(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙 410083；3. 青海西部礦業(yè)地質(zhì)勘查有限公司，西寧 810016)
摘 要: 德合龍洼銅(金)礦床為青藏高原北東端的一個(gè)巖漿熱液型礦床，成礦作用主要?jiǎng)澐譃閹r漿熱液成礦期，包含石英−黃銅礦和毒砂兩個(gè)成礦階段。在分析該礦床成礦地質(zhì)條件的基礎(chǔ)上，系統(tǒng)地研究了礦區(qū)礦石硫、鉛同位素組成，流體包裹體以及稀土元素特征，探討了成礦物質(zhì)來源。研究表明：礦區(qū)礦石硫樣品δ34(SCDT)值分布范圍較寬(−3.08×10−3~7.00×10−3)，具有巖漿硫性質(zhì)，可能來源于礦區(qū)侵入的中酸性巖體。各類型礦石鉛同位素組成穩(wěn)定，顯示正常鉛的特征，U和Th放射性成因鉛含量較低。對(duì)各類型礦石鉛同位素進(jìn)行特征參數(shù)示蹤、鉛構(gòu)造模式示蹤和∆β—∆γ圖解示蹤的結(jié)果表明：礦區(qū)礦石鉛主要為地殼與地幔混合的俯沖鉛，主要來源于俯沖造山背景下形成的巖漿侵入體。流體包裹體及稀土元素地球化學(xué)特征均表明礦區(qū)成礦物質(zhì)可能主要來源于巖漿侵入體，少許成礦物質(zhì)可能來源于周圍地層。總結(jié)礦區(qū)礦石硫、鉛同位素、流體包裹體以及稀土元素分析結(jié)果，表明成礦物質(zhì)主要來源于深部巖漿，這種巖漿的形成可能與板片俯沖造山有關(guān)，地殼與地幔組分均可提供成礦物質(zhì)來源。
關(guān)鍵字: 德合龍洼；硫同位素；鉛同位素；銅(金)礦；流體包裹體
Dehelongwa copper(gold) deposit in Qinghai Province, China
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. Qinghai Ltd. of Western Mining Geological Prospecting and Survey, Xining 810016, China）
Abstract:The Dehelongwa copper(gold) deposit, located in the north-east part of Qinghai-Tibet Plateau, is a magmatic hydrothermal deposit and the mineralization mainly belongs to magmatic hydrothermal mineralization period including two mineralization stages of quartz-chalcopyrite and arsenopyrite. Based on the research related to the deposit’s ore-forming geological conditions, the compositions of S, Pb isotopes as well as the characteristics about fluid inclusions and rare earth elements were systematically studied, and the origin of ore-forming materials was discussed. It is shown that the δ34(SCDT) values of ore minerals distribute widely (−3.08×10−3−7.00×10−3) and are similar to that of magmatic sulfur, which suggests that the deposit’s sulfur may be sourced from the intermediate-acid intrusive rocks. Meanwhile, the Pb isotopic composition of ore sulfides is stable and the ore lead is ordinary common lead with little U and Th radiogenic lead. According to the tracer analysis regarding the characteristic parameters, lead composition model and ∆β—∆γ diagram, the conclusion is drawn that the ore lead is typically crust-mantle mixed subduction lead and comes from intrusive magmatical rocks formed under the circumstance of subduction orogeny. Additionally, the geochemical characteristics about fluid inclusions and rare earth elements both suggest that mass ore-forming materials may originate from intrusive magmatical rocks while few may be sourced from around strata. Comprehensively, it is believed that ore-forming materials may mainly come from the deep magma formed by subduction orogeny, crust and mantle components both play an important role in providing them.
Key words: Dehelongwa; sulfur isotope; lead isotope; copper(gold) deposit; fluid inclusion
