(1. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院 有色金屬成礦預(yù)測教育部重點(diǎn)實(shí)驗室，長沙 410083；
2. 江蘇省有色金屬華東地質(zhì)勘查局，南京 210007)
摘 要: 為探明大河邊重晶石礦床的物質(zhì)來源，在分析礦床地質(zhì)的基礎(chǔ)上，系統(tǒng)研究礦石礦物的同位素組成、稀土元素及有機(jī)地球化學(xué)特征。結(jié)果表明：樣品中δ18OSMOW與δ34SV-CDT呈正比關(guān)系，推測氧和硫元素以SO42-的形式參與成礦；δ34SV-CDT值較高表明硫可能來源于熱液與海水，高34S值是由熱液體系中硫同位素分餾和海洋中還原細(xì)菌分餾造成的。礦石和圍巖具有相似的高輕重稀土元素比、負(fù)鈰異常及正銪異常等特征，表明它們都為熱水沉積產(chǎn)物。生物標(biāo)志物指標(biāo)表明：有機(jī)質(zhì)主要源自于海相低等菌藻類浮游生物。綜合成礦背景和鍶同位素特征研究，推測鋇主要來源于熱水沉積作用。綜合同位素、稀土元素和有機(jī)地球化學(xué)研究認(rèn)為，大河邊重晶石礦床的成礦物質(zhì)主要來源于海水和熱水沉積作用，地殼和地幔均提供物質(zhì)來源，且海洋生物參與成礦。
關(guān)鍵字: 物質(zhì)來源；大河邊重晶石礦床；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
