Jiaokeng Fm

This formation was named by 301 Geological Team of Fujian Geological Bureau from 1959 to 1963. It was first publicly quoted by Fujian Metallurgical Industry Bureau in 1972. The named section is located in both sides of Futun Stream in Jiaokeng Coal Mine Area, Shaowu County, Fujian Province. The Mesozoic strata in northern Fujian are collectively called the "Lishan Coal Measures" by Wang Hengsheng et al. (1930), with the age of Jurassic. Wang Shaowen (1930) called the formation "Guiling Sandstone" and "Tongziyan Coal System". Cheng Yuqi et al. (1936) called it "Pantian System", and Nan Yanzong et al. (1941) called it "Mangtang Sand Shale System". At the end of the 1950s, Fujian Geological Bureau called it "Lishan Group", with the era of Jurassic. The 301 Geological Team of Fujian (1959 ~ 1963) divided the Lishan Gr into the upper Gexian Fm (now known as Lishan Fm) and the lower Jiaokeng Fm, which was dated as Jurassic.

Synonym:

The lithology of the lower member is complex. Lower part of the Lower member is dominated by conglomerate and sandstone of piedmont facies, interbedded with pyroclastic rocks. The upper part of the lower member is siltstone of lacustrine siltstone and carbonaceous mudstone and coal seam of peat swamp facies. Upper member is composed of lacustrine siltstone, fine sandstone, medium to coarse-grained pebbled sandstone and a little schist. The thickness is 954 m, and the thickness of the Jiaokeng Formation is over 1000 m.

Plants: Anthrophyopsis sp., Goeppertella sp., Cycadocarpidium erdmanni, Pterophyllum ptilum et al.; There are conchostracans and bivalves.

It is interpreted as a piedmont or peat swamp facies.