Niuwu Fm

Southernmost Anhui. The Niuwu Fm was named by Anhui Bureau of Metallurgy and Geology in 1971. The typical section is situated in Niuwu village in Qimen County, Anhui Province. It is the uppermost formation of the Shangxi Gr.

Synonym: （牛屋组）

The Niuwu Fm is composed of metamorphosed fine clastic rocks. The Niuwu Formation is subdivided into three lithological members. Lower member is composed of low-grade metamorphic sandy siltstone, lithic feldspathic quartzose sandstone interbedded with silty slate and sandy phyllite, locally bearing conglomerate. Middle member is gray and greenish gray phyllitic siltstone intercalated with sandy phyllite and silty phyllite, and with minor lithic arkose in its lower part. Upper member consists of dark gray to black gray sandy, silty phyllite, phyllite interbedded with phyllitic sandy siltstone. In the typical section, the lower part consists of rhythmic interbedding of grey-black low-grade metamorphosed sandy siltstone, feldspar quartz sandstone and silty slate, sandy phyllite, sandwiched with several conglomerate beds, and is 1341 m thick; the middle part is composed of grey, grey-green phyllitic sandy siltstone, silty phyllite, with base intercalated with pebbly arkosic sandstone, and is 874 m thick; and the upper part is a rhythmic interbedding of dark-grey, grey-black silty phyllite, phyllite and silty sandstone, 494 m thick. It ranges from 874 m to 1341 m thick. In some areas, the deposit is about 2710 m thick.

The upper part yields microplants, dominated by Protosphaeridium sp., Lignum cf. punctulosum, L. cf. striatum, Taeniatum crassum, Laminarites sp.

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