volcanic block

The Bed G bauxite of Shanxi massif,a paleoresiduum bauxite underlying Bangou Formation of Upper Carboniferous,occurs on the fossil erosion surface of Middle Ordovician of Upper Cambrian.

山西地块的G层铝土矿即产于该地块中奥陶统或上寒武统古侵蚀面之上 ,上石炭统半沟组之下的古风化壳型铝土矿。