(1. 中南大學(xué) 有色金屬成礦預(yù)測教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長沙 410083；
3. 中國科學(xué)院 地球化學(xué)研究所 礦床地球化學(xué)國家重點(diǎn)實(shí)驗(yàn)室，貴陽 550002；
4. 廣西二一五地質(zhì)隊(duì)有限公司，柳州 545006)
摘 要: 利用巖石地球化學(xué)的理論與方法，對大廠礦田的主要賦礦地層泥盆系中、上統(tǒng)開展了主量元素地球化學(xué)、稀土元素地球化學(xué)以及微量元素地球化學(xué)的分析與研究，對泥盆系地層與大廠礦田礦床與礦產(chǎn)的關(guān)系進(jìn)行了探討，闡述了泥盆系的有利成礦條件及其對礦床的關(guān)鍵控制作用。結(jié)果表明，泥盆系地層主量元素成分為SiO2、CaO、Al2O3、Fe2O3、MgO、Na2O以及K2O等，以SiO2和CaO為主體，其中，納標(biāo)組地層CaO含量最高，其余各組地層SiO2含量均表現(xiàn)為不同程度的偏高，這與大廠礦區(qū)泥盆系地層的巖性特征以及巖石組合密切相關(guān)。利用Al2O3—SiO2巖石熱水成因模式顯示，泥盆系形成過程中沉積環(huán)境多變，巖石物源具有多來源的特點(diǎn)，也從一定程度上導(dǎo)致了泥盆系地層多樣化的巖性特點(diǎn)以及復(fù)雜的巖石建造。泥盆系ΣREE含量變化于(2.9~318.77)×10-6之間，其中，納標(biāo)組地層表現(xiàn)出輕、重稀土元素虧損，羅富組地層則表現(xiàn)為輕、重稀土元素富集。泥盆系地層的微量元素組成主要包括Ba、Rb、Sr、Th、U、La、Ce、Pr、Nd等。泥盆系不同組地層獨(dú)特的巖石類型與巖性組合，是金屬成礦元素發(fā)生富集的有利因素。
關(guān)鍵字: 大廠；泥盆系；地球化學(xué)；控礦因素；成礦作用
（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. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry,
Chinese Academy of Sciences, Guiyang 550002, China;
4. Guangxi No. 215 Geological Party, Liuzhou 545006, China）
Abstract:Based on the theory and method of the petrogeochemistry, the major element, REE and trace element of the Middle and Upper Devonian in the Dachang orefield were analyzed, the relationship between the Devonian and minerals was discussed, the favorable metallogenic conditions and its critical control to the ore deposit were also elaborated. The results suggest that the major elements of the Devonian consist of SiO2, CaO, Al2O3, Fe2O3, MgO, Na2O and K2O, yet SiO2 and CaO are dominant. The calcium oxide content of Nabiao formation is the maximum, but the SiO2 content of the other formations seems to be too high in different degrees, which closely relates to the lithological characteristics and rock assemblage of Devonian in Dachang orefield. According to the hydrothermal mode of Al2O3-SiO2, the depositional environment of Devonian was variable with multiple sources, which led to the diverse lithology and complex rock formations. The content of ΣREE of Devonian is 2.9×10-6-318.77×10-6, among which the Nabiao formation depletes LREE and HREE elements, yet the Luofu formation relatively enriches LREE and HREE elements. The trace elements of Devonian are composed of Ba, Rb, Sr, Th, U, La, Ce, Pr and Nd. The special rock type and lithological combination of Devonian are the favorable factors for the metal enrichment.
Key words: Dachang; Devonian; geochemistry; ore-controlling factor; mineralization
