Etouchang Fm
Type Locality and Naming
East-central Yunnan. The Etouchang Fm was named by the Comprehensive Party of Geology, Yunnan Bureau of Geology in 1966. The reference section is at Xiaoxinchang-Huanglongzhai River, Lufeng County, Yunnan Province.
Synonym: (鹅头厂组)
Lithology and Thickness
The Etouchang Fm is composed of banded interbedding of dark-grey and grey-black siliceous slate with silty slate. The base contains carbonaceous and siliceous dolomite, and the lower part is sandwiched with muddy dolomite, chert, limestone and siliceous slate. The middle part is composed of meta-sandstone. The exposed thickness in Etouchang area is recorded as 816 m, but it is 1266 m in the Yimen Copper ore District, and 1020 m in the Yuanjiang District.
Relationships and Distribution
Lower contact
It is stable in lithological character and in conformable contact with the underlying Luoxue Fm
Upper contact
It is in conformable contact with the overlying Luzhijiang Fm
Regional extent
East-central Yunnan. It is distributed in Lufang, Yuanjiang and Yimen.
GeoJSON
Fossils
The microplants are: Trachysphaeridium etouchangense, T. dalongkouense, Sicyomorpha, Kildinella, Trematosphaeridium, Lignum, Polyporata.
Age
Depositional setting
Additional Information
The carbonaceous slate and dolomite in the lower part of the formation are the copper-bearing horizons, which are up to commercial grade. In Dongchuan ore district the stratigraphic horizon equivalent to the copper-bearing stratigraphic unit is called Heishan Fm, the synonym of the Etouchang Fm, but there is some difference from each other in lithological character.