That a: The Mn-deposits of MiddleOrdovicianEpoch in central Hunan were high grade Mn-ores with low-P, low-Fe and high basicity;
提出：①湘中地区中奥陶世锰矿是低磷、低铁、高碱度优质锰矿石；
2
Comprehensive researches have concluded that the Heishan ophiolite was formed in Nanhua Ordovician period and its structural location in Silurian period early Middle Devonian epoch.