The zonation and genetic mechanism of Zunyi high-and low-ferrous bauxites

Abstract：Early Carbonaceous sedimentary bauxite and its aluminum-bearing rock series in the Zunyi bauxite belt have totally undergone sedimentation-accumulation on the slightly southward inclined plantation formed during the late Devonian and Early Carbonaceous Ziyun movement, and the high- and low-ferrous bauxites apparently assume zonation. Original materials of bauxites and the ore-bearing rock series consist dominantly of gibbsite laterite crust formed by illite shale of the Lower Ordovician Meitan Formation. The zonation of bauxite is related to the material-transport distance of the laterite crust, i.e., the high-ferrous bauxites occur in nearby and high places, and the low-ferrous bauxites appear in distant and low places. Generally speaking, the transport distance is relatively short? and the bauxites were formed by the near-source transport, sedimentation and accumulation.