Jiujialu Formation, Dafang County, Bijie, Guizhou, Chinai

Regional Level Types
Jiujialu Formation	Formation
Dafang County	County
Bijie	Prefecture
Guizhou	Province
China	Country

The Jiujialu Formation is typically composed of three units, ranging in thickness from 0 to 30 m. The underlying strata display a noticeable discordant contact, primarily consisting of ancient karst unconformities. The Jiujialu Formation can be divided into three layers: upper, middle, and lower. The upper unit contains coal layers, claystone, and carbonaceous shale; the middle unit consists of claystone and bauxite; and the lower unit is rich in iron, containing ferruginous clays and limonite. The Jiujialu Formation is extensively exposed in central Guizhou Province, and its distribution and thickness are influenced by the negative topography of the early Carboniferous paleo–karst. The underlying strata transition from south to north, changing from dolomite of the Qingxudong Formation (Cam1q) and Loushanguan Group (Cam2–3ls) in Nayong, Dongdi, Qianxi, Bumiao, and the south of Qingzhen, Weicheng, to Loushanguan Group (Cam2–3ls) dolomite in Nayong, Dongdi, Qianxi, Bumiao, Qingzhen, Weicheng, and Tongzi Formation (O1t) middle and upper Ordovician (O2+3) limestone interbedded shale layer in Bijie, Jinsha, Zunyi, Shangji, Weng'an, and Yuhe, and finally to Hanjiadian Group (S1hn) siltstone, muddy shale, or limestone lens in Renhuai, Maoba, Zunyi, Gaoping, Meitan, Gaotai, Yuqing, Taiping.
Four sections of the Lower Carboniferous Jiujialu Formation (C1jj) in central Guizhou Province, South China. The results show that detrital materials in the argillaceous dolomite with an average lithium content of approximately 46.17 ppm are primarily composed of quartz, muscovite, and microcline. Lithium–rich claystones in the lower Carboniferous Jiujialu Formation in central Guizhou Province are restricted to a paleo-uplift underlain by argillaceous carbonate bedrock, which is mainly argillaceous dolomite of the Loushanguan Group. The sampling sites are located in Datian near Jinsha, Changgou-1 and Changgou-2 near Xifeng, and Saping near Xiuwen, located near the core area of the Central Guizhou Uplift.
The Li–rich clays occur within the lower Carboniferous Jiujialu Formation. The clay mineral content in the Jiujialu Formation ranges from 50 % to 100 %, and mainly includes illite, chlorite, smectite, kaolinite, and mixed-layer illite–smectite. The thickness of the Jiujialu Formation is controlled by the karst topography. Generally, it is thicker in deeper karst depressions and thinner on higher terrains. The Jiujialu Formation typically comprises three units with thicknesses of 5–20 m. the upper unit contains coal layers, claystone, and black carbonaceous shale; the middle unit consists of claystone and bauxite; and the lower unit is Fe–rich layer and the lithology is ferruginous clays and contains limonite , among these three units, the upper unit is generally thin and often missing.

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References