(1. 中南大学有色金属成矿预测与地质环境监测教育部重点实验室，长沙 410083；
2. 中南大学地球科学与信息物理学院，长沙 410083)
摘 要: 通过系统地分析岩石地球化学、LA-ICP-MS锆石U-Pb年代学和锆石Hf同位素组成，对岩石的成因进行研究。结果表明：八团岩体中的锆石晶形完好，内部结构清晰，震荡生长环带发育，具有较高的Th/U比值(0.42~0.61)，显示岩浆成因的特征。对八团岩体LA-ICP-MS的U-Pb定年结果为(159.2±4.6) Ma(MSWD=0.62)，表明其属于燕山期岩浆侵入活动的产物。八团岩体属于硅酸过饱和岩石，具有富钠富钾低钙的特征，铝饱和指数A/CNK值均大于1.1，同时又兼具Rb、Th强烈富集，Nb、Sr、Ti强烈亏损的特点，岩体中轻稀土富集强烈，重稀土亏损严重，稀土配分曲线均向右倾且具有明显的负Eu异常，八团岩体中εHf(t)值为-36.03~-6.09，以上特征说明八团岩体属于典型的S型花岗岩，是由地壳经不同程度熔融而成的。
关键字: 地球化学；锆石U-Pb年代学；Hf同位素；八团岩体
（1.Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitor,
Ministry of Education, Central South University, Changsha 410083, China？
2. School of Geosciences and Info Physics, Central South University, Changsha 410083, China）
Abstract:Base on the detail analysis of geochemistry, LA-ICP-MS zircon U-Pb chronology and Hf isotopic composition about the intrusion, the genesis of granite was discussed. The results show that zircons from the intrusions display complete crystal form, clear internal structure and oscillatory zoning and high Th/U ratios (0.42-0.61), implying their magmatic origin. LA-ICP-MS zircon U-Pb dating results of the Batuan intrusion indicate that the product is Yanshanian magmatic activity with the intercept ages of (159.2±4.6) Ma(MSWD=0.62). Batuan intrusion is a supersaturated silicate rocks with the characteristics of rich sodium and potassium and low calcium. A/CNK aluminium saturation index values are greater than 1.1. At the same time, the intrusion has the characteristics of strong enrichment of Rb and Th, and strong depletion of Nb, Sr, Ti. The rock mass strongly enriches the light rare earth and strongly depletes in the heavy rare earth, rare earth distribution curve inclines to the right and has obvious negative Eu anomaly. The εHf(t) of Batuan intrusion is -36.03~-6.09. Taken together, Batuan intrusion is S-type one formed by the earth crust melt.
Key words: geochronology; zircon U-Pb dating; Hf isotope; Batuan intrusion
