�Ű������������������Ҫ�ֲ��ڸԵ�˹�жε���ѩ������ɣ�͸������ɺ���ĸ�س������ҡ��س������ҺͶ���ĸ�س������Ҽ����������ҵ���ɡ����л���������SHRIMP �ʯU--Pb ����Ϊ68. 8 ± 1. 6 Ma; �س������Һ���ĸK--Ar ����Ϊ78. 2 ± 1. 2 Ma ��81. 5 ± 1. 4 Ma; ����ĸ�س������ҺͶ���ĸ�س������ҵĺ���ĸK--Ar �ֱ�Ϊ90. 8 ± 1. 81 Ma ��91. 2 ± 1. 8 Ma����ʯѧ�͵���ѧ�������������S �ͺ͵�Sr ��Yb �����ĺ���ĸ�س������ҺͶ���ĸ�س��������γ��������ؿ���Ǽ���ؿ���ײ��ɽ�����еĵؿǼӺ񱳾�; S �ͺ������Sr����Yb �����ļس��������γ�����ɽ�����ڽ׶ε���չ����; I �ͻ���������Ӧ��������˹�󸩳����õĽ�����γ��ڵ������컷����

The Late Cretaceous granitoids expose near by Sangba��Jianduo and Zaxue areas in the middle Gangdise tectonic belt�� The main rock types include granodiorite��granitite��moyite and binary granite�� The SHRIMP U-Pb dating on zircon from granodiorite ( tw566) is 68. 8 ± 1. 6 Ma�� The K-Ar datings on biotite from the moyite are 78. 2 ± 1. 2 Ma and 81. 5 ± 1. 4 Ma�� The K-Ar dating on biotite from the granitite and the binary granite are 90. 8 ± 1. 8 Ma and 91. 2 ± 1. 8 Ma�� Research on petrology and lithogeochemistry shows the granitite and twomica granite as the S-type granites with low Sr and low Y��resulted from the crustal thickening owing to the collision between Lasha terrane and Qiangtang terrane�� The moyite is the S-type granite with low Sr and high Y��which formed in the relaxational environment after the post-collision�� The granodiorite in the“I”type formed in the island- arc environment and resulted from the subduction of the Neotethys��