1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Geological Survey Institute of Liaoning Province��Shenyang 110032��China

The authors explored the age�� petrogenesis and tectonic setting of intermediate- acidic dykes in Tae- rqi regions through the study in geological fieldwork�� zircon U- - Pb age and geochemical features of them�� The zircon U - - Pb age indicates that the intermediate dykes and acidic dykes were formed in Early Cretaceous including 141. 4 ��136. 0 Ma and 136. 5 �� 126. 4 Ma��respectively�� The geochemical data show that the intermediate dykes are characterized by medium silicon��alkali- rich��quasi- aluminous (A/CNK =0. 8 ��0. 92)��belonging to high- K calc- alkaline weakly quasi- aluminous series��and most of them are obvious in having Eu negative anomaly�� The acidic dykes are characterized by high silicon��alkali- rich��weakly peraluminous (A/CNK = 1. 03 �� 1. 24)��indicating high- K calc- alkaline series and most of them have no Eu negative anomaly�� Based on a synthesis of petrography�� geochronology��elemental and isotopic geochemistry��it is suggested that the intermediate dykes and acid dykes in Taerqi may be products of two stages of magmatic event under a extensional setting��