Dafenggou Fm
Type Locality and Naming
The type section is located at Dafenggou of Luohe Township in Xunyang County, Shaanxi Province. It was named by No 1 Shaanxi Geological Team in 1964 and Du Dinghan et al. formally quoted it in 1986.
Lithology and Thickness
Sandstone, limestone. Lower part is purplish-red to grayish-black iron-bearing quartz sandstone intercalated with sandy phyllite, 130.3 m thick. The sandstone displays tabular, wedge-shaped and bi-directional cross-bedding, sand-laminated bedding, ripple marks.
Upper part is grayish-white massive dolomitic limestone, gray medium- to thick-bedded bioclastic limestone, 57.7 m thick.
Relationships and Distribution
Lower contact
Conformably overlies the Shijiagou Fm.
Upper contact
Conformably overlain by the Yanglinggou Fm.
Regional extent
The formation is distributed in the area of Xunyang, Fengxian, Shanyang County, where it is relatively uniform with a thickness of 112 to 188 m. Westward in the Wafangba area in Fengxian County, carbonate rock increases remarkably in thickness to 609 m but decreases to 278 m in Songshuping of Shanyang County.
GeoJSON
Fossils
The formation yields brachiopods Stringocephalus, Atrypa; coral Charactophyllum.
In Songshuping of Shanyang County coral of Disphyllum and brachiopod of Spinatrypa bodini have been found. They indicate an early Late Devonian age.
Age
Depositional setting
It is interpreted as a beach to subtidal deposits.
Additional Information