中文摘要：

湖北省蕲春县烈马咀花岗岩主要为黑云母二长花岗岩，由黑云母、钾长石、斜长石和石英等矿物组成，属于梅川杂岩体主岩体乱泥滩单元的组成部分。LA．ICP．MS锆石u．Pb定年结果显示，其U-Pb谐和年龄为123±0．85Ma（N=15，MSWD=0．21），206-pb／238-U表面年龄加权平均值为123±1Ma（N=15，MSWD=0．21），略晚于乱泥滩主岩体侵位年龄（131Ma）和大别山地区晚中生代岩浆活动峰期年龄（130Ma）。烈马咀花岗岩主．微量元素分析显示，主要元素以高Si02（74．76％～77．64％）、富碱（K20＋NazO7．18％～7．96％）和过铝质（A120312．73％～14．06％）为特征；微量元素以富集大离子亲石元素（如Rb和Pb等）和亏损高场强元素（如Nb、Zr、P和Ti等）为特征；稀土元素具有轻稀土富集和Eu负异常（δEu=0．4l～0．65）特征。烈马咀花岗岩成岩年龄和岩石地球化学特征显示其成因与大别山造山带内晚中生代花岗岩类似，均来自古老下地壳物质的部分熔融，形成于晚中生代整个中国东部岩石圈伸展减薄的构造背景下。

英文摘要：

Liemazui granite located in Qichun County, Hubei Province is mainly biotite monzonitic granite and is composed of biotite, potassium feldspar, plagilclase and quartz, which is a part of the Luannitan unit of the Meichuan granitoid complex. LA-ICP-MS zircon U-Pb dating indicates that the granite has a U-Pb concordant age of 123±0.85 Ma （N=15, MSWD-0.21） and mean 206pb/238U weighted age of 123±1 Ma （N=15, MSWD=0.21）. This age is a little later than the emplacement age （131 Ma） of Luannitan granite and the age （130 Ma） of large-scale Late Mesozoic magma in the Dabie Mountain. Moreover, major elements, trace elements and rare early elements analysis of Liemazui granite shows that it has high concentrations of SiO2 （74.76%-77.64%）, K20＋Na20 （7.18%-7.96%） and AlzO3 （12.73%-14.06%）. In addition, it is riched in LILE （e.g. Rb and Pb） and LREE, but with depleted HSFE （e.g. Nb, Zr, P and Ti）. Besides, it displays negative anomalies of Eu （δEu=0.41-0.65）. Therefore, the age and geochemical characteristics of Liemazui granite suggest that the genesis of it is similar to Late Mesozoic granite in the Dabie. Mountain orogenic belt and diagenesis materials were both sourced from partial melting of ancient lower ernst and these granite were generated under a setting that Late Mesozoic lithosphere extended and became thinner in the eastern China.