner Mongolia. The reference section is in Xiliannaobao of the Guyang County (109°59′50″E; 41°0′21″N).
Lithology and Thickness
Lower part of the formation is represented by dark purple and yellow brown conglomerate, sandy conglomerate and sandstone with mudstone, while the Middle and Upper parts are gray black mudstone and shale interbedded with yellow gray and gray green sandstone and siltstone, with gypsum and mineable coal beds. It is excess 453 m thick.
Relationships and Distribution
Lower contact
Its base is not observed. Generally the present formation lies conformably or unconformably on the Lisangou Fm or unconformably on the Pre-Cambrian gneiss
Upper contact
Its top is made up of yellow green interbedded sandstone and shale and lies unconformably under the overlying Pleistocene conglomerate.
Regional extent
The present formation mainly occurs in the intramontane basins of the Yinshan Mountains, for example, the Dagutu, Guyang, Kunduitan, Wuchuan and Qixia basins of the Inner Mongolia. It is most developed in the Guyang basin and does not vary greatly in lithology therein. In the Dagetu area, it is dominated by macroclastic sediments including sandstone, conglomerate and sandy conglomerate. In the area north of Huheqin in the northwest of Dersenuor, it is lithologically represented by dark gray and gray white mudstone, silty mudstone and siltstone with conglomerate, gravel-bearing sandstone and marl as well as thin coal seams, with a thickness of 2600 m. In the Yushugou area the upper part of the formation is built up by gray green and yellow green conglomerate with arkose, while the lower part gray green and brown yellow arkose with conglomerate, locally with brown red clayey siltstone, marl and coal streaks, measuring 957.8 m in thickness and being predominantly of piedmont diluvial facies. Besides on the eastern side of the Langshan Mountain there appear basalt partings in the lower part of the formation.
GeoJSON
Fossils
The formation yields estherias Eosestheria sp. , Neimengguestheria gongyomingensis, bivalves Sphaerium jeholense, Pisces Kunyangichtys microdus, Kuntulunia logipterus, floras Tsuga taxoides, Cryptomeria fotanei, Sequoia gracilic, Sabinites neimongolica, Onychiopsis ovata, O. psilotoides, ostracods Cypridea sp. and insects, sporopollen grains etc. [Shown on China Lexicon strat chart as Huaterivian.]
Age
Depositional setting
Additional Information