湘西北下光荣矿区铅锌矿床主要地球化学特征

湘西北洛塔矿田下光荣矿区中的铅锌矿床主要赋存于下奥陶统的南津关组、分乡组及红花园组中,层控特征明显。矿床地球化学特征分析表明矿质主要来自造山带,硫质主要来源于同沉积的海水硫酸盐。大气降水等组成的含矿热卤水在地下流动的过程中,不断萃取地层中的金属成份,并在温度降低的同时,沉淀富集金属物质成份,有用组份主要以氯的络合物方式进行搬运,主成矿期的成矿温度为108～197℃,矿床成因类型属层控型低温热液矿床。加里东期和燕山期的改造则决定了矿床的现今分布格局和矿体的赋存状态及产状。

Main geochemical characteristics of lead-zinc eposits in Xiaguangrong ore district,northwestern Hunan

The lead-zinc deposits in Xiaguangrong ore district of Luota Ore Field,northwestern Hunan,occurred in the Nanjinguan,Fengxiang and Honghuayuan Formations in age of Early Ordovician,with an obvious feature of stratabound ore deposit.Based on field survey and measurements of Pb,O and S isotopes,the ore-bearing formation and later reformation were discussd in the paper.The geochemical characteristics of the lead-zinc deposits revealed that the metal originated from intracontinent collision orogen,and the sulphide substance sourced from syndeposited seawater sulphates mainly.The mineralization was formed by the circulation of hot brine,which came from meteoric water and absorded the metal substance from the surrounding strata in its flowing process.The main mineralization constituent was transited in a form of chlorine complex;and the temperature in main mineralization period was 108～197℃.The genetic type of the lead-zinc deposit was strata-bound ore deposit with low temperature and hot fluid in this area.The reformation in the Caledonian and Yanshanian played an important role in distributional framework of ore deposits and the shapes and occurrences of ore bodies.