������ɽ���������� LA- - ICP- - MS �������ʯ U- - Pb ��������Ϊ 245 ±1 Ma��˵�����γ���������������ʯ����ѧ�о�������������и� Si���� K��ƶ Ti��Ca��Fe��Mg ���ص�; A/KNC ��1. 1����ʾ�� S �ͻ������ص�; �̽�ָ�� (SI) Ϊ 1. 68 �� 1. 88������ָ�� (DI) Ϊ 93. 94 �� 94. 25��˵�����徭���˽ϸ̶߳ȵķ����ݻ�����; ϡ��Ԫ�������ϵ� (∑��EE =80. 10 × 10 ��6 �� 145. 06 × 10 ��6 )����ϡ�����Ը�������ϡ����Կ���Eu ���쳣����������ʯԪ�� ��b��K �ϸ���������������ɽ�������������ڸ߼ظƼ��ԡ������� S �ͻ����ҡ����ǰ����ص��о��ɹ����Ʋ⼦����ɽ�����������ǻ��������������ǰ����ײ�����γɵ�ͬ��ײ�ͻ����ҡ�

The result of LA-ICP-MS zircon U-Pb is 245 ±1 Ma��revealling that monzonitic granite in Jiguan- zi Mountain was formed in Early Triassic�� The geochemistry study of the rocks indicates that the rocks are charac- terized by high Si��K and low Ti��Ca��Fe��Mg�� The ratio of A/KNC ��1. 1 shows the characteristics of S- type gran- ite�� The SI is 1. 68 ��1. 88��DI is 93. 94 ��94. 25��indicating that the rocks experienced a relatively high degree of differentiation evolution�� The total content of ∑��EE is low (∑��EE =80. 10 ×10^-6 ��145. 06 ×10^-6 )��the L��EE and LILE (��b��K) are enriched�� the H��EE are depleted�� and it is also characterized by negative Eu anomaly�� In combination with discrimination diagram��the rocks belong to high- potassium��calc- alkaline peraluminous S- type granite�� Combining with related research��the authors infer that the monzonitic granite was syn- collisional granites caused by collided between North China and Siberia plates��