The Middle Ordovician high - quality Mn ore deposit develops in the five synsedimentary fault depressions in the central Hunan Province, whose environment is of subabyssal, anoxic and insufficient compensation.

• 湘中中奥陶世优质锰矿沉积于桃江成锰沉积盆地的五条同沉积断陷槽内,为次深海缺氧欠补偿沉积环境。