Luofu Fm
Type Locality and Naming
The type section is along No. 0.12 country road (107° 25'E, 24° 58'N) located east of Luofu Township in Nandan County, Guangxi. It was named by Fifth Prospecting Team of Geological Ministry in 1961. Formerly upper part of a generalized (and no longer used) Chehe Fm – see note for that entry.
[Figure Simplified geological map showing the type locality of Luofu Formation]
Lithology and Thickness
Mudstone. It is dominated by grayish-black and black mudstone, with its surface becoming yellowish-brown after weathering. Siltstone, calcareous and carbonaceous mudstone interbeds are seen. Few lenses of clayey limestone occurs in the upper part and fine sandstone beds with slumping structure in the lower part. Abundant tentaculite and ammonoid fossils are common. It is 200-400 m thick.
[Figure - Outcrops of Luofu Formation in the type locality showing the black mudstone (upper) intercalated with sandstone (lower), length of hammer 2.6 cm.]
Relationships and Distribution
Lower contact
Based on the appearance of sandstone, it is conformably separated from the underlying Tangding Fm (shown as Pingen Fm on some charts) by a 1-m-thick bed of sandstone. Overlies Tanhe Fm in Nanning area.
Upper contact
The upper contact with the overlying Liujiang Formation is sharp, separated by the occurrence of siliceous rocks.
Regional extent
It is restrictively distributed in Nandan-Hechi area, and some localities of Wuxu, Nanning and Shanglin, Guangxi.
GeoJSON
Fossils
It contains abundant tentaculites: Nowakia otomari, Veristellina minuta, and Styliolina sp..
Age
Depositional setting
It is interpreted as an intraplatformal basin with a quiet water environment..
Additional Information