ͨ�� LA--ICP--MS �ʯ U--Pb ��������ɹŰ������������������о�������������ҽ��ʯ�ļ�Ȩƽ������Ϊ 263 ±1 Ma��������ᾧ����Ϊ�ж���������ʯ����ѧ����������������и� Si ( SiO2= 69. 94% �� 72. 56%) ���� ALK ( Na2O + K2O = 8. 04% �� 9. 23%) ��ƶ Fe ( FeOT= 1. 50% �� 1. 82%) ��Mg ( MgO =0. 65% �� 0. 86%) ��Ti ( TiO2= 0. 32% �� 0. 35%) ���ص�; A/CNK ֵΪ 0. 87 �� 0. 93��Ϊ׼����; A/NKC ��1. 1����ʾ�� I �ͻ������������̽�ָ�� ( SI) Ϊ 6. 06 �� 7. 36������ָ�� ( DI) Ϊ 88. 82 ��91. 82��˵�����徭���˽�ǿ�ķ����ݻ����á�ϡ��Ԫ�������ϵ� ( Σ��EE = 91. 76 × 10 ��6��143. 16 ×10 ��6) ����ϡ�����Ը�������ϡ����Կ���L��EE/H��EE ֵƽ��Ϊ 9. 14��( La/Yb)N ƽ��ֵΪ 8. 36��δEu ƽ��ֵΪ 0. 58��Ϊ Eu �����͡���������ʯԪ�� ( LILE) ��b��K �ϸ�����ǿ�ҿ���߳�ǿԪ�� ( HFSE) Nb��Ti��Ta����ˣ��ж�����������Ϊ�߼ظƼ��� I �ͻ����ҡ���ϲ������͵���ѧ�������ж�������Ϊ�����ڻ��������������ǰ����ײ�����γɵ�ͬ��ײ�ͻ����ҡ�

LA--ICP--MS zircon U--Pb dating indicated that the ages of zircons from Kelidai pluton are (263 ± 1) Ma��related to Middle Permian�� The rocks are characterized by high Si (SiO2=69. 94% ��72. 56%)��high al- kali (Na2O + K2O = 8. 04% �� 9. 23%)��low iron��magnesium and titanium (FeOT= 1. 50% �� 1. 82%��MgO = 0. 65% ��0. 86%��TiO2=0. 32% ��0. 35%)�� A/CNK value was 0. 87 ��0. 93��A/NKC ��1. 1��belonging to quasi �� aluminous I-type granites�� The rocks experienced a highly fractionated and evolving stage reflected from DI (88. 82 �� 91. 82) and SI (6. 06 �� 7. 36)�� The rocks have low abundance of ��EE (Σ��EE = 91. 76 × 10��6�� 143. 16 ×10��6)��with variable differentiation between L��EE and H��EE (L��EE/H��EE average as 9. 14 and (La/ Yb)Naverage as 8. 36)��revealling L��EE enrichment and H��EE depletionand with negative Eu anomalies (aver- age δEu = 0. 58)��and enrichment in LILE (��b��K) but depleted in HFSE (Nb��Ti��Ta)�� In combination with the discrimination diagram��the Kelidai pluton belonged to high-potassium calc-alkaline I-type granites�� Con- sidered the chronology results and geochemical characteristics��the rocks were syn-collisional granites formed in the collision between North China and Siberia plates in Late Hercynian��