中文摘要：

对小湖闪长玢岩进行了锆石LA-ICP-MS U-Pb年代学及岩石地球化学研究。结果表明,岩石年龄为211~214 Ma,加权年平均龄值为（212.8±1）Ma,表明岩浆属于晚三叠世。依据TiO_2-Zr/P_2O_5、P_2O_5-Zr及SiO_2-K_2O图解,判断岩石为高钾钙碱性系列,A/CNK值为1.25~1.57,为过铝质。富集大离子亲石元素（如K、Rb、Ba）,相对亏损高场强元素（如Nb、Ta、P、Ti）。高Mg~#值（51.74~52.56,平均为52.17）、Nb/Ta比值（13.52~16.00）、Rb/Sr比值（0.13~0.18）、Th/Nb比值（0.34~0.37）及Ba/La比值（12.39~15.83）,显示出此岩体具有壳幔混合特点。综合前人研究成果,认为岩石形成于古亚洲洋闭合之后的造山拉张环境。

英文摘要：

LA-ICP-MS zircon U-Pb dating and geochemical data of Xiaohu diorite porphyrite were studied.The results indicate that the diorite porphyrite pluton formed in Late Triassic（ 212. 8 ± 1） Ma. Based on TiO_2-Zr / P_2O_5,P_2O_5- Zr,and K_2O- SiO_2 diagrams of rocks,the diorite porphyrite is characterized by high-K calc-alkaline and peraluminous affinities,with an A / CNK ratio ranging from 1. 25 to 1. 57,enrichment in LILE（ such as K,Rb,Ba）,relatively depleting in HFSE（ such as Nb,Ta,P,Ti）. Combined with their high Mg~# values（ 51. 74 ~ 52. 56）,Nb /Ta = 13. 52 ~ 16. 00,Rb /Sr = 0. 13 ~ 0. 18,Th /Nb = 0. 34 ~ 0. 37,Ba /La = 12. 39 ~15. 83,it can be concluded that the magmatic mixing evolution trend. Integrated the regional tectonic evolution,it is suggested the porphyrite formed in the post-orogenic extension setting,which was related to the closure of the Paleo-Asian Ocean.