(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；3. 湖南省有色地質(zhì)勘查局一總隊，郴州 423000；
4. 湖南省有色地質(zhì)勘查局，長沙 410007)
摘 要: 新生礦區(qū)花崗巖體巖性為黑云母花崗巖和黑云母二長花崗巖。花崗巖總體上具有富鉀、高硅的特征，為鈣堿性到弱過鋁質(zhì)花崗巖的過渡(A/CNK為0.93~1.13)。花崗巖具有強烈的Eu負(fù)異常(δEu為0.15~0.35)，稀土元素配分曲線呈不對稱的“海鷗型”，與典型過鋁質(zhì)A型花崗巖的特征一致。花崗巖的10 000Ga/Al為3.62(3.47~4.00)，與世界A型花崗巖平均值3.75相接近。鋯石U-Pb年齡為(147.5±3.5) Ma(MSWD=2.6)，顯示巖體形成于燕山早期第二階段。鋯石的εHf(t)為-5.79~-4.15，暗示巖漿來源于均一源區(qū)，鋯石的Hf同位素兩階段模式年齡(TDM2)為1.208~1.290 Ga，平均為1.227 Ga，說明巖漿源區(qū)有中元古代的古老地殼物質(zhì)的加入。花崗巖構(gòu)造環(huán)境判別圖解顯示為造山后(A2)的板內(nèi)花崗巖。成礦花崗巖是在燕山早期晚階段板內(nèi)拉張背景下侵入地殼，并帶來成礦物質(zhì)形成矽卡型銅多金屬礦床。
關(guān)鍵字: 銅多金屬礦床；A型花崗巖；鋯石U-Pb定年；Hf同位素
（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. First General Geological Team of Hunan Nonferrous Metal Geo-exploration Bureau, Chenzhou 423000, China;
4. Hunan Nonferrous Metal Geo-exploration Bureau, Changsha 410007, China）
Abstract:The Xinsheng granite bodies are distinguished as biotite granite and biotite monzogranite in mining area, the granites can be classified to be calc-alkaline granite and weakly peraluminous granite with K-rich, Si-high (the values of A/CNK are 0.93-1.13). The granites have obvious Eu negative anomaly, the REE distribution patterns be long to the type of “gull”, which are the same as that of typical A-type granite. The average value of 10 000Ga/Al of granites is 3.62 (3.47-4.00), which is close to 3.75, the average value of A-type granite worldwide. The zircon U-Pb age of granite bodies is (147.5±3.5) Ma (MSWD=2.6), which shows that they formed in the second stage of early Yanshan movement. The values of εHf(t) are -5.79- -4.15, indicating that the magma mainly derived from a uniform resource. The model ages of two-stage range of zircon Hf isotope (TDM2) are 1.208-1.290 Ga (average value is 1.227 Ga). This feature indicates that the granite bodies originated from melting of early crustal materials formed in mesoproterozoic. The discrimination diagrams for tectonic background of granites prove that the granites formed in intra-plate extension environment, and the granites are A2-type, so, the granite body intrusived to lower crust in extension environment, and brought enough mineralizing material to form skarn type copper polymetallic deposit.
Key words: copper polymetallic deposit; A-type granite; zircon U-Pb dating; Hf isotope
