Geological characteristics and ore indicators of lead-zinc deposits in northwestern Hunan,China

Lead-zinc deposits in northwestern Hunan are famous stratabound metal deposits in China and their geological characteristics and sizes are similar to Mississippi Valley lead-zinc deposits in the United States.Northwestern Hunan is located in two second-order tectonic units—the Upper Yangtze block and Jiangnan block(northwestern margin).According to the tectonic setting and geological-geochemical characteristics,the lead-zinc deposits in northwestern Hunan may be classified into the Luota,Huayuan and Baojing lead-zinc field and Fenghuang lead-zinc-mercury field.In these ore fields there are three ore-controlling horizons:algal limestone in the Lower Member of the Lower Cambrian Qingxudong Formation,dolomicrite in the Upper Member of the Middle Cambrian Aoxi Formation and bioclastic limestone of the Lower Ordovician Nanjinguan Formation.The paper completely deals with the geological characteristics of lead-zinc deposits in northwestern Hunan and discusses their ore indicators.