花崗巖地質(zhì)地球化學(xué)特征及成因
(1. 中南大學(xué) 有色金屬成礦預(yù)測教育部重點實驗室，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)
摘 要: 納勐銅多金屬礦區(qū)主要的花崗巖類為黑云母二長花崗巖和鉀長花崗巖。巖體w(SiO2)為73.45%~77.46%；K2O/Na2O=0.73~1.40，屬于準(zhǔn)過鋁質(zhì)至弱過鋁質(zhì)富硅鈣堿性系列；巖石稀土總量偏低，明顯富集大離子親石元素，虧損高場強元素，Rb/Sr=0.40~4.00。綜合分析表明：納勐礦區(qū)花崗巖巖石成因類型相當(dāng)于Ⅰ型花崗巖，熔融溫度較高，成巖過程與幔源巖漿的底侵作用有關(guān)，熱的幔源不僅為地殼的部分熔融提供了熱量，且與熔融的殼源巖漿發(fā)生了混合作用。
關(guān)鍵字: 花崗巖；地質(zhì)特征；地球化學(xué)
granites in NaMeung copper polymetal deposit, Laos
（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）
Abstract:The outcropped rockbody is mainly biotite monzogranite, potassium granite in the NaMeung copper polymetal deposit, Laos. The main rocks belong to metaluminous to weakly peraluminous high Si calc-alkaline series, with w(SiO2) of 73.45%−77.46%, K2O/Na2O=0.73−1.40. It is obvious that the rocks are enriched in LILE and depleted in HFSE, with relatively low ∑REE contents, Rb/Sr=0.40−4.00. The analysis results show that the rockbody is similar withⅠtype, and its partially melting is in the high temperature. The formation of the granites is related to magmatic underplating. The hot mantle magma not only provides heat for the partial melting of crust, but also causes magma mixing with the crustalderived melts.
Key words: granites; geology characteristics; geochemistry
