(1. 中南大学 地球科学与信息物理学院 有色金属成矿预测教育部重点实验室，长沙 410083；
2. 江苏省有色金属华东地质勘查局，南京 210007)
摘 要: 为探明大河边重晶石矿床的物质来源，在分析矿床地质的基础上，系统研究矿石矿物的同位素组成、稀土元素及有机地球化学特征。结果表明：样品中δ18OSMOW与δ34SV-CDT呈正比关系，推测氧和硫元素以SO42-的形式参与成矿；δ34SV-CDT值较高表明硫可能来源于热液与海水，高34S值是由热液体系中硫同位素分馏和海洋中还原细菌分馏造成的。矿石和围岩具有相似的高轻重稀土元素比、负铈异常及正铕异常等特征，表明它们都为热水沉积产物。生物标志物指标表明：有机质主要源自于海相低等菌藻类浮游生物。综合成矿背景和锶同位素特征研究，推测钡主要来源于热水沉积作用。综合同位素、稀土元素和有机地球化学研究认为，大河边重晶石矿床的成矿物质主要来源于海水和热水沉积作用，地壳和地幔均提供物质来源，且海洋生物参与成矿。
关键字: 物质来源；大河边重晶石矿床；同位素；稀土元素
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. East China Mineral Exploration and Development Bureau for Non-Ferrous Metals, Nanjing 210007, China）
Abstract:Based on the research of geological characteristics of the Dahebian deposit, the compositions of S, O, Sr isotopes, rare earth elements and organic geochemistry were systematically studied to discuss the material sources of the Dahebian barite deposit. The positive correlation between δ18OSMOW and δ34SV-CDT in the ores proves that S and O elements were involved as SO42-. High δ34SV-CDT was caused by sulfur isotope fractional distillation in the hydrothermal fliud and sulfate reducing bacteria fractional in seawater, which suggests that sulfur may be derived from hydrothermal fluid and seawater. Meanwhile, the ore and wall rock have almost the same high ratio of light rare earth elements(LREE) to heavy rare earth elements(HREE), Eu and Ce anomalous, which indicates that they are the product of hydrothermal sedimentation. Additionally, biomarkers show that the organic matter is mainly sourced from the lower organisms, such as marine bacteria and algae. According to comprehensive research on metallogenic setting and Sr isotope, the material of barium mainly comes from submarine hydrothermal sediments. Comprehensively, it is believed that the ore-forming material may mainly comes from the seawater and hydrothermal sedimentation, both crustal and mantle components play important roles in providing material. Besides, lower marine organisms are involved.
Key words: material source; Dahebian barite deposit; isotope; rare earth element
