Elitu Fm
(12), Kungurian Stage (uppermost Cisuralian Epoch) through Guadalupian Epoch [latest-Early through Middle Permian]
Type Locality and Naming
The type section is located at Elitu Grazing Land, Zhengxiang-Baiqi, Inner Mongolia. It was named by the 1st Regional Geological Survey Party of Inner Mongolia in 1976.
Lithology and Thickness
Clastics and intermediate volcanic rocks. Lower part consists of interbeds of yellow-brown and purple coarse- to fine-grained sandstones and pebble-bearing lithoclastic and crystal-clastic tuffs. Middle part is interbeds of grey black and yellow-green siltstone and shale, pebble-bearing coarse-grained sandstone and bedded limestone. Upper part is grey and grey-green tuffaceous shale, sandstone and bedded tuffaceous breccia, intercalated with andesitic porphyrite and brecciated andesite. Thickness is over 1668 m in the area to the south of West Mulun River and to the west of Balin Bridge where it has clear lower/upper contacts.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Qingfengshan Fm in the area to the south of West Mulun River and to the west of Balin Bridge; but type section lacks clear contact. Next older unit in Permian Lexicon chart for this region is the Sanmianjing Fm.
Upper contact
Conformable contact with the overlying Yujiabeigou Fm in the area to the south of West Mulun River and to the west of Balin Bridge; but type section lacks clear contact.
Regional extent
Distributed in the Elitu Grazing Land; the Saili Trench of Huade County, Zhenglanqi and Baokang areas of Hebei Province. In the area of Zhaoyang River the volcaniclastic rocks are increasing in amount and with the tuffs yielding phytolite such as Paracalamites, etc. In the Xiaojingzi and Shuangjingzi areas the formation is intercalated with marine strata, with the marl yielding brachiopods as represented by Cancrinella.
GeoJSON
Fossils
Estheria fossils represented by Concherisma and Glyptoasmussia. Plant fossils (phytolites) such as Pecopteris tenuicostata, Sphenopteris grabaui, Odontopteris chui, Taeniopteris norinii, Annularia gracilescens, Gigantonoclea, etc.,
Age
Depositional setting
It is interpreted as continental-margin back-arc littoral-basin deposits.
Additional Information