Miaoshanhu Fm
Type Locality and Naming
The Miaoshanhu Formation was erected by the No.108 Geological Team under the Yinchuan Bureau of Petroleum Exploration in 1969. The type locality for the designation is in Miaoshanhu of Ningxia. The reference section is at Yingfagou of the Qingtongxia City of Ningxia (105°46′E; 37°52′N).
Lithology and Thickness
Lower part of the Miaoshanhu Formation is built up by brown red and break red conglomerate and sandstone. Upper part is variegated (loose, brick red, gray green and gray white) sandstone, siltstone and mudstone (clay) with grayish white marl, cryptocrystalline limestone and sandy conglomerate lenses. The formation is 938.4 m thick.
Relationships and Distribution
Lower contact
The base of the formation marked by loose sandstone interbedded with mudstone lies unconformably on the Qingshuiying Fm [NOTE: According to Paleogene set of Ningxia formations, the Qingshuiying Fm is Oligocene => can't be a "lower" contact (unless fault) => maybe error in this Miaochanhu Fm entry?]
Upper contact
Regional extent
The present formation mainly occurs in the Qingtongxia City and the Miaoshanhu area at the southeast foot of the Helan Mountain of Ningxia. On the section measured at Hongyazi of the Qingtongxia City, it becomes finer in lithology. The lower part of the formation is built up by brown red conglomerate and sandstone with mudstone, while the upper part purple red and tangerine mudstone and siltstone with marl, measuring more than 504.2 m in thickness.
GeoJSON
Fossils
The formation yields ostracods Cypridea (Cyamocypris) sp., C. (Morinina) cf. depressa; bivalve Sphaerium sp., and also ostracods Cypridea acclina.
Age
Depositional setting
It is marked by fluvial-lacustrine deposition.
Additional Information